unigraphics nx sketching fundamentals mt10028 (student guide)

Sketcher Fundamentals

Student GuideFebruary 2006MT10028 — NX 4

Publication Numbermt10028_g NX 4

Manual History

ManualRevision

UnigraphicsVersion

PublicationDate

Version 16.0 May 2000Version 17.0 December 2000Version 18 November 2001Unigraphics NX October 2002Unigraphics NX 2 December 2003NX 3 January 2005NX 4 February 2006

This edition obsoletes all previous editions.

Proprietary & Restricted Rights Notice

This software and related documentation are proprietary to UGS Corp.

© 2006 UGS Corp. All Rights Reserved.

All trademarks belong to their respective holders.

©2006 UGS Corp.All Rights Reserved.Produced in the United States of America.

2 Sketcher Fundamentals – Student Guide mt10028_g NX 4

Contents

Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

Intended Audience . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7Course Objectives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7Prerequisites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8How to Use This Course . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8Class Standards . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9About Part File Naming . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9Seed Part . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10Definition of Terms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11Classroom System Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

Sketching . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1

Sketching Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2Sketches and the Part Navigator . . . . . . . . . . . . . . . . . . . . . . . . . 1-6Sketch Visibility . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-7

Creating a New Sketch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-8The Active Sketch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-12Sketch Creation Steps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-13Activity — Sketch Creation . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-14

Sketch Curves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-21Activity — Using the Sketch Profile Tool . . . . . . . . . . . . . . . . . . 1-28Creating Fillets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-33Trimming and Extending Curves . . . . . . . . . . . . . . . . . . . . . . . . 1-34Activity — Creating Fillets . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-37Activity — Using Quick Trim and Quick Extend . . . . . . . . . . . . 1-42

Sketch Points . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-46Dimensional Constraints . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-48

Activity — Adding Dimensional Constraints . . . . . . . . . . . . . . . 1-54Editing Dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-57Activity — Editing Sketch Dimensions . . . . . . . . . . . . . . . . . . . . 1-59

Geometric Constraints . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-63Show/Remove Constraints . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-66Constraint Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-69Activity — Adding Constraints . . . . . . . . . . . . . . . . . . . . . . . . . 1-71Activity — Constraining a Profile . . . . . . . . . . . . . . . . . . . . . . . 1-76Activity — Sketching and Constraining a Gasket . . . . . . . . . . . . 1-85Convert To/From Reference . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-92Activity — Constraint Conditions . . . . . . . . . . . . . . . . . . . . . . . 1-93

©UGS Corp., All Rights Reserved Sketcher Fundamentals – Student Guide 3

Contents

Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-99

Constraining Sketches . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1

Drag . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2Create Inferred Constraints . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-5Activity - Dragging Sketch Objects . . . . . . . . . . . . . . . . . . . . . . . . . . 2-6Activity - Adding Constraints . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-15Automatic Constraint Creation . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-22Sketch Operations — Project . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-23Activity - Projecting Objects into a Sketch . . . . . . . . . . . . . . . . . . . . 2-25Activity - Auto Creating Constraints . . . . . . . . . . . . . . . . . . . . . . . . 2-32Add Existing Curves to a Sketch . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-36Activity - Adding and Constraining Curves . . . . . . . . . . . . . . . . . . . 2-37Activity - Design Change . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-40Activity - Another Design Change . . . . . . . . . . . . . . . . . . . . . . . . . . 2-41Activity - Constraining the Perimeter of a Sketch . . . . . . . . . . . . . . 2-44Activity - Controlling Heat Transfer in a Cooling Pipe . . . . . . . . . . . 2-49Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-58

Constraint Management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1

Alternate Solution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-2Activity - Alternate Solution . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-4

Placing Sketches Where They Are Needed . . . . . . . . . . . . . . . . . . . . 3-11Activity - Creating and Positioning a Sketch . . . . . . . . . . . . . . . 3-12Activity - Positioning a Sketch . . . . . . . . . . . . . . . . . . . . . . . . . . 3-20Activity - Using Positioning Dimensions . . . . . . . . . . . . . . . . . . 3-28

Reattach . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-38Reordering Sketches . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-40Activity - Reattaching a Sketch . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-41Activity - Moving Sketches . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-45Mirroring in a Sketch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-62

Activity - Mirroring Sketch Objects . . . . . . . . . . . . . . . . . . . . . . 3-63Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-66

Sketch on Path Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1

Sketch on Path . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-3

Additional Sketching Techniques . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-1

Edit Defining String . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-2Deleting or Suppressing Sketches . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-4Activity - Edit Defining String . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-5Activity - Suppressing and Deleting Sketches . . . . . . . . . . . . . . . . . 5-10Animate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-14Activity - Animating Sketch Dimensions . . . . . . . . . . . . . . . . . . . . . 5-15

4 Sketcher Fundamentals – Student Guide ©UGS Corp., All Rights Reserved mt10028_g NX 4

Contents

Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-19

Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Index-1


Overview

Intended AudienceThis course is suited for designers, engineers, manufacturing engineers,application programmers, NC programmers, CAD/CAM managers, andsystem managers who have a need to create sketches for solid models or otherfunctions. Sketches that capture design intent will be the main focus.

Course ObjectivesAfter successfully completing this course, the student should be able to:

• Understand when and why to use sketches.

• Create sketches.

• Constrain sketches.

• Add objects to a sketch

• Incorporate Design Intent in sketches.

• Utilize additional sketch techniques.


Prerequisites

PrerequisitesPractical Applications of Unigraphics course

Basic understanding of parametric modeling.

Working knowledge of the following:

• Unigraphics Interface

• Part file saving conventions

How to Use This CourseThe format of the activities is consistent throughout this course. Stepsare labeled and specify what will be accomplished at any given point inthe activity. Below each major step are bulleted steps which describe theindividual actions that must be taken. As your knowledge of Unigraphicsincreases, the action boxes will seem redundant as the step text becomes allthat is needed to accomplish a given task.


Overview

Class StandardsThe following standards will be used in this course. Standardization allowsusers to work with and predict the organization of parts created by others.All work should be performed in accordance with these standards.

About Part File NamingIn order to facilitate the identification of design models without requiring theuser to open a part file, the user community must establish standard namesfor the various files associated with the part definition. The following is asample usage of a filenaming standard:

TIP

Currently up to 128 characters are valid for file names. A four characterextension (.prt) is automatically added to define the file type. This means themaximum number of user defined characters for the file name is actually 124.


Seed Part

Seed PartSeed parts are an effective tool for establishing customer defaults or anysettings that are part-dependent (saved with the part file). This may includenon-geometric data such as:

• Preferences

• Commonly used expressions

• Layer categories

• User-defined views and layouts

• Part attributes

TIP

Once a seed part is established, it should be write-protected to avoidaccidental modification.

Several seed part files are available for use in this course, one for inch partsand one for metric parts. These files incorporate the standards describedabove, and include the TFR-TRI view as the default view.


Overview

Definition of TermsExplicit Modeling

Explicit modeling is modeling that is not parametric. Objects are createdrelative to model space, not each other. Changes to one or more objects do notnecessarily affect other objects or the finished model. Examples of explicitmodeling include creating a line between two existing points, or creating anarc through three existing points. If one of the existing points were moved,the line/arc would not change.

Parametric Modeling

A parametric model is one in which the values (parameters) used forthe definition of the model are stored with the model for future editing.Parameters may reference each other to establish relationships between thevarious features of the model. Examples include the diameter and depth of ahole, or the length, width, and height of a rectangular pad. The designer’sintent may be that the hole is always as deep as the pad is high. Linkingthese parameters together may achieve the desired results. This is not easilyaccomplished with an explicit model.

Constraint-based Modeling

A constraint-based model is one in which the geometry of the model is driven,or solved, from a set of design rules applied to the geometry defining the modelas constraints. These constraints might be dimensional constraints (suchas sketch dimensions or positioning dimensions) or geometric constraints(such as parallelism or tangency). Examples include a line tangent to an arc,where the designer intends for that tangent condition to be maintained eventhough the angle of the line may change, or a perpendicular condition beingmaintained as angles are modified.

Hybrid Modeling

Hybrid modeling refers to the selectively combined use of the three typesof modeling described above. Hybrid modelers allow designers to useparametric modeling where needed, without requiring that the entire modelbe constrained before proceeding. Because of this, designers have moreflexibility in modeling techniques. The Unigraphics NX hybrid modelersupports traditional explicit geometric modeling along with constraint-basedsketching and parametric feature modeling. All tools are integrated so theycan be used in combination.


Classroom System Information

Classroom System InformationYour instructor will provide you with the following items for workingin the classroom:

Student Login:

User name:

Password:

Work Directory:

Parts Directory:

Instructor:

Date:


1Lesson

1 Sketching

Purpose

This lesson introduces the method of creating a sketch and free handsketching of curves.

Objectives

Upon completion of this lesson, you will be able to:

• Create a sketch.

• Create sketch curves.

• Apply dimensional constraints to sketches.

• Apply geometric constraints to sketches.

• Identify constraints.

• Convert a sketch curve to reference.

©UGS Corp., All Rights Reserved Sketcher Fundamentals – Student Guide 1-1

1

Sketching

Sketching Overview

What is a sketch?

A sketch is a collection of two-dimensional geometry within a part. Eachsketch is a named collection of 2D curves and points residing on a plane thatyou specify. You can use sketches to address a wide variety of design needs.For example, you might create.

• Detailed part features by sweeping, extruding, or revolving a sketch into asolid or a sheet body.

• Large-scale 2D concept layouts.

• Construction geometry, such as a path of motion, or a clearance arc, thatis not meant to define a part feature.

This lesson will focus on the use of sketches to define detailed partfeatures.

Sketcher tools let you fully capture your design intent through geometric anddimensional relationships that we refer to collectively as constraints. Useconstraints to create parameter-driven designs that you can update easilyand predictably. Sketcher evaluates constraints as you work to ensure thatthey are complete and do not conflict.

Sketcher offers you the flexibility to create as many, or as few, constraints asyour design requires. Geometric relations may be established between thecurves within a profile as well as with curves in other profiles and modelgeometry such as edges or datums.

1-2 Sketcher Fundamentals – Student Guide ©UGS Corp., All Rights Reserved mt10028_g NX 4

1

Sketching

Why sketch?

Sketches provide a high level of control over features and automate thepropagation of changes. You can quickly apply constraints to capture awell-known design intent.

Once a sketch is placed on a face or datum plane, it will automatically movewhen the position of the placement face/datum is changed. Since sketches donot require constraints, this approach is the quickest way to build featuresand still have a sufficient level of associativity.

The inherent ability to solve a sketch in real time means that, as rules areapplied, the sketch objects change and move to reflect the effect that theassigned rule has on the geometry. This gives you the ability to quicklychange profiles of features created using sketches.

Using Sketches for Detail Part Features

When there is a commonly used shape that varies in size, a sketch can easilyaccommodate the iterations of the design by editing a single constraint.


1

Sketching

Sketches should be used as base features of a model if the shape lends itselfto extruded or revolved geometry.

Sketches may be used in a number of different ways. Consider them for guidepaths for swept features, or as section curves for free form features.


1

Sketching

An important aspect of modeling that will help you decide how to use asketch is defining the design intent of the model. The design intent consistsof two items:

• Design Considerations — The geometric requirements on the actualpart, including engineering and design rules that determine the detailconfiguration of the part.

• Potential Areas for Change — Known design changes or iterations, andtheir effects on the part configuration.

As a general rule, the more design considerations and potential areas forchange, the more likely there are benefits from sketching.


1

Sketching

Sketches and the Part Navigator

Sketches can be created by choosing the Sketch Section icon in certain featurecreation dialogs such as Extrude and Revolve, choosing the Sketch icondirectly in the Form Feature toolbar, or by choosing Insert→Sketch.

If you create a sketch from within a feature creation dialog, the sketch of thesection remains internal to the feature. It does not display in the graphicswindow or in the Part Navigator. You can edit the sketch by accessingthe associated feature. If the same sketch is required to create additionalfeatures, you can choose the Make Sketch External option from the MB3popup menu in the Part Navigator and it will appear in the graphics window.

If a sketch is not created from within a feature creation dialog, it will appearas a separate feature in the Part Navigator.


1

Sketching

Sketch Visibility

Organizing the data in a part is an important aspect of modeling. Thesketcher helps in this endeavor by automating the visibility of sketches areactivated and deactivated.

• If a standalone sketch is created by choosing the Sketch icon in the FormFeature toolbar (or Insert→Sketch), the current work layer is assigned tothe sketch as it is created. When you subsequently activate the sketch,the work layer is set to the layer assigned to the sketch so that you do notaccidently construct objects in the active sketch across multiple layers.

• If the sketch is created internal to a feature, it automatically becomesvisible when you edit the feature and choose the Sketch Section icon inthe feature dialog.


1

Sketching

Creating a New Sketch

Defining a Sketch Plane

When creating a sketch, you first need to define the plane on which to placethe sketch curves. But, you must consider the state of the model. Sincethe goal is to develop a parametric model, all of the features need to beassociative. Is the sketch going to define the base feature? Is the sketch goingto be attached to an existing reference feature or face of an existing body?

An icon option bar shown below appears in the upper left corner of thegraphics window and contains options to define the sketch plane.

1 – Sketch in Place 4 – YC–ZC Plane 7 – Datum CSYS2 – Sketch Plane 5 – XC–ZC Plane 8 – OK3 – XC–YC Plane 6 – Datum Plane 9 – Cancel

Defining the Sketch as the Base Feature

If the sketch is going to define the base feature and there is no existinggeometry or reference features in the part, you may define the plane bychoosing one of the following options:

• XC-YC Plane• YC-ZC Plane• ZC-XC Plane• Datum CSYS

Initially, the XC-YC plane will be highlighted in the graphics window. Youcan accept this plane or choose one of the other options.

To accept the plane, choose OK (MB2).

After the plane is accepted, the view in the graphics window isautomatically oriented so that it is parallel to the sketch plane. If youdo not want the view to be oriented in this manner, you can turn offthe Change View Orientation setting in Preferences→Sketch.


1

Sketching

Associate Sketch to Existing Face or Reference Feature

You can also define the sketch plane on an existing planar face, DatumPlane, or Datum CSYS. A relative Datum Plane or Datum CSYS may alsobe created on the fly.

To create the sketch on an existing face, Datum Plane, or Datum CSYS plane.

• Select the face, Datum Plane, or Datum CSYS plane.

• Define the horizontal or vertical reference.

• Choose OK.

To create a relative Datum Plane on the fly:

• Choose Datum Plane from the icon option bar in the upper leftcorner of the graphics window.

• Select the required objects to define the Datum Plane.

• Choose OK in the Datum Plane dialog.

• Define the horizontal or vertical reference.

• Choose OK.

A similar procedure can be used to create a relative Datum CSYSon the fly.

If there is an existing Datum CSYS in the part and it is coincident with theWCS. The X-Y plane of the Datum CSYS will initially highlight as the defaultsketch plane. If you choose the XC-YC, YC-ZC, or ZC-XC option, you will beasked whether to use the corresponding Datum CSYS plane instead.


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Sketching

Defining the Reference Direction

The reference direction is used to specify the horizontal direction on thesketch plane. When there is no linear object pointing in the desired horizontaldirection, a vertical reference may be defined. Because vertical is 90 degrees(counterclockwise) from horizontal by definition, the horizontal directionis interpreted from it.

In the example below, the shaded face (1) is specified as the placementface. An edge (2) is defined as the vertical reference. The resultant sketchorientation is shown to the right.

The direction of an axis may be changed as follows:

• To flip the direction of a sketch axis, double-click on it.

• To specify a new direction, select the axis to redirect and then select astraight edge. The straight edge is projected to the sketch plane to definethe new direction.

If a datum plane is selected to define the sketch plane, a Z axis willalso be displayed. The normal of the sketch plane may be changed bydouble-clicking on the Z sketch axis.


1

Sketching

Naming a Sketch

Since a unique name is required for each sketch, a default name willinitially be assigned with a numeric suffix. The format of the default nameis "SKETCH_###" where ### is replaced by the next sequential three digitnumber beginning with 000 (SKETCH_000, SKETCH_001, etc.). A sketchname may be defined during or after the sketch has been created by clickingon the default sketch name, typing in the new name and pressing Enter.

The sketch can also be renamed by choosing Sketch→Sketch Properties.

Sketches should be given descriptive names rather than accepting thedefault. This allows downstream users to understand the functionof the sketch at a glance.


1

Sketching

The Active Sketch

In any given part there may be numerous sketches of different featuresat different orientations. When using the sketcher, only one sketch maybe worked on at a time. This sketch is called the active sketch. Curvescreated while a sketch is active become associated with the active sketch.When returning to a sketch to add to or modify a profile, the sketch must beactivated. There are a few ways to activate a sketch:

• Double-clicking on a sketch curve.

• In the Part Navigator double-click on the sketch feature node.

• Choose the Sketch icon and select the desired sketch from the SketchName pull-down.

There are also a few ways to deactivate an active sketch:

• Choose the Finish Sketch icon.

• Choose Sketch→Finish Sketch.

• Activate a different sketch.

• Choose Sketch→New and create a new sketch.


1

Sketching

Sketch Creation Steps

Sketch for a Base Feature

• Set the work layer for the sketch.

• Choose the Sketch icon.

• Define the sketch plane on a WCS plane (XC-YC, YC-ZC, or ZC-XC) orcreate a Datum CSYS at absolute coordinates.

• Name the sketch.

• Choose OK.

Sketch on an Existing Face or Reference Feature

• Set the work layer for the sketch.

• Choose the Sketch icon.

• Select the face, Datum Plane, or Datum CSYS plane. (You could alsocreate a relative Datum Plane or Datum CSYS on the fly.)

• Define the horizontal or vertical reference

• Name the sketch.

• Choose OK.


1

Sketching

Activity — Sketch Creation

In this activity, you will create a sketch on an existing face and anothersketch on a datum plane that is created on the fly.

Step 1: Open the seedpart_in part.

Step 2: Start the Modeling application.

Step 3: Create a sketch for a base feature.

Make layer 21 the work layer.

Choose the Sketch icon. (Insert→Sketch)

Choose the YC-ZC Plane.

Click on the sketch name, key in base and press Enter.

Choose OK. (MB2)

The sketch is created. In addition, a fixed datum plane is createdon the specified sketch plane and two fixed datum axes are createdalong its major axes.

The specified sketch plane defines a Feature Coordinate System(FCS) for the sketch such that the X axis is parallel to thehorizontal direction and the Y axis is vertical. The WCS isautomatically manipulated to the FCS orientation to facilitatethe creation of sketch geometry.

Step 4: Exit the Sketcher.

Choose the Finish Sketch icon. (Sketch→Finish Sketch)

Step 5: Close the part and do not save.

Step 6: Open the sketch_creation_1 part.


Step 8: Create a sketch on an existing face.

Make layer 21 the work layer.


1

Sketching


The Sketch Plane icon is already selected.

Select the face (1) shown below.

The 2D sketch plane indicator appears and the X-Axis is active(highlighted).

Select the horizontal reference (2) at the location shown below.

Click on the sketch name, key in skt1 and press Enter.

Choose OK. (MB2)

Step 9: Create a curve on the sketch plane.

Choose the Circle icon. (Insert→Circle)


1

Sketching

Create a circle by selecting at location (1) and then location (2).

Choose the Finish Sketch icon. (Task→Finish Sketch)

Step 10: Change the orientation of the face that defines the sketch plane.

Choose Tools→Expression.

Select the expression Change_Me and change the formula to3.5.

Choose OK.

Rotate the part and notice how the circle remains associativeto the face.

Step 11: Create a sketch on a datum plane.

Orient the view to Trimetric. (Home key)

Make layer 22 the work layer, layer 21 invisible, and layer 1selectable.


Choose Datum Plane.


1

Sketching

Select the two shaded faces shown below.

Choose OK in the Datum Plane dialog.

A center datum plane is created.

The 2D sketch plane indicator appears and the X-Axis is active(highlighted).


1

Sketching

Select the edge for the horizontal reference at the locationindicated below.

Click on the sketch name, key in skt2 and press Enter.

Choose OK. (MB2)

XC

YC

ZC

Choose the Finish Sketch icon.

Step 12: Activate an existing sketch by selecting geometry.

Make layer 21 selectable.


1

Sketching

Double-click on the sketch curve (1) shown below.

Fit the view. (MB3→Fit)

Sketch SKT1 is activated and oriented in the graphics window.


Step 13: Activate an existing sketch by name.

Choose the Sketch icon.


1

Sketching

Choose SKT2 from the sketch name option menu.

Sketch SKT2 is activated and oriented in the graphics window.

XC

YC

ZC


Step 14: Close the part.


1

Sketching

Sketch CurvesSketch curves are created via the Sketch Curve toolbar. As curves arecreated geometric constraints are assigned to the curves relative to the InferConstraints Settings.

1 – Profile2 – Line3 – Arc4 – Circle

Infer Constraint Settings

The Infer Constraints Settings dialog determines which constraints areautomatically created during curve creation. It is accessed by choosingthe Infer Constraint Settings icon from the Constraints toolbar orTools→Constraints→Infer Constraint Settings.

As you create the curves a symbol will appear near the curve being created torepresent the constraint that will be applied, if any.


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Locking a Constraint

When a constraint symbol appears during curve creation you may lock in thatconstraint by pressing MB2. For example, if you are creating a line and theparallel symbol appears, press MB2. As you move the cursor, the new linethat is rubber banding is doing so parallel to the reference curve.

Snap Angle

The snap angle is a preference setting in the Sketch Preferences dialog that isapplied when curves are being created. It is used to "snap" a line to horizontalor vertical. The default snap angle is set to 3° and is user definable between0° and 20°. This angular tolerance is defined on either side of horizontal orvertical from the first specified location, effectively creating a 6° tolerancezone by default.

When creating lines outside of the sketcher, snap angle only applieswhen using inferred cursor location.

Snap Point Toolbar

The Snap Point toolbar can be displayed when creating most of the curve typesin the sketcher so that you have more control over the selection of locations.

When the Snap Point toolbar is active, regardless of the point types turnedon, cursor location is always available.


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Alignment Lines While Creating Curves

In the process of creating a curve, if you are horizontally or vertically oppositea control point, the system will display an alignment line. The example belowdepicts an existing curve (1) with a new curve (2) being created as well as thealignment curves (3).

Profile Tool

The Profile tool allows creation of a string of lines and arcs without having tospecify a start for each curve after the first curve is created. The Profile toolis turned on by default when you first create a sketch and can be accessed bychoosing the Profile icon on the Sketch Curve toolbar.

The icon options in the upper left corner of the graphics window allow you toswitch between creating lines (1) or arcs (2) and allow you to switch betweenCoordinate Mode (3) or Parameter Mode (4). Line creation and CoordinateMode are the defaults.

Once you have created the first curve (line or arc), the default will revert backto Line. You can switch to arc creation by using press-drag-release with MB1.


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The "circle-X" symbol (1) controls the direction in which the arc will becreated.

If the desired arc is in the wrong direction, release MB1, pass the cursor overthe end of the line, and exit in a different quadrant of the symbol.

Arc originating fromtop quadrant

Arc originating fromleft quadrant

Arc originating fromright quadrant

Arc originating frombottom quadrant

As you create curves with the profile tool, the string mode can be brokenby clicking MB2.


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Creating Lines

Line creation is accessed by choosing the Line icon on the Sketch Curvetoolbar.

Once in line creation, the icons in the upper left corner of the graphics windowprovide two options: Coordinate Mode (by cursor location or keying in an XCand YC coordinates) and Parameter Mode.

There are several ways to create a line:

• Locate the start, and then locate the end.

• Locate the start, and then enter the length and angle parameters.

• Locate the start, enter one parameter, and then locate the end.

• Key in the parameters and then locate the start.

Once you indicate a start location, the system will switch to the ParameterMode. But, you can still specify an end location without switching back toCoordinate Mode.


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Creating Arcs

Arc creation is accessed by choosing the Arc icon on the Sketch Curve toolbar.

Once in arc creation, the icons in the upper left corner of the graphics windowgive you two sets of options. The first is creation method, and the second isfor the Coordinate/Parameter Mode.

There are two different arc creation methods:

Arc by 3 Points — There are several ways to create the arc withthis method:

• Locate the start, locate the end, and then locate a point on the arc.

• Locate the start, enter a radius value and press Enter, locate the endpoint, and then move the cursor to preview and choose which of thefour possible solutions to create.

• The same as the previous, but enter the radius value after locating theend point, but before the point on arc.

Arc by Center and End Points — There are several ways to createan arc with this method:

• Locate the center, locate the start point, and locate the end point. (Thestart point location determines the radius.)

• Locate the center, locate the start point, enter a radius value and pressEnter, locate the end point.

• Locate the center, enter radius and sweep angle values and pressEnter, locate the start of the sweep, and specify the direction for thesweep.

Once you indicate a first location, the system will switch to ParameterMode. But you can still specify locations with the cursor without switchingback to Coordinate Mode.


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Creating Circles

Circle creation is accessed by choosing the Circle icon on the Sketch Curvetoolbar.

Once in circle creation, the icons in the upper left corner of the graphicswindow provide two sets of options. The first is creation method, and thesecond is for the Coordinate/Parameter Mode.

There are two different circle creation options:

Circle by Center and Diameter — There are a few ways to create acircle with this option:

• Locate the center, and then locate a point on the circumference ofthe circle.

• Locate the center, enter a Diameter, and press Enter. The circle iscreated. You are then in multiple circle creation mode - just indicateanother location for a circle center.

• Locate the center, drag the radius until you get the size you want.Press Enter. The circle is created, and you are in multiple circlecreation mode. Indicate another center.

Circle by 3 Points — There are two ways to create a circle withthis option:

• Locate three points on the circumference of the circle.

• Locate two points on the circumference of the circle, enter a radiusvalue and press Enter, then choose which of the two options you wantby cursor location.

Once you indicate a first location, the system will switch to the enterParameters mode. But you can still give a location without changingback to XY.


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Activity — Using the Sketch Profile Tool

In this activity, you will use the Profile tool to create sketch geometry.

Step 1: Open seedpart_in and save it as ***_sketch_profile_1 where ***represents your initials.


Step 3: Change the Work Layer to 21.

Step 4: Create a sketch on the XC-YC plane.


Choose OK to accept the XC-YC Plane.

Step 5: Add icons to the Sketch Constraints toolbar.

Select the Toolbar Options area of the Sketch Constraintstoolbar and choose Add or Remove Buttons→SketchConstraints.

Make sure the Infer Constraint Settings and Create InferredConstraints icons are toggled on.

You may have to move the toolbar to see the icons afterthey are added.

Step 6: Set the Infer Constraints Settings.

This is done so that only the constraints that you may want toapply will be available during curve creation.


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Choose the Infer Constraint Settings icon.(Tools→Constraints→Infer Constraint Settings)

Turn on only the following constraints.

HorizontalVerticalTangentParallelPerpendicularCoincidentDimensional Constraints

Choose OK.

Step 7: Create a Profile.

In this step you will create the sketch curves shown below usingthe Profile tool.

Choose the Profile icon (Insert→Profile) and move thecursor into the graphics window.

Select a start location with the cursor near the bottom leftcorner of the graphics window (approximately XC=-4, YC=-2)


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Move the cursor so that the rubber-banding line snaps to thehorizontal orientation and the horizontal symbol displays (1)as shown below.

Notice the horizontal symbol indicating the constraint that isgoing to be applied to the line.

Press MB2 to lock in the horizontal constraint.

Now notice that as you move the cursor around, therubber-banding line remains horizontal.

Key in 3 for the Length and press Enter.

Notice that a dimensional constraint is created automatically.This is because a Length value was explicitly entered andthe Dimensional Constraints option was turned on in theInfer Constraint Settings dialog.

Hold MB1 down and drag the cursor straight up from the endpoint of the last line and then release.

You are now in Arc creation mode.


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Key in 1 for the Radius and press Enter.

Key in 180 for the Sweep Angle and press Enter.

Click MB1 in the graphics window to apply.

Continue using the Profile tool to create the remaining curvesin the sketch as shown below. You do not have to key in exactvalues but just create the approximate shape.

Close the profile by selecting the end point of the first line.

Dimensions maybe added at a later time to constrainthe remaining curves to specific sizes.


Step 8: Save and close the part.


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Optional Challenge

Practice sketching the following profiles:


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Creating Fillets

Fillet creation is accessed by choosing the Fillet icon on the Sketch Curvetoolbar.

Once in fillet creation, icon options appear in the upper left corner of thegraphics window. The Trim Inputs option (1) determines whether or not theoriginal curves are trimmed. The Delete Third Curve option (2) determineswhether the middle curve is deleted in a three-curve fillet. The CreateAlternate Fillet option (3) will produce a complementary solution for the fillet(e.g. a 270 degree arc instead of the default 90 degree arc).

You can create fillets between lines, arcs or conics. You can also create a filletbetween two parallel lines.

There are several ways to create Fillets:

• Select two curves with a single selection (at their intersection), and thendrag the size and quadrant.

• Select two curves individually, and drag the size and quadrant.

• Select one curve, enter a radius value, and select the second curve.

• Select two curves individually, enter a radius value, and the indicate thedesired quadrant.

• Drag (with MB1) across the two curves you want to fillet. The size of thefillet is determined by where the curves are selected.


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Trimming and Extending Curves

Quick Trim

This option will allow you to trim any curve to the closest curve in the sketchand preview the results in preselection color.

You can trim multiple curves at one time, by using the "crayon" select method.Hold down MB1 and drag across the portion of curves you want to trim away.

You can select a specific curve to trim to, by using Ctrl-select to select thedesired boundary curve. More than one bounding curve can be selected usingthis method.

In the example below, both the arc on the left and the spline on the right wereCtrl-selected as boundary curves. With the cursor on the top line, (betweenthe two boundary curves), the center section is previewed as the portion tobe removed.


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When a curve is trimmed, appropriate constraints are automatically created.In the previous example, two Point on Curve constraints and one Collinearconstraint are added. If one of the boundary curves is later trimmed to theline, the Point on Curve constraint would change to Coincident.

If you trim an arc to a line that is tangent, the tangency constraint is retained.


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Quick Extend

This option will extend lines, arcs and conics to the closest curve in thesketch. The system will preview the results in the preselection color.

The curve being extended must extend to an actual intersection with theboundary curve.

You can extend multiple curves at one time, by using the "crayon" selectmethod. Hold down MB1 and drag across the ends of curves you want toextend.

You can also select specific boundary curves by using the control-selectmethod.

As with Quick Trim, when you use Quick Extend, appropriate constraints areautomatically created.


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Activity — Creating Fillets

In this activity, you will create fillets in an existing sketch.

Step 1: Open the sketch_fillet_1 part.


Step 3: Activate the sketch.

Double-click on any of the sketch curves.



Turn off the Dimensional Constraints setting.

Choose OK.

Step 5: Create a 4 mm radius fillet using lines L16 and L20 with a singleselection and trimming the lines.

Choose the Fillet icon. (Insert→Fillet)

Make sure Trim Inputs is on (highlighted background).


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Key in 4 in the Radius field on the graphics window, and pressEnter.

Select both lines at the same time, by selecting at theirintersection.

Drag the cursor around the screen and notice that you canselect which quadrant you want.

Select in the lower right quadrant to place the fillet in thedesired quadrant.

Step 6: Create a 4 mm fillet using lines L16 and L17 with a single selectionand do not trim the lines.

Turn off Trim Inputs. (background not highlighted)


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Select the two lines at their intersection.

Select in the upper right quadrant.

Step 7: Create a 4 millimeter fillet between lines L17 and L18. Select bydragging across the two lines.

The 4.0 Radius value should still be in the text field on thegraphics window.

With MB1 held down, drag across the two lines as below: (Thisis another method of selecting the curves to be filleted. Thecurves crossed with the "crayon" are the curves selected.)

Notice that the 4 millimeter radius was used.


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Step 8: Create another fillet between lines L18 and L20 by using the"crayon", but this time do NOT use a radius value.

Use Backspace to erase the 4 in the text field.

Drag (with MB1), as shown below:

It used the selection location of the curves to determine theradius.


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Step 9: Create a fillet between lines L18 and L19, and drag the size andquadrant.

Individually select the lines L18 and L19.

Drag the cursor around the screen.

Select a location to create an arc similar to the one shown below.




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Activity — Using Quick Trim and Quick Extend

In this activity, you will trim and extend existing sketch geometry.

Step 1: Open the sketch_quick_1 part.


Step 3: Trim curves with Quick Trim.

Double-click on one of the sketch curves to activate the sketch.

Choose the Quick Trim icon. (Edit→Quick Trim)

Select the line at the location of the arrow below.


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Hold MB1 down and drag the cursor across the two curves asshown below.

Ctrl-Select the curves (1) and (2) for boundaries. Select oncurves (3) and (4) to trim the center portion.

Step 4: Extending curves with Quick Extend.

Choose the Quick Extend icon. (Edit→Quick Extend)


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Place the cursor on the arc at location (1) shown below.

The status line informs you that the curve cannot be extended.This is because there is no other curve that would intersectthe arc.

Place the cursor on the arc at location (2) shown below.

This time, an intersection is found and a preview is provided.

Select the arc at location (2) to create the extension.


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Step 5: Continue to experiment with Quick Trim and Quick Extend untilthe instructor is ready to continue.

Step 6: Choose the Finish Sketch icon.



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Sketch PointsSketch objects are defined by theoretical points. A line, for instance, is definedby two points. The sketcher attempts to mathematically solve for the locationof the points by analyzing the constraints (rules) that are placed on objects.

The points that the sketch solver analyzes are referred to as sketch points.By controlling the locations of these sketch points the curve itself may becontrolled. There are various ways to control these points. The sketch pointsassociated with different types of curves are illustrated in the graphic below.

Line Arc Circle Fillet

Spline Point Ellipse

Degree-of-Freedom (DOF) Arrows

Degree of freedom arrows are displayed at a sketch point when the solver isunable to fully determine where the sketch point is located on the sketchplane based on existing constraints and dimensions. They are only displayedduring the creation of dimensions or constraints.

The DOF arrows can point in both the horizontal and vertical directions. Anarrow pointing to the right means that the sketch point is free to move left orright in the horizontal direction. An arrow pointing up means that the sketchpoint is free to move up or down in the vertical direction.

These arrows provide visual feedback while you are constraining the sketch.

Undefinedin X and YDirections

Undefined inY Direction

Undefined inX Direction

Defined inX and YDirections

(no display)


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DOF arrows are removed as rules are written that define the location of thesketch points.

• Arc - Arcs have sketch points at the center and at either end. Thesesketch points as well as the radius of the arc may be defined.

• Circle - Circles may have the center point as well as a radius or diameterdefined.

• Ellipse - An ellipse may have the location of its center defined; also, theparameters for the size and orientation of the ellipse are stored for futureediting.

• Fillet - A Fillet is a special case of arc. By definition a fillet is tangent tothe objects with which it is associated and this rule is applied as it iscreated. Fillets are also defined by the center and end points but thetangency will help determine the location of these points.

• Line - Lines may have the sketch points at either end defined.

• Point - Points may be defined relative to other objects or at specificlocations in space.

• Spline - Degree three splines may have their defining points located.Slopes of the spline at the defining points may also be defined. Splinesthat are of a degree other than three may be added to sketches; however,since their defining points are not located at their knot points, there is noway to locate their defining points using constraints.

If any of the sketch points that define a curve are unconstrained, the curve isdisplayed in the color specified by the Partially Constrained Curves settingin Preferences→Sketch→Colors. When all defining points are constrained,the curve will change to the color specified by the Fully Constrained Curvessetting in Preferences→Sketch→Colors. Theses colors only apply during thecreation of dimensions or constraints.


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Dimensional Constraints

Design Intent

The power in sketching is derived from the ability to capture design intent.

You do this by creating rules, called constraints, that dictate how sketchobjects will react to changes.

As many or as few constraints as necessary may be applied to cause thesketch profile to update in the manner desired.

NX sketches are not required to be fully constrained.

There is one case where a sketch should always be fully constrained:a sketch-on-path used for a variational sweep.

Creating Sketch Dimensions

A dimension controls the size of a sketch object, such as the length of a line orradius of an arc, or the relationship between two objects, such as a distanceor angle.

Dimensions appear in the graphics window. Unlike drafting dimensions,changing the value of the sketch dimensions changes the shape and or size ofdimensioned objects. This changes any features, such as extrude or revolvefeatures, that the sketch curves control.


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Dimensions may be applied by usingthe dimension menu on the SketchConstraints toolbar.

1 — The default Inferred Dimensions iconinfers the dimension type based on theobjects that are selected and the positionof the cursor.

2 — The other dimension icons are usefulwhen the system is unable to infer thedesired dimension type. These differentoptions are "filters" that when selectedwill only allow a specific dimension typeto be created.

Certain types of geometry may not beselectable if they do not coincide with thedimension type selected.

As dimensions are being created, the dimension, its extension lines, andarrows are displayed as soon as the geometry has been selected.

• Drag the dimension until it is the correct type, for example horizontalor parallel.

• Place the dimension by clicking MB1.

• Click and drag the dimension to the desired location.

Sometimes, a dimension type may be inferred before all of the geometry hasbeen selected. In this case, continue to select geometry until the correctdimension type is displayed, or select the icon for the dimension type youdesire and select the geometry again.


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An expression is also created for each dimension. The name (1) and value(2) of the expression appear in a text box in the graphics window after thedimension has been placed. You may key in a new name or value. Pressthe Enter key to activate the change.

Sketch Dimension Dialog

The Sketch Dimensions Dialog icon accesses the Dimensions dialog.

You can use the dialog to help create and edit dimensions. You can change thevalue of a dimension by either keying it in or using the slider bar.

There are also two option menus to change the appearance of the dimension.

The Placement option menu is for defining how the text and arrows of thedimension will be displayed. Options are for automatic placement of text andarrows (1), manual text placement with arrows inside the extension lines (2),or manual text placement with the arrows outside the extension lines (3).


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The Leader option menu is for defining whether the dimension’s leader isattached to the left (1) or right (2) of the dimension text.

Both of these option menus may be used before, during or after dimensioncreation.

Text Height

The Text Height controls the displayed height of the dimension text.Modifying this value will affect the display of all dimensions in the activesketch.

The Text Height option can also be accessed by choosingPreferences→Sketch.

The Fixed Text Height option in Sketch→Preferences controls the size ofthe dimension text when you zoom. If this option is turned on, the text willremain the same size relative to the screen as you zoom in and out.

Dimension Types

Inferred — The dimension type (except perimeter) is inferred based onthe objects selected and the cursor location.

Horizontal — Specifies a distance constraint between two points withrespect to the X-axis of the sketch coordinate system. Points, points on sketchcurves, edges, lines, and arcs are selectable.


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Vertical — Specifies a distance constraint between two points withrespect to the Y-axis of the sketch coordinate system. Points, points on sketchcurves, edges, lines, and arcs are selectable.

Parallel — Specifies a constraint for the shortest distance between twosketch points. All sketch objects are selectable using this method. The pointsselected will be inferred from the objects selected.

Perpendicular — Specifies a distance constraint measuredperpendicular to a selected line and a point. If the desired point is anendpoint of a line, this endpoint must be selected as the second object.


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Angular — Specifies an angular constraint between two linear objects.

Radius — Specifies a radial size constraint for an arc or circle.

Diameter — Specifies a diameter size constraint for an arc or circle.

Perimeter — Constrains the collective lengths of lines and arcs to adesired value. After selecting the curves and choosing MB2, an expressionis automatically generated with a “Perimeter_” prefix added to the name.(i.e. Perimeter_p7=6.456). There will be no graphical representation of thisconstraint in the graphics window.


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Activity — Adding Dimensional Constraints

In this activity, you will capture the design intent for a part by adding rulesthat will control how the part is to change. These rules allow the part to beeasily modified.

The included angle of the adjustment slot should change from 45° to75° by dimensional constraints.

Step 1: Open angle_adj_1.


Step 3: Add the required dimensions.

Double-click on one of the sketch curves to activate the sketch.

Choose Preferences→Sketch.

Verify the Text Height is set to .10 and choose OK.

Choose the Inferred Dimensions icon.(Insert→Dimensions→Inferred)

Select the lower angled line (1, not endpoint).

The system infers that you wish to create a horizontal, vertical,or parallel dimension depending on the placement of the cursorrelative to the geometry. DO NOT PLACE THE DIMENSION!


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Select the upper angled line (2, not endpoint).

Select a cursor location to place the dimension.

Select the horizontal line (1, not endpoint) across the bottom.

Select the lower angled line (2, not endpoint).


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Select a cursor location to place the dimension.

Choose MB2 to exit dimension creation mode.

Step 4: Change the viewpoint.

Choose MB3→Orient View to Model.


There are times, such as geometry creation, when looking directlyat the plane of the sketch is beneficial. At other times, it mayhelp to change the view point to see the effects of changes on thegeometry.



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Editing Dimensions

The editing of dimensions may be achieved as follows:

• To edit the value or the name, simply double-click on the dimension andedit the value or the name in the text box and press Enter.

• To edit the position, place cursor over a dimension, press and hold downMB1, and simply drag the dimension’s location.

• Additional editing that may be done with the Dimensions dialog as listedbelow:

Name — Key in a new name in the text entry field.Value — Key in a new value in the text entry field or use

the slider.Position — Click and hold MB1 on the dimension and drag

to new position.Text placement — Select a different option from the option menu.Leader side — Select a different option from the option menu.Text height — Key in a new text size in the text entry field.

The name and value of a dimension may also be edited by using theExpressions dialog. As dimensions are edited, the constraints areevaluated and the geometry is modified.

Delay Evaluation

Delay Evaluation prevents geometry changes as one or more dimensions aremodified. This is available as an icon on the Sketcher toolbar or by choosingTools→Delay Sketch Evaluation.

Evaluate Sketch

Evaluate Sketch controls sketch evaluation when Delay Evaluation is on.(Sketches are evaluated automatically when you exit from the Constraintsdialog.) This is available as an icon on the Sketcher toolbar or by choosingTools→Evaluate Sketch

Update Model

Update Model forces the model to update without leaving the sketchfunction. (The model is updated automatically when you exit from the sketchenvironment.) This is available as an icon on the Sketcher toolbar or bychoosing Tools→Update Model.


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Retain Dimensions

When a sketch is deactivated the dimensions are normally hidden.

Retain Dimensions is a toggle in the Sketch Preferences dialog to retaindimension display after the sketch is deactivated.

Retain Dimensions applies only to the active sketch, thus to suit your needsyou may have a mixture of sketches with and without retained dimensions.

Use this setting when you need to display dimensions without an activesketch, for example to reference expression names between sketches, whencreating features, or for plotting.


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Activity — Editing Sketch Dimensions

In this activity, you will edit dimensional constraints and see that they do notsufficiently control the angle bracket from the previous activity.



Step 3: Change the layer settings.

Make layer 1 Selectable.



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Step 4: Edit a dimension.

Place the cursor over a sketch curve and choose MB3→Edit.


Double-click on the 45° dimension.

In the dynamic input field, key in 75 and press Enter.


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Step 5: Edit another dimension.

Double-click on the 15° dimension.

In the dynamic input field, key in 25° and press Enter.

Notice how the geometry updates.

Basic geometric assumptions that we make when we look at thisgeometry are not specified to the system, i.e. the bottom line hasno horizontal constraint applied.

If the geometry had been created in the sketch rather than added tothe sketch some of these geometric assumptions would have beenadded to the geometry as constraints during the creation process.


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Choose Undo twice. (MB3→Undo)


Close the part.


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Geometric ConstraintsA geometric constraint establishes a geometric characteristic of a sketchobject (such as defining a line as being horizontal) or the type of relationshipbetween two or more objects (such as requiring that two lines be parallel orperpendicular, or that several arcs have the same radius).

Unlike dimensional constraints, geometric constraints have no editablenumeric values; a constant angle constraint, for instance, simply dictates thatthe line stay at the angle it is at when the constraint is applied.

To create geometric constraints, choose the Constraints icon, select theobjects, and choose the desired constraint from the icon option bar thatappears in the upper left corner of the graphics window. Only icons forconstraints that apply to the selected geometry will be displayed.

You may also choose the constraint from an MB3 pop-up menu after selectingthe geometry.

To assign multiple constraints at one time, press the Ctrl key whileselecting the objects. The icon option bar for the constraints willthen remain in the upper left corner of the graphics window afteryou choose the first constraint. You can use MB2 or the Esc key tocancel creation of constraints.


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Types of Geometric Constraints

Coincident Constrains two or more points as having thesame location.

Collinear Constrains two or more linear objects as lying onor passing through the same theoretical straightline.

Concentric Constrains two or more arcs as having the samecenter.

Constant Angle Constrains a line so as to remain in its currentorientation without input of an angular value.

Constant Length Constrains a line so as to remain at its currentlength without input of a length value.

Equal Length Constrains two or more lines as being the samelength.

Equal Radius Constrains two or more arcs as having the sameradius value.

Fixed Constrains unchangeable characteristics forgeometry, depending on the type of geometryselected. You can apply a Fixed constraint to anindividual sketch point or to an entire object.

Horizontal Constrains a line as being parallel to the FCSX-axis.

Midpoint Constrains the location of a point to beequidistant from both ends of the curve.

Select the curve anywhere other than atits end points.

Parallel Constrains two or more linear objects as beingparallel to each other.

Perpendicular Constrains two linear objects as beingperpendicular to each other.

Point on Curve Constrains the location of a point as lying on thepath or projection of a curve.

Point on String Constrains the location of a point as lying on anextracted string.


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Scale,Non–Uniform

When applied, a spline will scale in the horizontaldirection while keeping the original dimensionsin the vertical direction during modification.

Scale, Uniform A spline will scale proportionally in both thehorizontal and vertical when the horizontallength changes.

Slope of Curve Constrains a spline, selected at a defining point,and another object as being tangent to each otherat the selected point.

Tangent Constrains two objects as being tangent to eachother.

Vertical Constrains a line as being parallel to the FCSY-axis.

Displaying Constraint Symbols

Constraint symbols are displayed when a sketch is active. Symbols forCoincident, Point on Curve, Midpoint, Tangent, and Concentric are alwaysdisplayed.

The Show All Constraints option will display the symbols for all theconstraints in the active sketch.

The various constraint symbols are shown below:

Fixed Constant Angle

Collinear Concentric

Horizontal Tangent

Vertical Equal Radius

Parallel Coincident

Perpendicular Point on Curve

Equal Length Midpoint of Curve

Constant Length Point on String

Mirror Scale, Uniform

Slope of Curve Scale, Non-Uniform

If the sketch curves are relatively small (the view is zoomed out), thesymbols may not be displayed. You may need to zoom in to see them.


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Show/Remove Constraints

Show/Remove Constraints helps you manage constraints. The constraintsmay be listed by object(s) or all of the constraints of the active sketch maybe listed at once.

1 — List all constraintsor by object(s).

2 — Filter for the typeof constraint to list.

3 — Determines if thefiltered constraint typeswill be included or excluded.

4 — Category ofconstraints to list.

5 — Actions to take on thelisted constraints.

Constraint Interrogation

While the Show/Remove dialog is displayed, you can determine whatconstraints are present by passing the selection ball over a sketch object. Ifthe object has an associated constraint, the object will be pre-highlightedalong with any other objects that share the constraint. The constraint symbolwill appear next to the sketch objects. If an object which has no constraintsassociated with it, it will not highlight.


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Constraint Categories

There are two major categories of constraints, Explicit and Inferred.Explicit constraints are constraints that you create by assignment using theconstraints dialog or by virtue of the creation method. Inferred constraintsare Coincident constraints that the system has inferred and createdduring the curve creation process. You have the option to list only Explicitconstraints, only Inferred constraints, or both.

Constraint Listing

The constraints may also be listed in the Show/Remove Constraints dialog byselecting one of the three options at the top of the dialog window.

Selected Object Once an object is selected, the associatedconstraints, depending on the selected constraintcategory, are listed in the dialog. To viewconstraints associated with a different sketchobject, simply select the new object.

Selected Objects Allows the selection of multiple objects; theassociated constraints, depending on the selectedconstraint category, are listed in the dialog. Objectsmay be deselected by holding the shift key downand selecting the object.

All in ActiveSketch

List all the constraints of the active sketch,depending on the selected constraint category.

Listing Box

Any time there are constraints listed in the list box they may be browsed byselecting the constraint to highlight it. When the constraint is highlighted inthe list box, the sketch object(s) that is associated with it is also highlightedin the graphics window. The Step Up the List and Step Down the List buttonsallow easy navigation through the various constraints. The Up and Downarrows on most keyboards will mimic this behavior.


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Sketching

Information

The Information button located on the Show/Remove Constraints dialog willlist all of the constraints in the active sketch to the information window.This is useful should there be a need to make a hard copy of the constraintsor save them as a text file.

Removing Constraints

Constraints may be deleted by these methods:

• Highlight them in the Show/Remove Constraints dialog List box and selectRemove Highlighted Constraint(s), or just double click them in the list.

• Turn on Select Constraints (on the Selection toolbar), select the constraintsymbol on the graphics window, and then choose the Delete icon.

• Turn on Select Constraints, select the constraint symbol on the graphicswindow, and then use MB3→Delete to delete selected constraint.

Undo

Undo from the Edit pull-down menu, the Undo icon on the Standard toolbar,the MB3 pop-up menu, or the accelerator keys. Undo takes the user actionsback one step at a time.

After an Undo is performed, the Redo option is available in the Editpulldown menu or Standard toolbar.

Dragging Geometry

Under constrained geometry can be dragged only when not in a constraintcreation mode. Simply hold down and drag MB1 while on the selectedcurve(s) or point(s).

Selection

When in the Sketcher Task Environment, the selection toolbar changes. Ithas two icons that are only available in the Sketcher.

Select Sketch Objects allows selection of curves and dimensionsin the sketch.

Select Constraints allows selection of constraint symbols in thegraphics window.


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Sketching

Constraint Conditions

When either the Dimensions or Constraints option is chosen, the Status linelists the constraint condition for the active sketch. A sketch may be fullyconstrained, under constrained, or over constrained. When the sketch isunder constrained the Status line will indicate the number of constraintsneeded.

Sketch needs 4 constraintsSketch is fully constrainedSketch contains over constrained geometry

A sketch is evaluated each time a constraint is placed upon the sketch. Eachtime a sketch is evaluated, the system attempts to solve the set of constraintsthat describe how the geometric objects are positioned and their relationshipswith each other.

Fully Constrained

In order to completely capture the design intent of a particular profile, it maybe beneficial to fully constrain the sketch. This occurs when the solver is ableto completely define all sketch geometry.

There is no requirement to fully constrain a sketch. The design intent hasbeen captured sufficiently when the constraint set applied to the profilecauses it to update in the intended manner.

Under Constrained

A sketch is under constrained when there is insufficient information tocompletely locate each sketch point. Degree-of-freedom arrows are displayedat each point that can not be solved to identify the direction in which thatpoint remains free to move.

Over Constrained

A sketch is over constrained when too much constraint information issupplied to the solver. For example, if an Equal Length constraint is appliedto two lines and then dimensions are added to each to constrain their length,the sketch would be over constrained.

The geometry and dimensional constraints that are causing the overconstrained condition are highlighted in a different color to help you identifyand resolve the issue. This color is determined by the Overconstrained Curvesand Dimensions setting in the Sketch Preferences.

An unwanted constraint must be removed before the system will change thegeometric configuration. The sketch remains in the last solved condition.


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Sketching

Conflicting Constraints

Dimensional constraints and geometry that are in conflict in the currentconfiguration with the current constraint set are also highlighted in adifferent color. This indicates that the constraint set that has been supplied isnot solvable with the geometry in its current configuration. Constraints mayneed to be added or removed in order for the sketcher to be able to solve theconstraint set. The highlight color is determined by the Conflicting Curvesand Dimensions setting in the Sketch Preferences.


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Sketching

Activity — Adding Constraints

In this activity you will add constraints to the angle adjustment bracket tocause the expected update to occur when a dimension is modified.



Step 3: Add the required constraints.

Place the cursor over a sketch curve and choose MB3→Edit.



Choose the Constraints icon. (Insert→Constraints)


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Sketching

Select the line (1) at the bottom of the sketch.

Choose Horizontal in the upper left corner of the graphicswindow. (MB3→Horizontal)

This constraint will keep the line from rotating around whendimensions are modified.

There are six places where the curvature transitions need tomaintain tangency.


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Sketching

Select the six tangent curve pairs near the six points shownbelow, two adjacent curves at a time, and apply aTangentconstraint to each pair. Be careful to select on the correct halfof the arc.

Lastly, the two arcs at the top of the slot should remainconcentric.


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Sketching

Select the two upper arcs (1) and apply a Concentric constraint.

The slot should now be constrained such that the angle may beadjusted while the configuration remains as intended.

Choose MB2 to turn the Constraints option off.

Step 4: Edit the dimensions.

Double-click on the 45° dimension and change it to 75°.

The sketch geometry changes in the expected manner.


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Sketching

Step 5: Apply the change to the solid geometry.

Choose the Update Model icon. (Tools→Update Model)




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Sketching

Activity — Constraining a Profile

Constrain the pipe vise sketch to satisfy the stated design intent.

Apply constraints to the curves so that the following may becontrolled:

• The outside envelope of the part.

• The included angle of the angled lines.

• The angled lines must remain centered in the part horizontally.

• The width of the slot at the bottom of the angled lines is controlledby the radius at the bottom of the slot.

Step 1: Open pipevise_1.



Double-click on a sketch curve.

Step 4: View the system applied constraints.

Choose the Show/Remove Constraints icon.(Tools→Constraints→Show/Remove Constraints)

Choose All In Active Sketch in the List Constraints For: areaof the dialog.


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Sketching

Verify the Show Constraints option is set to Explicit.

The system created constraints are now displayed in the listbox. The dialog should look similar to the graphic shown below.

Choose the first constraint in the list.

The object referred to in the list is highlighted in the graphicswindow. There should be one horizontal line highlighted.

Use the UP and DOWN arrow buttons located to the right ofthe list box to browse through the constraint list.

Cancel the Show/Remove Constraints dialog.

Step 5: View the degree of freedom arrows.

Turn on the Constraints icon. (Insert→Constraints)


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Sketching

Notice that there are degree of freedom arrows at each of thesketch points. Even though most of the objects in the sketch haveconstraints associated with them, the sketch points are free tomove in all directions. This is because the system cannot locateany of the points relative to model space.

Step 6: Constrain the location of a point.

Select the lower endpoint of the left vertical line.

Select the vertical datum axis.

Choose the Point on Curve icon in the upper left cornerof the graphics window.

The geometry now changes to follow the constraint. The pointat the bottom of the left vertical line is now constrained in thehorizontal direction.

Select the left endpoint of the bottom horizontal line.


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Sketching

Select the horizontal datum axis.

Choose the Point on Curve icon.

The geometry now changes to follow the new constraint. Theshared sketch point at the bottom of the left vertical line is nowconstrained in both the horizontal and vertical directions. Thedegree of freedom arrows go away and, due to the horizontaland vertical constraints on the lines that share the sketchpoint, one of the arrows on the opposite end of those lines hasdisappeared.

Choose MB2 to cancel the Constraints mode.


Step 7: Move the datum planes and axes to layer 61.

The datums have served their purpose of locating the sketch. Youwill now move them to ease selection of objects and clean up thescreen display.

Choose Edit→Object Display.

Choose the Class Selection icon in the upper left corner of the

graphics window.

Choose Type.


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Sketching

Choose Datums and choose OK.

Choose Select All and OK.

Key in 61 for the Layer in the dialog and press Enter.

Step 8: Continue adding constraints to satisfy the stated design intent.

Turn on the Constraints icon. (Insert→Constraints)

Hold the Ctrl key down and select the two horizontal lines (1)at the top of the profile.

Choose Collinear and Equal Length.

Use the Esc key to deselect all the curves.(Edit→Selection→Deselect All).

Select the right side of the arc at the bottom of the slot (1).Select the short right vertical line (2, but not on the end point).


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Sketching

Choose Tangent.

Create another Tangent constraint on the other side of the slot,selecting the left side of the arc and the left vertical line.

Hold the Ctrl key down and select the bottom horizontal lineand the lower endpoint of the line originating from the arccenter.

Choose Point on Curve.

Choose Midpoint.

Use the Esc key to deselect all the curves.(Edit→Selection→Deselect All).

Select the line (1), shown below, between the midpoint andthe arc center.

Choose Vertical.

Adding dimensional constraints to satisfy the controllingportions of the design intent will allow the profile to be changedby modifying the numerical values.


Select the bottom horizontal line. Drag the dimension toposition it and select with MB1 to place it.


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Sketching

Key in a value of 5 and press Enter.

Notice the curves change color as they become constrained.

Fit the view if necessary.

Select the left vertical line and place the dimension for it.Change the value to 3.75.

Select the top left horizontal line and place the dimension.Change its value to .5.

Fit the view if necessary.

Select the left angled line (1) and the top left horizontal line(2), avoiding the end points. Place the angular dimension andchange its value to 45°.


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Sketching

Select the right angled line and the top right horizontal line,avoiding the end points. Place this angular dimension andchange its value to the ’p’ number assigned to the other angulardimension.

Select the arc at the bottom of the slot. Place the radiusdimension and change its value to .25.

Select the line connecting the arc center and the midpointand place this vertical dimension. Change its value to 1.5 andchoose Enter.

The Status line now informs you that the sketch is fullyconstrained. Remember that it is not necessarily requiredto fully constrain the profile if it is updating in the mannerdesired.


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Sketching

Step 9: Change the constraints on the sketch to alter the included angle inthe notch.

Click on the first angular dimensional constraint that wascreated and change it from a 45° to 30°.

Notice that the depth of the notch is unchanged as a result ofthis edit. Should that have not been our intent, we would haveto constrain the sketch in a different manner.




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Sketching

Activity — Sketching and Constraining a Gasket

In this activity, you will create and constrain a gasket. To efficiently capturethe design intent, constraints and dimensions will be added progressively.

The center hole is the origin of the gasket. The three holes are locatedon a horizontal axis. The lines on the outer boundary of the profileare tangent to the arcs.

Step 1: Open the seedpart_in part and save it as ***_gasket_1 where ***represents your initials.


Step 3: Create the sketch on a Datum CSYS.

Change the Work Layer to 21 so that the part will be compliantwith class standards.


Click on the sketch name; key in s21_profile and press Enter.

Choose Datum CSYS.

Choose Absolute CSYS.

Choose OK.


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Sketching

The X-Y plane of the Datum CSYS is highlighted as the defaultsketch plane.

Choose OK to accept the default plane.

Step 4: Set the Infer Constraint Settings.


Verify that the following constraints are turned on.

ConcentricCoincidentDimensional Constraints

Choose OK.

Step 5: Create the circles in the center of the gasket.


Verify that Control Point is turned on in the Snap Pointtoolbar.

Select the existing point at the origin of the Datum CSYS.


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Sketching

Drag the cursor to preview circle as shown below. Key in aDiameter value of 2 and press Enter.

The first circle is created.

Key in a Diameter value of 3 for the second circle and pressEnter.


Choose MB2.

The two circles are fully constrained because of the dimensionaland geometric constraints that were inferred as you created them.


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Sketching

Step 6: Create a circle representing the hole on the left side.


Click and drag to create a circle near on left side of the graphicswindow. Key in a Diameter value of 0.5 and press Enter.


Select the arc center of the circle and the horizontal datum axis.

Choose Point on Curve .


Create a perpendicular dimension from the vertical datumaxis to the arc center of the left circle. Change the value ofthe dimension to 2.625.

Step 7: Create a circle for the outer boundary on the left side.

Create another circle in the left side of the graphics windowwith a diameter of 1.



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Sketching

Select the two circles on the left side and choose Concentric.

Step 8: Create circles representing the hole and outer boundary on theright side.

Create two circles on the right side of the graphics windowrepresenting the hole and the outer boundary of the gasket. Donot explicitly enter the diameter values. You will constrainthem to be equal to existing circles.


Select the two new circles on the right and choose Concentric.


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Sketching

Select the arc center of the circles on the right and the

horizontal datum axis and choose Point on Curve.

Select the smaller circle on the left and the smaller circle on

the right and choose Equal Radius.

Select the larger circle on the left and the larger circle on the

right and choose Equal Radius.


Create a horizontal dimension from the arc center of the leftcircles to the arc center of the right circles. Change the value ofthe dimension to 5.25.

Step 9: Set the Infer Constraint Settings before creating the lines.


Disable all constraints except Point on Curve and Tangent.

Choose OK.

Step 10: Create the tangent lines on the outer boundary of the gasket.


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Sketching

Choose the Line icon. (Insert→Line)

In the Snap Point toolbar, disable all options except Point on

Curve.

Create the lines by selecting the circles representing the outerboundary of the gasket. Select the circles by placing the cursornear the expected tangency.

You should see Point on Curve and Tangent constraint symbolson each end of the lines as they are created.

The Quick Trim option could be used to trim the circles.However, when extruding the sketch to create a solidbody, it is possible to define the correct boundary of thegasket without trimming.

Step 11: Choose the Finish Sketch icon.

Step 12: Choose File→Close→Save and Close.


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Sketching

Convert To/From Reference

At times it is useful to add a dimension to a sketch to see the effect of achange numerically. Adding a dimensional constraint, however, would causethe sketch to become over constrained. It also may be necessary to addsketch curves to aid in the construction and constraining of a profile withoutrepresenting a portion of the swept feature.

To support these needs, curve and dimensional constraints within a sketchmay be converted to and from a Reference status.

• To convert objects, select them in the graphics window and choose ConvertTo/From Reference from the MB3 pop-up menu.

• You may access a dialog by choosing the Convert To/FromReference icon from the Sketch Constraints toolbar(Tools→Constraints→Convert To/From Reference).

• Reference curves are displayed in a phantom line font and are ignoredduring sweep operations.

• Reference curves and dimensions are displayed in colors specifiedby the Reference Curves and Reference Dimensions settings inPreferences→Sketch→Colors.

• Reference dimensional constraints are displayed with only the valueportion of the expression. The values will be updated as the sketch ischanged, but they do control the sketch geometry with which they areassociated.

Dimensions can be made reference as they are created by choosing

Create Reference Dimension in the icon option bar.


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Sketching

Activity — Constraint Conditions

In this activity, you will constrain and edit a simple sketch to change thedesign intent. This configuration is not one that you would likely sketch, butits simplicity illustrates the concept of an over-constrained condition.

Apply constraints to control the length and width of the sketch. Theshape of the sketch should remain rectangular.

Step 1: Open seedpart_in.


Step 3: Create a sketch on Layer 21.

Change the work layer to 21.


Choose Datum CSYS.

Choose Absolute CSYS.

Choose OK.

The X-Y plane of the Datum CSYS is highlighted as the defaultsketch plane.

Choose OK.


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Sketching


Choose the Infer Constraints Settings icon.(Tools→Constraints→Infer Constraint Settings)

Verify that the following constraints are turned on.

HorizontalVerticalParallelPerpendicularCoincident

Choose OK.

Step 5: Create a rectangle.

Choose the Rectangle icon. (Insert→Rectangle)

Verify that Control Point is turned on in the Snap Pointtoolbar.



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Sketching

Drag the cursor to preview the rectangle and select a cursorlocation near the upper right corner of the graphics window.

Step 6: Interrogate the constraints that currently exist for this sketch.

Choose the Show/Remove Constraints icon.(Tools→Constraints→Show/Remove Constraints)

Choose All In Active Sketch.

Set the Show Constraints to Explicit.

Highlight the first constraint in the list and use the downarrow button to browse the constraints.

Choose Cancel.

Step 7: Apply dimensional constraints to control the length and width ofthe rectangle as per the design intent.


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Sketching


Select the left vertical line and place the dimension. Changethe value to 2.75.

Select the bottom horizontal line and place the dimension.Change the value to 4.5.

As dimensional constraints are being created, thedegree-of-freedom arrows are eliminated and the curves change tothe fully constrained color. The sketch is fully constrained with onevertical and one horizontal dimensional constraint, along with thegeometric constraints inferred when the lines were constructed.

Design Change — Modify the sketch so that it can becontrolled by the angle and length of a diagonal line.

Step 8: Create a diagonal line in the sketch and convert it to reference.

Choose the Line icon. (Insert→Line)

In the Snap Point toolbar, disable all options except Control

Point.

Select the lower left endpoint and the upper right endpoint ofthe rectangle to define the line.

Step 9: Convert the diagonal line to Reference status.


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Sketching

Choose MB2 to exit the line creation mode.

Select the diagonal line.

Choose MB3→Convert To/From Reference.

Step 10: Apply an angular dimensional constraint.


Select the lower horizontal line (not the endpoint) and thediagonal line (not the endpoint). Indicate a location for theangular dimension and change the value to 35°.

The Status line indicates that sketch is now over constrained.The sketch objects associated with the over constrainedcondition change to the color specified by the OverconstrainedCurves and Dimensions setting in the Sketch Preferences.

To correct the over constrained condition, one or more of theoffending constraints must by removed. The new design intentis to control the sketch with angular and diagonal lengthdimensions.


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Sketching

Step 11: Apply a parallel dimensional constraint.

Select the diagonal line and place a parallel dimension. Changethe value of the dimension to 6.5.

Notice that the sketch configuration does not change when thevalue is modified. The system leaves the geometry in its lastsolved state until the over constrained condition is resolved.

Step 12: Convert sketch dimensions to reference.

Choose MB2 to exit the dimension creation mode.

Select the horizontal and vertical dimensions.

Choose MB3→Convert To/From Reference.

The sketch is returned to a fully constrained condition. Thereference dimensions reflect the value only. They do not controlthe geometry to which they are attached.

The over constrained condition could also have been resolvedby deleting the horizontal and vertical dimensions.




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Sketching

SummaryThis lesson introduced the concept of sketch creation.

Sketches may be used to define a base feature, guide paths, and additionalassociative features to the base feature.

A sketch parametrically controls curves. It can also be defined on a sketchplane which is associative to a datum plane/face of a model. Both of thesebenefits allow you to capture and maintain design intent.

Constraints are applied to sketch objects in order to capture the design intent.The level of constraint, partial or full, is determined by the design intentand what is necessary to capture it.

In this lesson you:

• Created sketches on datum planes, solid faces, and a Datum CSYS.

• Created freehand curves in a sketch.

• Created and edited dimensional constraints.

• Created inferred and explicit geometric constraints.

• Converted sketch curves and dimensions to reference status.


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Lesson

2 Constraining Sketches

Purpose

This lesson describes creating and modifying sketch constraints.

Objectives


• Create Geometric Constraints

• Work with System Applied Constraints

• Auto Create and Display Constraints

• Work with Constraint Conditions

• Convert Sketch Curves To Reference Curves

• Update The Model

• Add Objects to Sketch

• Constrain the Perimeter of a Sketch


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Constraining Sketches

Constraints

NX provides a variety of feedback about a sketch.

You can see color coded information about the constraint condition of a curve,list current constraints, or view information about how many constraints areneeded to fully constrain the sketch.

DragYou might consider a sketch sufficiently constrained, but the system stilllists the status as under constrained.

One method of interrogating the sketch is to drag the geometry. Draggingallows under constrained geometry to be moved in the unconstraineddirections.

To drag a single curve or point move the cursor over it, click, and drag. Formultiple objects first select curves or end points and then click and dragall selected objects. Objects that share sketch points with the object beingdragged remain connected to the object and stretch to accommodate themovement.

If an object has no freedom to move due to constraints, it will not drag.

In the example below, L6 (1) is being dragged while L4 and L5 (2) stretch toaccommodate the movement of the line. L6 is constrained so it maintains itsangular and length relationship during the drag operation.


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Drag may be used to drag multiple sketch curves. Select the curves to bedragged, then use the left mouse button to click and drag to move the objectsin their unconstrained directions. Selecting two or more objects to dragcauses different results as the constraints applied to different curves havedifferent effects on how the group of curves react.

In the example below, the two lines L4 and L6 (1) are selected to drag causingL5 and the upper horizontal line (2) to stretch.

Drag may be used to drag a single sketch point. Move the cursor topre-highlight the point, then click and drag to move it in its unconstraineddirections. Objects that share the sketch point stretch to accommodate themovement.


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In the example below, the sketch point V1 is being dragged. The lines thatshare the sketch point stretch to accommodate the movement of the point.Their angle and length are modified by the drag operation.

Drag may also be used to approximate the correct location of a sketch profilerelative to other objects. This may be useful when the process of constrainingdistorts the sketch profile so that it would be difficult to undo.

Undesired Results

Distortion caused by the act of constraining.

Desired Results

Desired results when entire profile dragged from quadrant to quadrant.


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Create Inferred ConstraintsCreate Inferred Constraints lets you toggle inferred constraints on or off asyou create and/or edit sketch geometry.

Create Inferred Constraints is active by default. The icon is available (but bydefault not displayed) in the Sketch Constraints toolbar.

When you drag a sketch object you can make use of Inferred Constraints,such as horizontal or vertical.

If Create Inferred Constraints is inactive (off), the system uses the constraintsonly to place the geometry, but does not store the constraints in your file.

If Create Inferred constraints is active (on), the system creates and storesconstraints as shown by constraint symbols you see on the screen.

You control which constraints can be inferred during curvecreation via Inferred Constraint Settings.


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Activity - Dragging Sketch ObjectsStep 1: Open the part file drag_1.


Choose Start→Modeling.


Zoom out the view to give yourself some working room aroundthe geometry.

Toggle Show All Constraints to active.

In Preferences→Sketch make sure that Dynamic ConstraintDisplay is inactive (off).

Notice that the constraint set is presently made up of one verticaland several tangent and coincident constraints.

Step 3: Drag a curve.

Place the cursor over the curve at location (1) shown below.Hold MB1 down and drag the curve to location (2).


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Notice how the vertical and tangent constraints impacted the dragoperation. Also notice the circle was left behind.

Choose Undo.

Choose Constraints.

Select the arc (1) and circle (2) shown below. Apply a

Concentric constraint.

Toggle Constraints off (or MB2).


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Notice that the circle moved with the drag operation.

Choose Undo.

Step 4: Dragging curves versus endpoints.


The line with a constraint remains tangent to the arc, while theother line may not remain tangent.

Choose Undo.


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Select and drag the endpoint shown below from location (1)to (2).

When you select an end point the radius of the arc changesdramatically as you drag. You are effectively dragging the radiusalong with the end point.

Choose Undo.

Step 5: Drag a line to horizontal, and create a horizontal constraint.

Display Create Inferred Constraints in the SketchConstraints toolbar, or use Tools→Constraints.

Verify that Create Inferred Constraints is active.


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Drag the endpoint (1) shown below from location (1) to (2).End the dragging action only when you can see a horizontalconstraint symbol.

Notice that the line snaps to horizontal within the snap angle.

Notice also that the horizontal constraint becomes permanentwhen you release the end point you were dragging.

Choose Undo.


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Step 6: Drag a line to horizontal without creating a constraint.

Toggle Create Inferred Constraints to inactive.

Once again, drag the endpoint from location (1) to (2). End thedragging action only when you can see a horizontal constraintsymbol.

Notice that, just as before, the line snaps to horizontal within thesnap angle and the horizontal symbol appears.

Notice that this time no horizontal constraint is created.

Choose Undo.

Toggle Create Inferred Constraints to active. (Restore thedefault setting.)


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Step 7: Drag several curves at one time.

Select the curves shown below by dragging a rectangle aroundthem.

Drag the selection to the left as shown below.


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Step 8: Drag all of the sketch geometry to a new position.

Drag a rectangle around the entire sketch and drag thegeometry to the location shown below.

Step 9: Locate the sketch.

Choose Constraints.

Select the arc center of the arc (1) and the horizontal datumaxis (2).

Apply a Point on Curve constraint.


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Select the same arc center and the vertical datum axis.

Apply a Point on Curve constraint.

Notice what happened to the sketch geometry. The arc centermoved to the prescribed location and the vertical line stillmeets the vertical and tangent constraints assigned to it.

Toggle Constraints off (or MB2).

Fix the geometry by dragging the vertical line to the other sideof the arc. Try to maintain the same size of the upper andlower arcs.

Choose Finish Sketch.



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Activity - Adding ConstraintsAs a design evolves two angles that determine the extents of acircular slot may be changed.

When changes are made, the update must not fail, and the followingconditions must be met:

• When the angles change, it is necessary that the slot retain itscurrent width.

• The slot must remain centered in the arm with its upper endconcentric with the end of the arm.

• All arcs that are currently tangent must remain tangent.

You will verify that this sketch needs additional constraints to controlit as it updates.

You will add enough geometric constraints to fully capture the designintent.

Step 1: Open angle_adj_4 and choose Start→Modeling.


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Step 2: Examine the sketch.


If necessary, toggle Show All Constraints to active.

In Preferences→Sketch, if necessary, toggle DynamicConstraint Display to inactive.

Are there any geometric constraints in the sketch?

What do you think would happen if you edited one of thedimensions?


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Step 3: Edit the angle p68 to 35 and observe the update behavior.

Double-click on p68 to enter edit mode.

Change the value to 35 and press enter.


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What happens to the sketch?

The unite between the shape extruded from the sketch and the restof the model will fail, thus the model cannot update successfullywith the sketch in this condition.

In addition, one of the end arcs of the slot has lost its tangency.

Step 4: Drag a curve end to see if the sketch deforms.

Drag the end point indicated by the square dot in the directionof the black arrow.


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Step 5: Undo the changes.

Choose Edit→Undo List and choose Edit Sketch Dimension,the entry just above Enter Sketcher.

You could also press Ctrl+Z until all of the edits you madeare undone

Step 6: Constrain the line adjacent to the part.

Choose Constraints.

Select the line (1) at the bottom of the sketch.

Select the solid edge behind the line.

Choose Collinear.

This constraint will keep the line from rotating around whendimensions are modified.


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Step 7: Constrain the arcs to maintain tangency in six places.

Select the six tangent curve pairs near the six points shownbelow, two adjacent curves at a time, and apply Tangentconstraints to each pair. Be careful to select on the correct halfof the arc.


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Step 8: Make the two arcs at the top of the slot concentric.

Select the two upper arcs and apply a Concentric constraint.

The slot should now be constrained such that the angle may beadjusted while the configuration remains as intended.

Choose MB2 to toggle the Constraints icon off.

Step 9: Edit the p68 dimension to 75.

Double-click on the 45° dimension and change it to 75°.

Step 10: Apply the change to the solid geometry.

Choose Finish.



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Automatic Constraint CreationThe system can create certain types of constraints automatically. This isespecially useful when geometry is added to a sketch rather than createdas sketch objects.

You can enable the Automatic Constraints icon on the Sketch constraintstoolbar, or use Tools→Constraints→Automatic Constraints.

Procedure

1. Choose Automatic Constraint Creation.

2. Toggle the desired constraints to on.

3. Ensure that the proper distance and angle tolerances are set.

4. Choose Apply or OK.

The Set and Clear buttons, on the Auto Create Constraints dialog, may beused to turn all of the constraint fields on or off.

When using the horizontal, vertical, parallel, and perpendicular auto createoptions, the system evaluates lines using the specified Angle tolerance toapply the proper constraints.

Other types of auto create constraints, such as coincident and concentric, usethe Distance tolerance to apply the constraints.

Using the Distance tolerance with the Coincident constraint will have theeffect of closing gaps. This condition is common with objects that have beentranslated from other systems.

Allow Remote constraints permits automatic constraints to be createdbetween curves that do not actually touch. Currently, tangency betweencurves that would be tangent if they were extended is supported.


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Sketch Operations — ProjectProject lets you create extracted curves or strings of curves by projectingexternal objects onto a sketch along the normal of the sketch plane. You canproject a curve associatively or non-associatively onto a sketch.

Objects available for projection include:

• Curves, associative and non-associative

• Edges

• Faces (selecting a face automatically selects its edges for projection)

• Other sketches or the curves within the sketches

• Points

Procedure

1. Set the selection filter to the desired object type.

2. Select a curve string, face, edges or points you want to project onto thesketch plane.

3. Set the Associate option as desired.

4. Set the Output Type option as desired.

5. Click OK.

A curve string is projected onto the sketch plane from the selected curves,face or edges. If you selected points, the points are projected onto thesketch.


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Output Types

Original The extracted curves are created with their originalgeometry types.

SplineSegment

The extracted curves are represented by individualsplines.

SingleSpline

The extracted curves are connected andrepresented by a single spline

Editing Projected Curves

You can add, remove, or replace curves projected into a sketch by displayingand using the Edit Curve icon on the Sketch Operations toolbar, or Edit→EditCurve. You cannot edit projected points.

When you choose Edit Curve and select a non-associated projected curvestring, the normal edit curve dialog displays.

Editing an associated projected curve string displays the Project options.


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Activity - Projecting Objects into a SketchYou have a part that was translated from another system. It isnecessary to use the imported curves to create an extrude body.

You will:

• add the curves to a sketch.

• repair objects that are not suitable.

• create enough constraints to make the geometry usable with theextrude function.

Step 1: Open iges_1 and if necessary choose Start→Modeling.

Step 2: Create sketch s21_profile on layer 21.

Change the Work Layer to 21.

Choose Sketch.

Click on the sketch name; key in s21_profile and press Enter.

Choose OK to accept the XC-YC plane.


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Step 3: Verify whether or not the existing curves lie on the sketch plane.

Imported curves should always be checked for being planarand for gaps at “adjacent” end points.

Choose Analysis→Distance.

Alternately select the sketch datum plane and points onvarious lines and arcs.

Do the curves lie on the sketch plane?

If the distance between any point on a curve and thesketch plane is not zero, then that curve does not lie onthe sketch plane.

Step 4: Add the existing curves to the sketch.

Fit the view.

If necessary display the Sketch Operations toolbar.

If necessary, use Add or Remove buttons to display the Projecticon.

Choose Project.

If necessary, toggle Associative to inactive.

Associative sketch curves are constrained automatically bythe curves they were projected from. You will not be ableto alter their constraint condition from inside the sketch.

When you project curves associatively they are treated asa single feature.

You will need to access the curves individually, so you donot want associative projection.

Press the key combination Ctrl+A (Select All).

Choose OK to add the curves.

Step 5: Verify the types of curves that were created.


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If imported curves are not parallel with the sketch plane,arcs may become conic curves.

It is also prudent to verify that imported curves thatappear to be lines or arcs are not in fact splines.

Move the cursor over the entire string of curves while observingthe status line.

What curve type is the curve shown below?

Step 6: Remove the conic curve.

Make layer 41 invisible.

Move the cursor over the highlighted curve shown below sothat it prehighlights, press and hold MB3 until the radialpopup icons appear, and slide to the left over the delete icon. .

Step 7: Create an arc to replace the conic.


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Choose Arc.

Make sure End Point is enabled on the Snap Point toolbar.

Indicate the two end points in the order shown.

For the third point, indicate any point that creates an inferredtangency constraint at one end of the arc.

Click MB2 to exit from arc creation.


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Step 8: Analyze the curves.

Choose Analysis→Distance.

Select pairs of endpoints from several adjacent curves, anyplace where there is not a coincident symbol.

Make sure that Point on Curve is inactive on the snappoint toolbar.

End Point is the only necessary option.

Notice that the curves are not contiguous. This is common whengeometry is translated into a double precision system, like NX,from a single precision system. These values are fractions of amillimeter in this case; however, trying to extrude these curvesinto a solid body will fail because of gaps and overlaps.

Cancel from Analysis.

Display the Automatic Constraints Creation icon on theSketch Constraints toolbar, or use Tools→Constraints.


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Step 9: Close the gaps between the curves.

Choose Automatic Constraints Creation.

Choose the Clear button to clear all constraint types.

Choose the Coincident constraint to toggle it to active.

Change the Distance tolerance value to .25.

Choose OK to create the constraints.

NX interrogates each sketch point for other sketch points withinthe Distance tolerance and combines the points to one.

Observe the display of coincident constraints that were added.

The profile will now extrude properly to create a solid body.



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Step 10: Extrude the sketch into a solid feature.

Orient the view to Trimetric. (HOME key.)

Move the cursor over any sketch curve until it prehighlights.

Hold MB3 until the radial pop-ups appear, and slide right to

choose Extrude.

NX treats sketches as collective strings of curves for swept features.

Enter an End distance of 200 mm.

Enter a Start distance of 50 mm.

Choose OK to create the body.

Fit the view.

The solid body is created.

Additional sketch constraints can now be added to capturedesign intent. The body will update when you chooseUpdate Model or Finish.

Step 11: Optional challenge: You saw that the sketch does not have to befully constrained to be extruded.

Now, optionally, add all tangent constraints and any others neededto fully constrain the sketch.



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Activity - Auto Creating ConstraintsYou can use auto constraint creation to quickly create or recreate mostconstraints in a reasonably accurate sketch.

In this part, you will pretend that there is an obscure problem withconstraints that someone else has created. Since the sketch is fairlysimple, you decide to remove all constraints and replace them withnew ones.

Auto Constraint Creation will save a lot of time and effort as youcomplete your goal.

Step 1: Open the part.

Open pipevise and choose Start→Modeling.



Step 3: Analyze the existing constraint set.

Ensure Show all Constraints is toggled to active.

Choose the Show/Remove Constraints icon.


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Ensure the radio button for All In Active Sketch is active.

Change the Show Constraints option to Both.

Notice the different types of Explicit and Inferred constraintsthat exist in this part.

Step 4: Remove the constraints.

Select Remove Listed.

Choose OK.


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Step 5: Selectively Auto Create the constraints.

Choose Automatic Constraint Creation.

Choose the Clear button in the All Constraints area of thedialog.

Toggle on the buttons for Horizontal, Vertical, Coincident, andTangent only.

Check or ensure that the Distance Tolerance is .001.

Choose OK to create the constraints.

Step 6: Manually create the rest of the constraints.

Choose Constraints.

Select the left-most vertical line.

Select the vertical datum axis.

Choose Collinear.

Select the bottom horizontal line.

Select the horizontal datum axis.

Choose Collinear.

Hold the Ctrl key down and select the two horizontal lines atthe top of the profile.

Choose Collinear and Equal Length.

If necessary, display the Deselect All icon on theSelection toolbar.

Choose Deselect All .


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Hold the Ctrl key down and select the bottom end point ofthe vertical line controlling the slot location and the bottomhorizontal line.

Choose Midpoint and Point on Curve.

The Status line should now inform you that the sketch is fullyconstrained.

Click MB2 to exit the function.

Windows users may also use the ESC key.

Choose Finish.

The sketch is now fully constrained.



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Add Existing Curves to a SketchIf you initially decide not to control a swept feature with a sketch, or if youobtain a wireframe part from a translator, you may create a sketch andadd the geometry to it at a later date. You do this by displaying and usingAdd Existing Curves on the Sketch Constraints toolbar, or Insert→ExistingCurves.

An example could be that you have a general idea of what a cross sectionalprofile looks like, but do not quite understand how form, fit, and functionof the part will drive the design intent. As the design matures and yourecognize the intent, you may then create a sketch and add already sweptcurve geometry to it.

Curves that are added to a sketch have their layer reassigned to that of thesketch.

The only constraints that will be applied to Existing Curves that areadded to a sketch are Inferred Coincidence, regardless of how thecurves were originally created.

Associative curves may not be directly added to sketches. The shape ofthese curves are controlled by other means, such as the associative faces forprojected points or curves, or the law functions that control certain typesof splines and helices.


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Activity - Adding and Constraining CurvesApply dimensions and constraints to control the following:

• The width of the slot (1).

• The total length of the slot (2).

Step 1: Open straightslot_1 and choose Start→Modeling.

Step 2: Create a sketch in layer 21.

Make 21 the Work Layer.

Choose Sketch.

Click on the sketch name; key in s21_slot and press Enter.

Select the front face (1) as the sketch plane.

Select the horizontal sketch axis (2) as shown above.


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Choose OK.

Step 3: Add the curves to the sketch.

Display the Add Existing Curves icon in the SketchOperations toolbar, or use Insert→Existing Curves.

Choose Add Existing Curves.

Press the key combination Ctrl+A and then choose OK.

Step 4: List the constraints currently on the sketch.

Choose Show/Remove Constraints.

Ensure the radio button for All In Active Sketch is toggled on.

There are four inferred coincident constraints.

No explicit constraints exist in this sketch because the curveswere added to the sketch and not created with the sketch active.

Cancel the Show/Remove Constraints dialog.


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Step 5: Fully constrain the sketch according to the design intent.

Use dimensions to locate the left arc center 1 inch from the leftside of the part and 2 inches from the bottom of the part.

Add the following constraints:

Horizontal constraint to both lines

Tangent constraint to arcs and lines (4 places)

Remember Automatic Constraints.

Add the following dimensions:

Step 6: After constraining the sketch, edit the dimensions for the slot toensure that it updates properly. Use any reasonable values of yourchoice.



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Activity - Design ChangeChange the design intent on the previous sketch: modify dimensionsand constraints so that one end may be made larger than the other(1, 2).

The total length (3) still needs to be controlled. Examine the diagrambelow and follow the steps to perform the design change.

Step 1: Open straightslot_2 and if necessary choose Start→Modeling.

Step 2: Double-click on any sketch curve to activate the sketch.

Step 3: Identify and delete constraints that do not meet the new designintent, and add new constraints.

Select the Show/Remove Constraints icon.

Verify the radio button for All In Active Sketch is selected.

Delete the horizontal constraints.

Delete the slot width dimension and replace it with a radiusdimension on each arc.

The sketch is not fully constrained but it does meet the designintent; one end may be made larger than the other.

Step 4: Edit the dimensions for the slot to ensure it updates properly.

Assign a value of .5 to the left radius dimension.

Assign a value of .25 to the right radius dimension.

Choose Finish Sketch and close the part.


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Activity - Another Design ChangeChange the sketch design so that it may be oriented at various angles(1) other than horizontal. The total length of the shape should still becontrolled.

Step 1: Open straightslot_3 and if necessary choose Start→Modeling.

Step 2: Double-click on any sketch curve to activate the sketch.


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Step 3: Create reference geometry.

Check your Snap Point settings to assure Arc Center isactive.

Create a line (1) from arc center to arc center.

Create another line (2) and apply Vertical (if necessary) andConstant Length constraints.

Exit from constraint creation.

Step 4: Converting Curves to Reference Lines.

Select the two lines just created.

Hold MB3 over either one of the lines until the radial popupoptions appear.

Slide to the right and down to choose Convert To/From

Reference.


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Step 5: Add or edit dimensions as shown below.

If a horizontal dimension for the slot length was inferredor manually defined, delete it and replace with a paralleldimension.

Step 6: After constraining the sketch, edit the dimensions for the slot toensure that it updates properly. Use any reasonable values of yourchoice.



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Activity - Constraining the Perimeter of a SketchThe design intent for swimming pool requires that:

• The two larger radii are equal and must be controlled by adimension.

• The four corner radii are equal and must be controlled by adimension.

• The perimeter must be a constant value.

Step 1: Open the part file skt_perimeter and choose Start→Modeling.

Step 2: Activate the SWIMMING_POOL sketch.


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Step 3: Investigate the existing constraints using Show/RemoveConstraints.


If necessary, toggle on All in Active Sketch.

Verify the Constraint Type is set to All.

Verify the Show Constraints option is set to Explicit.

Choose the first constraint in the list, A5 Equal radius to A7.Investigate the highlighted curves on the screen.

Select the Step Down the List button or use your down arrowkey and read through the constraints to get an idea of theexisting constraints in the sketch. Then Cancel the dialog.


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Step 4: Add the two dimensions shown.


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Step 5: Constrain the perimeter of the sketch.

Choose the Perimeter icon from the dimension pull-downicon.

Select all of the active curves, a total of eight.

Choose the Sketch Dimensions Dialog icon.

Choose MB2 to create a perimeter dimension for the selectedcurves.

Verify that a Perimeter dimension appears in the Dimensionslist. (It may be a different "p"-number.)

If you did not get all of the curves selected, highlight theperimeter constraint in the Dimensions list and choose theDelete button in the dialog.


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Step 6: Edit the perimeter.

Slide the slider bar to the left and right and observe thechanges in the sketch.

Edit the Perimeter and other dimensions by entering valuesand/or using the slider bar.



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Activity - Controlling Heat Transfer in a Cooling PipeThe design intent for cooling fins on a length of pipe requires that thecross sectional area of the fins should be controlled by the volume offluid in the pipe. Each fin’s perimeter should equal 1.25 times thecross sectional flow area.

You will:

• Use a perimeter dimension to control the total perimeter.

• Equate the expression for the perimeter to 1.25 times the crosssectional area of the pipe.

Step 1: Open the part file perim_1 and if necessary choose Start→Modeling.

This part contains the following features:

Cylinder

Thru Hole - The diameter of the thru hole controls the diameter ofthe cylinder by maintaining a constant wall thickness.

Sketch

Using Tools→Expressions, examine the areaRatioexpression.


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Step 2: Interrogate the sketch.

Activate the FIN sketch.

Fit the view.

The sketch is located by two constraints. The reference curve anddatum plane (layer 61) are collinear (1) and the sketch arc and ODof the cylinder feature are concentric (2).

The sketch is not yet totally constrained.


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Step 3: Add a perimeter dimension to the sketch.

Make layer 1 invisible.

Choose the Perimeter icon from the dimension pull-downicon.

Choose the Sketch Dimensions Dialog icon.

Individually select the curves shown below.

Click MB2 to create the perimeter dimension.

Note that there is a new dimension called Perimeter_p## and thatthe sketch is now fully constrained.

Choose Close.

You cannot edit the curves of a Perimeter constraint.

If you miss a curve or get an extra, delete the constraintby highlighting it in the Dimensions list and choosing theDelete button in the dialog.

Choose Finish.


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Step 4: Extrude the sketch.

Hold MB3 over a sketch curve until the radial pop up optionsappear.

Slide to the right to choose Extrude.

The default extrude direction is normal to the plane of the sketch,ZC+ in this case.

Double-click the direction vector arrow to reverse the extrusionvector to the negative ZC direction.

Change the Boolean to Unite.

Notice that since there is only one body available as atarget, the system does not require you to select it.


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Use MB3 over the End symbol to change the option to UntilExtended.

You choose Until Extended so that the system knows theface you will select must be extended beyond its currentboundary to trim the extruded sketch.


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Select the bottom planar face of the solid (1).

Choose OK.

Step 5: Create a circular array of the extruded fin.

Make layer 61 Selectable.

Choose Insert→ Associative Copy→ Instance.

Choose Circular Array.

Select the Extrude feature and choose OK.

Enter:

Number = 8Angle = 360/8

Choose OK.

Choose Datum Axis.

Select the datum axis in the graphic window.

Choose Yes.

Choose Cancel.


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Make all but the work layer invisible.

Step 6: Capture the design intent for the fin.


If necessary choose More Options.

If necessary change the Listed Expressions option until ID islisted.

Select the ID (SIMPLE_HOLE(1) Diameter) expression and

change it to 4 and Accept Edit.

Choose Apply.


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Fit the view.

Notice that the fins have retained their original profile. Ifthe cooling pipe’s volume is going to increase the coolingfins will also need to increase.

Recall that an expression, areaRatio, relates each fin’sprofile to the cross sectional flow area.

This expression is associative to the hole feature and willupdate automatically.

You need to link this value to the perimeter constraint.

Undo the last expression operation to return the heatpipe to its original configuration.

Select the expression called Perimeter_p3 (FIN:SKETCH(5)Perimeter Dimension) (the digit following the _p in yourexpression may be different).

Change the Formula to areaRatio and Accept Edit.

While editing the ID expression highlight areaRatio inthe list. Use MB3 → Copy Name to assure that thespelling is correct, then type the rest of the expression.

Choose Apply.

The fins become slightly smaller.

In a real life situation you might tweak the formula until the ratioexactly matches cooling requirements.

Select the ID expression, change it to 4, and Accept Edit.


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Choose OK.

Fit the view.

Notice how the fins have updated to meet the new flowrequirement.



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SummarySketch constraints allow you to capture and maintain design intent evenafter design changes occur. Through dimensions and constraints, you canadapt your solid models to the design intent of the final product.

In this lesson you:

• Applied Design Intent.

• Created Geometric Constraints.

• Auto Created Constraints.

• Displayed Constraints.

• Converted Sketch Curves To Reference Curves.

• Updated a Model.

• Added Objects to a Sketch.

• Constrained a Sketch by its perimeter.


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Lesson

3 Constraint Management

Purpose

This lesson describes other constraint management tools as well as additionalways to use sketches.

Objectives


• Create an Alternate Solution

• Reorder sketches

• Position Sketches on a Solid Body

• Locate a Sketch with Constraints

• Move a sketch using Reattach

• Mirror a sketch


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Constraint Management

Alternate SolutionConstraint sets may be valid in one or more configurations depending on thegiven geometry. Scalar dimensions have no positive or negative sign, theyspecify only an absolute value. This absolute value may be applied to specifya given distance between objects in one direction or the other.

There are times when multiple solutions may be available for a givenconstraint set. At these times there is a need to ask the system to changethe configuration based on the given set of constraints. NX provides thisfunctionality as an Alternate Solution.

Selecting the Alternate Solution icon from the Sketch Constraints toolbar willbring up a small dialog containing the options OK, Back, or Cancel. The Cueline prompts the user to "Select a dimension or circle/arc".

One alternate solution as it applies to a dimension would be the fairly simplecase illustrated below. Constraints for horizontal and vertical have beenapplied to the appropriate lines, as well as collinearity between the twohorizontal segments as shown. The dimension is selected for an alternatesolution with the results as shown. The vertical dimension is valid in eithercase when it is applied as an absolute value.


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A second form of alternate solution can be applied to a circle or an arc, forexample when two circles are constrained tangent to each other or a line isconstrained tangent to an arc. This is illustrated below. In the case of thetwo circles, either solution is valid given the constraints supplied. AlternateSolution may be used to switch between the two if some other constraintcauses the system to select the wrong configuration.

Two Tangent Circles

Select the large circle (1) first and the small circle (2) second.

Line Tangent to an Arc

Select the arc (1) first and the horizontal line (2) second.


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Activity - Alternate Solution

In this activity you will explore alternate solutions to constraint sets and theeffects that different constraints have as they are applied.

Step 1: Open alternate_1.

Step 2: View the constraints.



If necessary toggle Show All Constraints to active and makesure Dynamic Constraint Display is inactive.


Ensure the List Constraints for radio button is set to All InActive Sketch.


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Change the Constraint Type to Tangent.

Select A1 Tangent to L6 to see the only tangent constraint inthe sketch.

Choose Cancel.


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Step 3: Add dimensions.

Choose the Inferred Dimensions icon.

Select the bottom horizontal line and place a horizontaldimension on the screen.

Select the circle and place a radius dimension on the screen.


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Step 4: Obtain an Alternate Solution.

Display the Alternate Solution iconon the Sketch Constraints toolbar.Optionally, you can use the Tools→Constraintsmenu.

Choose the Alternate Solution icon.

The Cue line prompts you to "Select a dimension or circle/arc".

Select the circle and the center vertical line.

The circle flips to the other side of the line. This is a valid alternatesolution, the circle is still tangent to the line.


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Step 5: Obtain another Alternate Solution.

Select the circle and the center horizontal line.

Since there is no constraint associated to the two objects selected,there is no alternate solution available. NX displays a messagestating that there is no valid alternate solution for the selectedobjects.

Choose OK to dismiss the message.

Choose Cancel in the Alternate Solution dialog.

Step 6: Add a Tangency constraint.

Choose the Constraints icon.


Apply a Tangent constraint.


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Choose Alternate Solution.


Here’s what happened. The center horizontal line has sixconstraints associated to it:

HorizontalTangent to the arcLeft endpoint is located midpoint of the left vertical line.Left endpoint is located on the left vertical line.Right endpoint is located midpoint of the right vertical line.Right endpoint is located on the right vertical line.

When the alternate solution is applied to the line and circle, thetop horizontal line collapses onto the bottom horizontal line. Thetwo vertical lines now have a theoretical length of 0 (zero), whichallows the middle horizontal line to meet its midpoint, point oncurve, and tangent constraints.

Choose Undo to restore the geometry.

Step 8: Add constraints to the center horizontal and vertical lines.

Choose the Constraints icon.

Select the left vertical line and the bottom horizontal line and

apply an Equal Length constraint to them.


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Choose Alternate Solution.


With the addition of the Equal Length constraint, the geometrynow updates in the desired manner.




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Placing Sketches Where They Are NeededSketches require a placement plane, which can be a solid face or a datumplane.

Sketches may be located in their plane by constraints with datum axes, datumplanes, objects belonging to other sketches, non-sketch curves, or solid edges.

Only features that are earlier in the Timestamp order (have a lower timestamp number) may be selected to constrain a sketch.

Sketches may be located by one of two methods:

• Sketch constraints (dimensional and geometric)

• Positioning dimensions

These two methods are mutually exclusive.

If you use Positioning Dimensions, you cannot reference externalobjects when creating Dimensions or Constraints.

If you reference external objects when creating Dimensions orConstraints, then you cannot use Positioning Dimensions.

Positioning is supported by the sketcher primarily to permit sketchesto be used in User Defined Features.


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Activity - Creating and Positioning a SketchThe function of this part requires a triangular pocket located relativeto an angled face. The sketch position should update automaticallyif the angle of the face changes.

Step 1: Open fence_1.

Step 2: Choose Start→Modeling.

Step 3: Make layer 21 the Work Layer.

Step 4: Create a sketch of the pocket.

Choose Sketch.

Click on the sketch name, key in s21_pocket and press Enter.

Select the larger top face of the block as the sketch plane.


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Select the upper half of the angled edge of the pad as thehorizontal sketch axis.

You assure that the positive direction of XC will point away fromthe “more pointed” end of the pad by selecting the edge at the endshown below.

You can reverse the direction by double-clicking the headof the x-axis vector.

Choose OK.

If your display does not look like the graphic below, start over(choose File→Close→Reopen Selected Parts).

Blend features are more intuitively edited as blends thanas sketch curves. You will define the shape of the pocket inthis sketch with only three lines, and add the corner radiiof the pocket later using blends.


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The sketcher is automatically in profile mode as you start a newsketch.

Display the Create Inferred Constraints icon in the SketchConstraints toolbar. Alternatively, you may use theTools→Constraints menu.

Toggle Create Inferred Constraints to inactive. (off)

In the middle of the placement face, create the three lines asshown below.

Length values are approximate.

Allow the first line to snap to horizontal.

Allow the second line to snap to vertical.


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Be sure to snap the third end point to the starting point of thefirst line.

Step 5: List the current constraints.

Choose Show/Remove Constraints.

Ensure List Constraints for is set to All in Active Sketch,Constraint Type is set to All, and Show Constraints is set toBoth.

There should be no constraints, because Create InferredConstraints was inactive when you created the lines.

Choose Cancel.

Step 6: Add geometric constraints.

Add coincident constraints only, using automatic constraints.


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Add a perpendicular constraint between the two lines shown.

Add a parallel constraint between the “horizontal” line and thelong edge of the pad, as shown.

Step 7: Add dimensional constraints.

By design, the size of the pocket should be controlled bydefining the lengths of the “horizontal” and “vertical” sides.

Choose Parallel.

Select the horizontal line and place the dimension.

Change the value to 6 and press Enter.

Select the vertical line and place the dimension.


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Step 8: Extrude the sketch.

Hold down MB3 to open the radial pop up menu over any ofthe sketch curves.

Slide right to choose Extrude.

Extrude the sketch to a depth of 1 inch and subtract it to createa pocket.

Step 9: Add a .5 inch blend to the inside pocket corners.

Step 10: Constrain the sketch position.

Locate the sketch .75 inch away from the pad.


Choose Fit.

Choose Perpendicular.


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Create the dimension from the horizontal sketch line to theedge of the solid (1) shown below.

Locate the 90 degree corner of the pocket 1 inch from theedge of the part shown below.

Select the edge at the edge of the part (1) as shown.

Select an end point at the 90° corner.

Use a cursor location to place the dimension.

Enter a value of 1 and press the Enter key.

The sketch automatically moves into position.


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Notice that all three sketch curves change to the fully constrainedcolor, and the status line reports that the sketch is fullyconstrained.

Choose Finish Sketch .

Review the updated model.

Step 11: Verify the sketch positioning by editing the angle of the pad.


The pad has been positioned relative to the block. Itsangle may be changed by editing an expression namedfence_angle.

Change the value for fence_angle to –35, press Enter andchoose OK.

Note that the sketch remains parallel to the pad, .75 inch away,and remains 1 inch from the back of the part.

In some cases if the edit to an edge used to positionthe sketch is great enough, an Alternate Solution to adimension may occur. If either of the locating dimensionsflips, perform an Alternate Solution on the applicabledimension to resolve the flip.



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Activity - Positioning a Sketch

This structural frame requires pockets to minimize its weight.

You will control the thickness of the walls and the webs by addingappropriate sketch constraints.

Drag and Alternate Solution will be useful tools as you work on thesketch.

Step 1: Open frame_1.

Step 2: Constrain the sketch using both dimensions and constraints toposition the sketch curves relative to the solid edges and datumplanes.


Set the Rendering Style to Wireframe with Dim Edges.


Choose Fit.

Choose Constraints.


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Select the three sketch arcs (1) and the solid edge (2) shownbelow and apply a Concentric constraint.

Select the three sketch arcs and Apply an Equal Radiusconstraint.

Choose Inferred Dimensions.


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Add a Radius constraint with a value of 2.25 to the arc (1)shown below.


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When you use a dynamic input window end each valueentry with the enter key.

For example, in the next step, use enter to complete thedimension value 0.2, and then activate the name field andselect all of the existing text.

Next, type the name wall and again use enter to completethe edit.

Create the wall dimension as shown below. Remember to namethe expression wall.

If the sketch line is lying off the solid face instead of overthe face, use Alternate Solution to flip the wall dimension.

Choose Constraints.

When you apply constraints between datum featuresand sketch curves the constraints have to be appliedindividually.

In the next example, select one line and one datum planeand apply a parallel constraint. Repeat for the rest of thelines.


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Apply Parallel constraints to the objects as shown below.

You may avoid needing to use Alternate Solution later:drag these curves to their proper relationships afterapplying geometric constraints and before dimensioning.

Apply the dimensions as shown below.


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When you key in the first letter of wall you will havethe option of choosing from a list of all functions andexpressions. Since no function names or other variablesstart with “w” there will be only the one list entry to select.

Click on your selection in the list, or use the arrow keysand enter to make a selection.

When the value appears in the dynamic input window,use enter twice: one time to place the value in the inputwindow and again to record the value and update thesketch.

Apply the remaining dimensions as shown below.

The sketch is now fully constrained and positioned on the solidbody.


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Step 3: Extrude the sketch and subtract it from the solid to create thepockets. Use a Start distance of 0 and an End distance of 0.56.

Step 4: Edit the chamfer feature.

Choose Edit→Feature→Edit Parameters.

Select the Chamfer feature and choose OK.

Change the First Offset value to 1.5.

Tab to the Second Offset and change it to 2.0.

Choose OK twice.

Examine the part to ensure the update was correctly applied.Look to see if any Alternate Solutions need to be applied to thedimensions from the datum planes.

Step 5: Optional: Add blends to the solid edges.


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For the first set of the first blend, specify 0.125 on the verticaledges of the pockets.

For the second set of the first blend, specify 0.325 on the outervertical edges of the solid.

For the second blend, using selection intent Tangent Curves,specify 0.0625 on the floors of the pockets.



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Activity - Using Positioning Dimensions

The design requirements for this part will eventually require thesketch to be used as a user defined feature or UDF. When you use asketch in a UDF, it is convenient to use positioning as an intuitivetool for placing and aligning the feature.

First you will fully constrain the sketch using constraints. Nextyou will replace constraints that are specific to this solid body withflexible positioning dimensions.

Step 1: Open position_1.

Step 2: Choose Start→Modeling.

Step 3: Use dimensional constraints to locate the sketch on the placementplane.


Choose Fit.

Choose Show All Constraints.

Notice that there are two vertical, one horizontal and twotangent constraints.


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Choose Inferred Dimensions.

Select the arc center and the bottom horizontal edge of thesolid body.

Place a vertical dimension to the right of the part.


Notice that the status line indicates that 1 constraint is needed.Also notice that the vertical DOFs no longer appear.


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Select the arc center again and the right vertical edge of thesolid body.

Place a horizontal dimension above the part.


The sketch is now fully constrained


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Step 4: Test the sketch to see if more flexible positioning can be addedwith the current constraints.

In some instances the sketch needs to be rotated 20degrees as shown below.

Choose the Angular dimension type.


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Select the objects in the order and at the locations as shownbelow.

Place the dimension to the right of the part.

Notice how the dimension and horizontal constraint are displayedin the over constrained color.

Also notice that the status line indicates that the sketch is overconstrained.

The angular dimension and horizontal constraint are presentlyredundant (over constrained).

If you were to change the angular dimension value, the dimensionwould then be in conflict with the horizontal and both verticalconstraints.

Choose Undo.


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Step 5: Prepare to create positioning dimensions.

Add Positioning Dimensions on the Sketchertoolbar. (Actually, there is a stack of three icons.)Alternatively you could use Tools→PositioningDimensions.

Choose Create Positioning Dimensions.

An error window pops-up informing you that you cannot applypositioning dimensions when there are sketch constraints toexternal objects. This message is referring to the dimensions goingto the solid body.

Choose OK.

You will now remove the dimensional constraints to thesolid body and replace them with Positioning Dimensions.

In a future UDF, users who create instances of your sketchwould apply similar positioning dimensions to meet theirdesign intent.

Select the two dimensions that position the sketch to the solidbody.

Choose Delete.

Choose Constraints.


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Choose the endpoint (1) shown below and apply a Fixed

constraint.

Notice that the sketch curves change to the fully constrained color,and all degree of freedom indicators are removed.

The sketch is now fully constrained with no external references.

When you use positioning it will apply to the entire sketch.

Step 6: Use a Positioning Dimension to define the distance from the arccenter to the lower edge of the solid body.

Choose Create Positioning Dimensions.


Select the bottom horizontal edge of the solid body.

Select the arc and choose Arc Center.

Choose OK to accept the value of 3.


3


Step 7: Create a Positioning Dimension to define the distance from the arccenter to the right hand edge of the solid body.


Select the right vertical edge of the solid body.

Select the arc and choose Arc Center.

Choose OK to accept the value of 2.

Step 8: Create a Positioning Dimension to define the angle of the sketchwith respect to the lower edge of the solid body.

Choose Angular.

Select the objects in the order and at the locations as shownbelow.


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Key in 20 and choose OK.

Notice how the sketch rotated even though there are verticaland horizontal constraints present. This is because positioningdimensions operate on the entire sketch as a feature.

Choose Orient View to Sketch.

Choose Fit.

Now you can see that the sketch was rotated and that the verticaland horizontal constraints are still valid relative to the sketchplane.

Step 9: Edit the angle positioning dimension.


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Choose Edit Positioning Dimensions from the pull-down.

In the graphic window, select the angle positioning dimension.

Key in a value of 45 and choose OK twice.

Choose Orient View to Sketch.

Fit the view.




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ReattachYou can reattach a sketch to a different planar face or datum plane than theone on which it was created. You can only reattach to a plane or face withan earlier time stamp.

The Reattach option also displays any for the sketch, and lets you redefinethe geometry referenced by them.

After you choose the Reattach icon, the reattach input boxes display.

Sketch in place

These options are from left to right:

• Sketch type – Lets you change between Sketch in place and Sketch onpath.

• Sketch Plane – Lets you choose a new sketch plane or planar face.

• OK – Lets you execute the reattachment.

• Cancel – Quits the reattachment operation.

To reattach a Sketch in place:

1. Select a new datum plane or planar surface (optional).

2. Select a horizontal or vertical reference (optional).

3. Choose OK.


3


Sketch on path

These options are from left to right:

• Sketch type – Lets you change between Sketch in place and Sketch onpath.

• Path – Lets you choose a new path or edit the existing one.

• Positioning Method – Lets you change the positioning method.

• Alternate Solution – This will be available when there are multiplepositioning possibilities.

• OK – Lets you execute the reattachment.

• Cancel – Quits the reattachment operation.

To reattach a Sketch on path:

1. Select a new path or modify the existing path (optional).

2. Modify the sketch plane orientation: Normal to Path, Normal to Vector,Parallel to Vector, or Through Axis (optional).

3. Modify the placement of the sketch by dragging or choose among:ArcLength, % ArcLength, or Through Point (optional).

4. Choose OK.

To redefine a positioning dimension:

1. Select a displayed positioning dimension to redefine. The original dialogused to define the positioning dimension displays.

2. Follow the prompts to choose new reference objects for the positioningdimension.

For information on positioning methods see the Modeling Online Help.


3


Reordering SketchesIn order to attach a sketch to a face or datum or define a horizontal reference,the geometry must come before the sketch in Timestamp order. Reorderingaccomplishes this.

Reordering is also necessary when you attempt to add generating or guidecurves of a swept feature that occurs before the sketch. The sketch mustbe reordered before (earlier than) the swept feature that is generated orguided by the curves. Once the timing of the sketch relative to the sweptfeature is resolved, and the curves are added to the sketch, the curves may beconstrained just as any other sketch curve.

Sketches appear in the Part Navigator and the list of features presentedwhen performing an Reorder. A sketch can be located anywhere after itsreference geometry in the creation order.


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Activity - Reattaching a SketchStep 1: Open reattach_1.

In this activity you will reattach a sketch that defines twocam blocks (1). The design has changed so that the blocksmust be mounted on the opposite face, as shown below.

Step 2: Investigate the current placement face and horizontal referenceof the sketch.


Change the Rendering Style to Wireframe with Dim Edges.

Make the sketch layer 22 and datum layer 62 selectable.

Use the push pin icon to lock the Part Navigator in the

open position.

Make sure the Part Navigator is in the Design View; i.e.,Timestamp Order does not have a check beside it.


3


Expand the nodes Solid Body, Unite (13), Solid Body, Extruded(11), Direction, and Sketch (9) until the Horizontal Referenceand Placement Face of Sketch (9) “INSERT_RELIEF” aredisplayed, as shown below.

One at a time, select Datum_Plane(2) and the Face nodeunder Placement face, noting which entities highlight in thegraphics window.


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Double-click the sketch icon beside Sketch (9)“INSERT_RELIEF” to activate the sketch.

Unpin the Part Navigator to expand the graphics viewing area.

Step 3: Reattach the sketch.

Display Orient View to Model on the Sketcher toolbar, oruse the View menu.

Choose Orient View to Model.

Choose Reattach.

Select the face shown below.

Click on the Y axis of the coordinate system.

Select the datum plane to define the vertical direction.

Choose OK.



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Shade the model and review the part.

The sketch is now reattached to the defined face and the cam blockfeatures are rebuilt.



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Activity - Moving SketchesThe part for this activity contains two dimensional geometry for a switchbase. The data may have originated from another system.

You will selectively eliminate some of the geometry and constrainthe remainder in sketches so that parametric control over the modelmay be defined by the geometry.

You will initially create the sketches on the same plane. Later youwill move two of the sketches into the proper orthogonal planes andextrude them to define a solid model.

Step 1: Open switchbase_1.

Step 2: Move the curves required for each profile sketch to separate layers.


Choose Format→Move to Layer.


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Select only the two circles in the "top" view and choose OK.

Key in 21 and choose Apply.

Choose Select New Objects and move the lines shown below inthe "front" view to layer 22.

Move the curves shown below in the "right" view to layer 23.

Step 3: Create expressions for the diameter and height.


Create expressions:

Name Formula Dimensionality Unitsdia 3.75 Length Inchesh 5.75 Length Inches


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Step 4: Create a sketch for the top profile.

Change the work layer to layer 21 and make all other layersinvisible.

Create a sketch named S21_TOP on the XC-YC plane.

Choose Fit.

Add the two circles to the sketch.

Step 5: Constrain the sketch for the top profile.

Add constraints to position the sketch so that both circlecenters are aligned with the two datum axes.

Add a dimension for the outer diameter. Change the value ofthis expression to dia to associate it to the expression.

Choose Finish.

Choose Fit.

Step 6: Move the datum plane and two datum axes to layer 61.

They are no longer required for this sketch but will be referencedby the other sketches.


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Step 7: Create an extruded feature using the top profile.

Change the work layer to layer 1 and keep layer 21 selectable.

Change to a Trimetric view orientation. (HOME key.)

Extrude the sketch S21_TOP in the default (+ZC) directionusing an End distance of h and a Start distance of 0.

Step 8: Create a sketch for the front profile.

Change the work layer to layer 22. Make layer 61 selectableand all other layers invisible.

Choose Fit.

Create a sketch named S22_FRONT. Select the existing datumplane as the sketch plane and select the datum axis parallel tothe XC axis as the horizontal sketch axis.

Choose Fit.

Add all of the curves on layer 22 to the sketch.

Step 9: Constrain the front profile sketch.

In Sketch→Preferences make sure Dynamic ConstraintDisplay is inactive (off) so you can see all of the constraints.

Use the Automatic Constraints to create horizontal andvertical constraints.


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Add dimensions for the total height and width as shown below.

The numeric suffixes you see may differ from theillustration.

Test the behavior of the sketch by changing the heightconstraint to 7.0 and the width to 5.0.

Notice that the sketch does not satisfy the design intent andremain symmetrical when the expressions are changed. To satisfythe design intent you can add a reference line and additionalconstraints.

Choose Undo (twice if necessary) to change thedimensions back to their original values.


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Create a vertical line between the midpoints of the twohorizontal lines shown below and convert it to reference. Afteryou create the line verify the inferred constraints and Undo totry again if necessary.

You may need to enable Mid Point in the Snap Pointtoolbar so that the system can infer the correct constraints.

Remember that you can add multiple constraints toselected curves if you hold the Control (Ctrl) key as youselect the curves.

Add the new dimension as shown below and make the twopairs of lines (1) and (2) both Collinear and Equal Length.

Change the value of the expression for the total width to diaand the total height to h.

Choose Finish.


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Step 10: Create associative reference features to be used as attachmentfaces for the front and right profile sketches, and as location aids.

Change the work layer to layer 62. Make sure layers 1 and 61are selectable to display the solid and the other datum objects.

Choose Datum Plane and create a datum plane throughthe axis of the outer cylindrical face of the solid.

Create another datum plane through the axis of the cylindricalface and at a 90 degree angle to the plane you just created.

Choose Datum Axis and create a datum axis through theaxis of the cylindrical face of the model pointing in the ZC+direction.

The front profile sketch will be attached to the datum plane thatis parallel to the ZC-XC plane. However, the plane was createdafter the sketch and cannot be referenced as a target face unless itprecedes the sketch.


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Step 11: Reorder the sketch after the datum planes.

Choose the Part Navigator icon.

In the Part Navigator, place the cursor on theS22_FRONT:SKETCH node. The sketch will appear underUnused Items in the Design View.

Press the right mouse button to display the pop-up menu, slidethe cursor down to the Reorder After option, and select the lastdatum axis from the cascading menu.


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Step 12: Attach the front profile sketch to a datum plane.

Make layer 22 selectable to display the sketch.


Enable Orient View to Model on the Sketcher toolbar.


Choose Reattach.

Select the datum plane that lies in the ZC-XC plane as thesketch plane.

Notice the Datum Axis used for the horizontal sketch axis is stillvalid. It is not necessary to redefine all steps during the reattachoperation.

Choose OK.


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Step 13: Position the sketch.

Choose Fit.

Add a constraint to make the centerline of the sketch Collinearwith the datum axis through the cylindrical face axis (1).

Add another constraint to make the lower horizontal line inthe sketch Collinear with the datum axis that is parallel tothe XC-axis (2).



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Step 14: Extrude the front profile sketch.

Extrude the sketch S22_FRONT along the default direction(YC axis) using Start and End values Through All and choosethe Boolean option Intersect.


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Step 15: Create the sketch for the right profile.

Change the work layer to layer 23, make layer 61 selectable,and all other layers invisible.

Create a sketch named S23_RIGHT. Once again, define thesketch plane with the datum plane defined for the S21_TOPsketch and select the datum axis parallel to the XC axis as thehorizontal sketch axis.

Choose Fit.

Add all the curves to the sketch.

Step 16: Constrain the right profile sketch.

Choose Automatic Constraints.

Set the Distance value to .01.

Toggle on: Horizontal, Vertical, Coincident, Parallel, Tangent,and Equal Length.

Choose OK.


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Create two vertical reference lines between the midpoints ofthe horizontal lines as shown below.

Add the dimensions as shown above.

The numeric suffixes you see may differ from theillustration.


3


Change the value of the expression for the width to "dia" (1)and the value of the expression for the height to "h" (2) toassociate them to the other sketches.


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Step 17: Attach the right profile sketch to the other new datum plane.

Make layers 1 and 62 selectable.


Choose Fit.

Choose Reattach.

Select the datum plane that lies parallel to the four flat facesof the model.

Choose OK.


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Step 18: Add constraints to position the sketch.


Choose Fit.

Add a constraint to make the centerline of the sketch collinearwith the datum axis through the cylindrical face axis (1).

Add another constraint to make the lower horizontal line inthe sketch collinear with the datum axis that is parallel to theXC axis (2).



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Step 19: Extrude the right profile sketch.

Change the work layer to layer 1.

Choose Fit.

Extrude the sketch S23_RIGHT along the default direction(XC axis) using a Start and End distances of Through All andchoose the Intersect Boolean option.

Make all layers invisible.

Note that the work layer is never affected when youselect the layer category All and then choose Invisible.

Step 20: Edit the expressions to modify the part.


If necessary choose More Options.

Set Listed Expressions to User Defined.

Change the value of the expression dia to 4.25 and the valueof the h to 6.5.

Choose OK to update the model.



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Mirroring in a SketchThe sketch mirror functionality provides a means for copying geometry andconstraints within the context of a sketch whenever the sketch design intentis meant to be symmetrical. The mirror function may provide a time savingoption.

To mirror sketch curves:

• Choose Mirror.

• Select the mirror centerline.

• Select the curves to be mirrored.

• Choose OK or Apply.

The mirror centerline you select will be automatically converted toreference status if it is not already a reference line.

A Mirror constraint is created between each new curve createdthrough the Mirroring process and the original curve.


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Activity - Mirroring Sketch Objects

Step 1: Open mirror_1 and if necessary choose Start→Modeling.

This part file contains a sketch and an extruded solid bodythat represent half of a V-Block. You will mirror the sketchand update the model.


Double click on a sketch curve.

The status line indicates that the sketch is fully constrained.

Step 3: Mirror the sketch curves.

Choose Mirror.


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Select the vertical line (1) as the mirror centerline.

Click MB2 to advance the selection step to Mirror Geometry.

Press the key combination Ctrl+A to select the remainingsketch geometry.

Choose OK.

Step 4: Edit the angle of the V-block.

Double-click on the p2=60.000 dimension.

In the dynamic input box key in 50 and press Enter.


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Notice that both sides of the sketch updated.


In the part navigator (Design View) verify that there is still onlyone solid body.

After the mirror centerline was converted to reference status theremaining curves and their mirror images created a single closedloop.



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SummarySketches can be reconfigured by using an alternate solution when more thanone configuration applies to a given set of constraints.

Sketches also can be dragged to other locations or in relation to their ownmembers. Managing sketches will allow you more flexibility when you createyour designs.

Positioning sketches using dimensions or constraints or a combination of bothcan help you maintain design intent when related features change.

Reattaching a sketch to another sketch plane offers you greater flexibilityin your final configuration.

In this lesson you:

• Applied Alternate Solutions to obtain the appropriate profile.

• Located sketches using constraints.

• Located sketches using positioning dimensions.

• Reattached sketches.

• Reordered sketches.

• Mirrored sketches.


4

Lesson

4 Sketch on Path Overview

Purpose

This lesson provides an introduction to the Sketch on Path option availablewithin the Variational Sweep operator.

For more detailed information, use the following NX helpdocumentation Design→ Modeling→Creating Objects From the InsertMenu→Sweep→Variational Sweep.

Objectives


• Understand When this Option is Available

• Understand the Sketch on Path Geometry Elements

Sketch on PathSketch on Path provides a single definition process that allows you to create adatum plane perpendicular to a string of curves or edges and a sketch withorigin and orientation related to both the path and the datum.

• Sketch on Path makes it easy to create input for the Variational Sweepor V-Sweep command

• Sketch on Path captures the master section

• Guide curves such as curves or edges can be captured by the sketch usingIntersect

• Choose from several orientation functions to control the sketch planerelative to the path:

– Normal to Path

– Normal to Vector


4

Sketch on Path Overview

– Parallel to Vector

– Through Axis

• The datum axes are automatically calculated by face properties adjacentto the path

• Easily move the sketch plane along the path using the Reattach function

• Reattach a template Sketch in place to make it into a Sketch on path

• The location of the sketch on its path is defined by a pair of expressions,one for arclength and one for the percentage.

• If used in dimensions of the sketch on path, these arclength andpercentage expressions will update the sketch dimensions according tothe current position of the sketch

– The arclength and percentage expressions can be used to define designintent in a v-sweep

– V-sweep generates the full range of values of the arclength andpercentage expressions corresponding to all positions of the sectionalong the path

– The percentage expression divided by 100 is a fraction between 0 and1; thus pn/100 (where pn is the name of the percentage expression)can be used identically to the controlling parameter in law curves


4

Sketch on Path Overview

SummaryThe Sketch on Path option provides you with the ability to create associativeGuide Curves and Section Strings within the Variational Sweep operator.When the feature is completed editing is assessable through familiar NXSketch tools such as expressions, reattach and relative datum features.

In this lesson you:


5

Lesson

5 Additional Sketching Techniques

Purpose

This lesson describes additional techniques that may be used to manipulatesketches.

Objectives


• Edit a Defining String

• Suppress and Delete Sketches

• Animate Sketch Dimensions


5

Additional Sketching Techniques

Edit Defining String

Overview

Sketches may be used to define profiles for extruded, revolved, or sweptfeatures and paths for swept features. Profiles are called Section Strings andthe paths are called Guide Strings.

Sketch objects that define another feature of the solid model cannot simply bedeleted due to the parent/child dependency relationship.

Edit Defining String is accessed by displaying the icon in the SketchOperations toolbar or via Edit→Edit Defining String in the sketchenvironment.

This option allows objects to be added to or removed from a string of objectsdefining a Section String or Guide String that has been used to create a solidfeature.

When the Edit String dialog displays, the system shows a list of featuresassociated with the active sketch. By default, the top feature in the list ishighlighted in the dialog and the sketch objects associated with the featureare highlighted in the graphics area.

To add objects to the defining string, simply select them.

To remove objects from the defining string, hold down the Shift key whileselecting them.


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An option menu is provided to allow filtering of selectable objects. Optionsare provided for All (the default), Curve, Edge, Face, and Sketch.

The radio buttons at the top of the dialog, Section and Guide, are for instanceswhere sketches are used both as a section string for one feature and as aguide string for another feature. In these cases the system provides forediting of defining strings of the non-active sketch because of the associativityof the sweep along guide feature.


5


Deleting or Suppressing Sketches

Overview

Since sketches are features of the model, they may be deleted or suppressedby choosing Edit→Delete or Edit→Feature→Suppress.

Sketches may also be deleted or suppressed from the Part Navigator.


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Activity - Edit Defining StringIn this activity you will modify the profile of a part that already exists bychanging the curves that define the profile.

Step 1: Open bbqcover_1.

Step 2: Activate the sketch defining the profile.


Choose Edit→Sketch.

Since S21_CROSSSECTION is the only sketch available, it isautomatically opened for editing.

Step 3: Change the profile defining the part.

Make layer 1 Invisible.

Choose Studio Spline on the Sketch Curve toolbar.

Use the Through Points method.

Verify that the degree is 3.

Make sure that End Point is active on the snap point toolbar.


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Start with the upper left endpoint on the sketch as shown.Follow with points 2, 3, and 4 as cursor locations. Finish withthe upper right endpoint as shown.

1

23

4

5

Choose OK to signal the end of point specification.

Choose Constraints.

Select the left angled line and the left endpoint of the splineas shown below. Make sure the spline is highlighted whenselecting the left endpoint.

Apply a Slope of Curve constraint to these objects.

Repeat the previous action for the right angled line and theright endpoint of the spline.


5


Step 4: Add six new dimensional constraints to the spline points as shownbelow.

Your numeric suffixes may differ. Be careful to preservethe relationships illustrated.

Step 5: Edit the defining string for the model.

Display the Edit Defining String icon in the SketchOperations toolbar.

Choose the Edit Defining String icon.


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In the dialog the Section string for EXTRUDED(4) is the onlychoice available.

With the Edit String dialog still displayed, select the splineto add it to the string.

Hold down the Shift key and select the top horizontal sketchline to remove it from the string.

Choose OK.


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Step 6: Convert the extraneous line to a reference line.

This line is still needed because the spline is dimensioned to it.

Hold down MB3 over the line until the radial pop up optionsappear.

Slide down and to the right to chooseConvert To/From

Reference.


Examine the new and improved barbecue cover.



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Activity - Suppressing and Deleting SketchesIn this activity you will suppress and delete a sketch and observe the effectson features that depend on it.

Step 1: Open delete_1.

Step 2: Suppress a sketch.


Choose Edit→Feature→Suppress.

Choose the sketch named S21_CAM from the Feature Selectiondialog.

The dependents of the sketch are also selected. This includesall of the features except the datum plane and axes used todefine the sketch plane.

Choose OK, and observe the effect on the model.

Step 3: Unsuppress the sketch.

Choose Edit→Feature→Unsuppress.

Choose all of the suppressed features from the FeatureSelection dialog (Choose the top feature in the list and dragwith MB1 to the bottom of the list).

Choose OK and again observe as the model updates.

Step 4: Delete a sketch.

Pin the Part Navigator in the open position.


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Make sure that you are in the Design View, with TimestampOrder inactive.

Expand the Dependencies window.

Expand the node for the bottom feature in the hierarchy,Extruded(4).

Note that the arcs and lines that make up the extruded section areall named, and all nodes can be further expanded.

Make sure the Extruded(4) node is selected, so that Detailsare visible.

If necessary, expand the Details window

In the Dependencies window, note that both the Children andParents nodes can be expanded.


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If necessary, expand the Parents node in the Dependencieswindow.

Examine the parent-child relationships of the feature.

Expand any one of the nodes for lines or arcs under Extruded(4).

Note that Sketch(3) “S21_CAM” is the parent of the root featureof the solid body, Extruded(4). Note that the only parents of thesketch are the datums used to position it.

Place the cursor over either of the Sketch(3) nodes, then clickMB3 and choose Delete.

A Notification window pops up informing you that deleting thisfeature will affect other features.

Choose Information

The Information window lists the other features that will also bedeleted, every feature except the datums.

Close the Information window

Choose OK in the Notification window.

Note that all dependents of the sketch are also deleted.

There is nothing under the Model Node.

The datums now appear under the Unused Items node.


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Step 6: Examine the customer defaults that affect the behavior of thesystem as you delete features.

Choose File→Utilities→Customer Defaults.

Choose Modeling→General, and click the Delete and Suppresstab.

On the Delete and Suppress page hover the cursor overthe question mark icon for each option to examine a brief

explanation of what the option does.

Cancel the dialog without saving any changes.


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AnimateThe Animate function dynamically displays the effect of varying a givendimension over a specified range. Any geometry affected by the selecteddimension is also animated. The behavior of the animation is relative to theexisting dimensions and constraints.

Access Animate by displaying the Animate Dimension icon in the SketchConstraints toolbar, or via Tools→Constraints in the sketch environment.

Dimensions list box: Lists the dimensions that can be animated.

Value: The value of the currently selected dimension.

Lower Limit: The smallest value that the dimension will be during theanimation. The default limit is the selected dimension value minus 10%.

Upper Limit: The largest value that the dimension will be during theanimation. The default limit is the selected dimension value plus 10%.

Steps/Cycle: The number of times that the dimension value changes when itmoves from the upper limit to the lower limit (or vice versa).

Display Dimensions: Optional: lets you display the original sketchdimensions during the animation.


5


Activity - Animating Sketch DimensionsStep 1: Open animate_1.

Step 2: Animate the first sketch.



Toggle Show All Constraints to enabled.

The constraints that presently exist in this sketch are:

Lines are either horizontal or vertical.

Lines are equal length to each other.

Arcs are equal radius to each other.

Lines and adjacent arcs are tangent.

Display Animate Dimension in the Sketch Constraintstoolbar.

Choose Animate Dimension.

Pan the sketch so that none of the geometry is hidden behindthe dialog.


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Select the p5=1 dimension.

Type the following values:

• Lower Limit = 0.25• Upper Limit = 2.75• Steps/Cycle = 20

Choose Apply.

The sketch animates the radius dimension within the animatelimits and the present constraints of the sketch.

Choose Stop.

Change the Steps/Cycle value to 40 and choose OK.

Changing the number of steps per cycle slows down theanimation.

Remember to start relatively fast (low step count) andincrease step count only within the ability of your computerto meet your needs.

Choose Stop

Choose Finish.

Step 3: Animate the second Sketch.

Change the work layer to 22 and make layer 21 Invisible.


The constraints in the sketch consist of a fixed horizontal line and4 angular dimensions that are associative to each other.


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Select the p0=43.2 dimension.

Choose OK to use the default values.

If you are using a space ball, you may zoom and panduring the animation so that you can see the entire rangeof motion.

Choose Stop

Edit the p2 dimension formula to read p1*9 .

Use the sketch dimension dialog or the formula editor.


Select the p0=43.2 dimension.

Set the Steps/Cycle back to the default value, 20.

Choose OK to accept the remaining defaults.

The animation now dynamically reflects the new dimensionalvalue.

Choose Stop

Choose Finish.

Step 4: Animate the third Sketch. (Optional)

Change the work layer to 23 and make layer 22 Invisible.


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Review the sketch constraints. Notice the reference line withthe constant length constraint.


Select the p9=3 dimension.

Choose OK to accept the defaults.

Choose Stop when you are done viewing the animation.

Choose Finish.



5


SummaryThe Edit Defining String feature in NX provides the ability to add orremove objects from sketches to change the shape of the sketch. When thestrength analysis of your design indicates that you need another rib, you canaccommodate the change with a minimum of delay. Suppressing or deletingsketches can provide you a means to create varying configurations of yourfinal product.

In this lesson you:

• Edited the defining string of a swept feature.

• Deleted, suppressed, and unsuppressed sketches.

• Animated sketch dimensions.


Index

AAlignment Lines . . . . . . . . . . . . . . 1-22Animate Sketch Dimension . . . . . . 5-14

DDelay Evaluation . . . . . . . . . . . . . . 1-57Delete Sketch . . . . . . . . . . . . . . . . . 5-4DOF . . . . . . . . . . . . . . . . . . . . . . . 1-46

EEdit Defining String . . . . . . . . . . . . . 5-2Evaluate Sketch . . . . . . . . . . . . . . 1-57

IInfer Constraint Settings . . . . . . . . 1-21

QQuick Extend . . . . . . . . . . . . . . . . . 1-36Quick Trim . . . . . . . . . . . . . . . . . . 1-34

SShow/Remove Constraints . . . . . . . 1-66Sketch

Add Existing Curves . . . . . . . . . . 2-36Alternate Solution . . . . . . . . . . . . 3-2Automatic Constraint Creation . . 2-22Constraining . . . . . . . . . . . . . . . 1-48

Constraints . . . . . . . . . . . . . . . . 1-63Convert To/From Reference . . . . . 1-92Create Inferred Constraints . . . . . 2-5Creating . . . . . . . . . . . . . . . . 1-8, 1-13Curve Creation . . . . . . . . . . . . . . 1-21

Arc . . . . . . . . . . . . . . . . . . . 1-26Circle . . . . . . . . . . . . . . . . . . 1-27Fillets . . . . . . . . . . . . . . . . . 1-33Line . . . . . . . . . . . . . . . . . . . 1-24Profile . . . . . . . . . . . . . . . . . 1-23

Dimensions . . . . . . . . . . . . . . . . 1-48Editing . . . . . . . . . . . . . . . . 1-57Types . . . . . . . . . . . . . . . . . . 1-51

Drag . . . . . . . . . . . . . . . . . . . . . . . 2-2Mirror . . . . . . . . . . . . . . . . . . . . 3-62Naming . . . . . . . . . . . . . . . . . . . 1-11Overview . . . . . . . . . . . . . . . . . . . 1-2Positioning . . . . . . . . . . . . . . . . . 3-11Project . . . . . . . . . . . . . . . . . . . . 2-23Reference Direction . . . . . . . . . . 1-10Reordering . . . . . . . . . . . . . . . . . 3-40Show/Remove Constraints . . . . . 1-66Text Height . . . . . . . . . . . . . . . . 1-51

Sketch on Path . . . . . . . . . . . . . . . . 4-1Sketch Points . . . . . . . . . . . . . . . . . 1-46Snap Angle . . . . . . . . . . . . . . . . . . 1-22Suppress Sketch . . . . . . . . . . . . . . . 5-4

UUpdate Model . . . . . . . . . . . . . . . . 1-57

©UGS Corp., All Rights Reserved Sketcher Fundamentals – Student Guide Index-1

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L E A R N I N G

A D V A N T AG E

UGS Education Services offers a blend of training solutions for all of our product lifecycle management products. Our Online Store “Learning Advantage” was developed to provide our customers with “just in time” training for the latest in application developments. Here are some of the Learning Advantages:

• Customers have direct access • Self-paced course layout • Online Assessments • Just in time training for the latest release

To learn more about the “Learning Advantage” visit our website http://training.ugs.com or email us at training @ugs.com

STUDENT PROFILE

In order to stay in tune with our customers we ask for some background information. This information will be kept confidential and will not be shared with anyone outside of Education Services.

Please “Print”…

Your Name U.S. citizen Yes No Course Title/Dates NX4 SKETCHER / thru Hotel/motel you are staying at during your training Planned departure time on last day of class Employer Location Your title and job responsibilities / Industry: Auto Aero Consumer products Machining Tooling Medical Other Types of products/parts/data that you work with Reason for training Please verify/add to this list of training for Unigraphics, I-deas, Imageware, Teamcenter Mfg., Teamcenter Eng. (I-Man), Teamcenter Enterprise (Metaphase), or Dimensional Mgmt./Visualization. Medium means Instructor-lead (IL ), On-line (OL ), or Self-paced (SP) Software From Whom When Course Name Medium

Other CAD/CAM/CAE /PDM software you have used Please “check”! your ability/knowledge in the following…

Subject CAD modeling CAD assemblies CAD drafting CAM CAE PDM – data management PDM – system management

None � � � � � � �

Novice � � � � � � �

Intermediate � � � � � � �

Advanced � � � � � � �

Platform (operating system) Thank you for your participation and we hope your training experience will be an outstanding one.

Sketcher Course Agenda

Monday Morning • Introduction & Overview • Lesson 1. Sketching

Afternoon • Lesson 1. Sketching (continued) • Workbook Section 1 • Lesson 2. Constraining Sketches

Tuesday Morning • Workbook Section 2 • Lesson 3. Constraint Management • Workbook Section 3

Afternoon • Workbook Section 3 (continued) • Lesson 4. Sketch on Pat Overview • Lesson 5. Additional Sketching Techniques • Workbook Section 4

Accelerators

The following Accelerators can be listed from within an NX session by choosing Information→Custom Menubar→Accelerators.

Function Accelerator File→New... Ctrl+N File→Open... Ctrl+O File→Save Ctrl+S File→Save As... Ctrl+Shift+A File→Plot... Ctrl+P File→Execute→Grip... Ctrl+G File→Execute→Debug Grip... Ctrl+Shift+G File→Execute→NX Open... Ctrl+U Edit→Undo Ctrl+Z Edit→Cut Ctrl+X Edit→Copy Ctrl+C Edit-Paste Ctrl+V Edit→Delete... Ctrl+D or Delete Edit→Selection→Top Selection Priority - Feature F Edit→Selection→Top Selection Priority - Face G Edit→Selection→Top Selection Priority - Body B Edit→Selection→Top Selection Priority - Edge E Edit→Selection→Top Selection Priority - Component C Edit→Selection-Select All Ctrl+A Edit→Blank→Blank... Ctrl+B Edit→Blank→Reverse Blank All Ctrl+Shift+B Edit→Blank→Unblank Selected... Ctrl+Shift+K Edit→Blank→Unblank All of Part Ctrl+Shift+U Edit→Transform... Ctrl+T Edit→Object Display... Ctrl+J View→Operation→Zoom... Ctrl+Shift+Z View→Operation→Rotate... Ctrl+R View→Operation→Section... Ctrl+H View→Layout→New... Ctrl+Shift+N View→Layout→Open... Ctrl+Shift+O View→Layout→Fit All Views Ctrl+Shift+F View→Visualization→High Quality Image... Ctrl+Shift+H View→Information Window F4 View→Current Dialog F3 View→Reset Orientation Ctrl+F8 Insert→Sketch... S Insert→Design Feature→Extrude... X Insert→Design Feature→Revolve... R Insert→Trim→Trimmed Sheet... T

Insert→Sweep→Variational Sweep... V Format→Layer Settings... Ctrl+L Format→Visible in View... Ctrl+Shift+V Format→WCS→Display W Tools→Expression... Ctrl+E Tools→Journal→Play... Alt+F8 Tools→Journal→Edit Alt+F11 Tools→Macro→Start Record... Ctrl+Shift+R Tools→Macro→Playback... Ctrl+Shift+P Tools→Macro→Step... Ctrl+Shift+S Information→Object... Ctrl+I Analysis→Curve→Refresh Curvature Graphs Ctrl+Shift+C Preferences→Object... Ctrl+Shift+J Preferences→Selection... Ctrl+Shift+T Start→Modeling... M or Ctrl+M Start→All Applications→Shape Studio... Ctrl+Alt+S Start→Drafting... Ctrl+Shift+D Start→Manufacturing... Ctrl+Alt+M Start→NX Sheet Metal... Ctrl+Alt+N Start→Assemblies A Start→Gateway... Ctrl+W Help→On Context... F1 Refresh F5 Fit Ctrl+F Zoom F6 Rotate F7 Orient View-Trimetric Home Orient View-Isometric End Orient View-Top Ctrl+Alt+T Orient View-Front Ctrl+Alt+F Orient View-Right Ctrl+Alt+R Orient View-Left Ctrl+Alt+L Snap View F8

Evaluation – Delivery

NX 4 Sketcher, Course #TR10028 Dates thru

Please share your opinion in all of the following sections with a “check” in the appropriate box:

Instructor: ��

If there were 2 instructors, please evaluate the 2nd instructor with “X’s”

Instructor: �� 1. …clearly explained the course objectives 2. …was knowledgeable about the subject 3. …answered my questions appropriately 4. … encouraged questions in class 5. …was well spoken and a good communicator 6. …was well prepared to deliver the course 7. …made good use of the training time 8. …conducted themselves professionally 9. …used examples relevant to the course and audience 10. …provided enough time to complete the exercises 11. …used review and summary to emphasize important information 12. …did all they could to help the class meet the course objectives

Comments on overall impression of instructor(s):

Overall impression of instructor(s) Poor Excellent Suggestions for improvement of course delivery:

What you liked best about the course delivery:

Class Logistics:

1. The training facilities were comfortable, clean, and provided a good learning environment

2. The computer equipment was reliable 3. The software performed properly 4. The overhead projection unit was clear and working properly 5. The registration and confirmation process was efficient

Hotels: (We try to leverage this information to better accommodate our customers)

1. Name of the hotel Best hotel I’ve stayed at

2. Was this hotel recommended during your registration process? YES NO

3. Problem? (brief description)

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Evaluation - Courseware

NX 4 Sketcher, Course #TR10028 :

Please share your opinion for all of the following sections with a “check” in the appropriate box

Material:

1. The training material supported the course and lesson objectives 2. The training material contained all topics needed to complete the projects 3. The training material provided clear and descriptive directions 4. The training material was easy to read and understand 5. The course flowed in a logical and meaningful manner 6. How appropriate was the length of the course relative to the material? Too short Too long Just right

Comments on Course and Material:

Overall impression of course Poor Excellent

Student:

1. I met the prerequisites for the class (I had the skills I needed) 2. My objectives were consistent with the course objectives 3. I will be able to use the skills I have learned on my job 4. My expectations for this course were met 5. I am confident that with practice I will become proficient

Name (optional): Location/room

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Please “check” this box if you would like to receive more information on our other courses and services. (Your name is required at the bottom of this form)

Thank you for your business. We hope to continue to provide your training

and personal development for the future.

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unigraphics nx sketching fundamentals mt10028 (student guide)

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