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ES050 – Introductory Engineering Design and Innovation Studio

Features

Prof. Paul Kurowski

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Feature-Based Solid Modeling

Parts modeled by adding features to a base part Features “represent” manufacturing “operations”

holes, ribs, fillets, chamfers, slots, pockets, etc.

Material can be added or subtracted Features can be created by extrusion, sweeping,

revolving, etc.

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Feature-based Modeling Process Create base part Add features until final shape is achieved

Extruded Base Extruded Cut Extruded CutES1050 part 01.SLDPRT

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Examples

Extruded Base Extruded CutRib

ES050 part 03.SLDPRT

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Extruded Base Extruded Cut Extruded Cut

Fillet Extruded Boss

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Tools for Creating Features

Geometry is defined by sketching a 2D profile on a plane, and “extending” it into 3D

These profiles can be extended to 3D by: Extruding Revolving Sweeping Lofting

These operations can add material or cut it away

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Tools for Creating Features

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Extrusion

Sweep

Hole

Revolution

Loft

Extruded cut

Sample of features

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Extruded Part

Profile

Extrude

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Revolved Part

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Swept Part

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Lofted Part

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Other Features

Fillets, chamfers and rounds Shelling Holes Ribs

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Example

Rib Round

Fillet

HoleShell

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Alternative Modeling Approaches There are usually many ways to model an object A good approach requires few steps, and is easy

to modify if necessary The modeling steps do not necessarily

correspond to manufacturing steps Think the steps through before you

start!

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Modeling a Bracket

ES050 part 04.SLDPRT

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One Method

Step 1 Step 2 Step 3

ES050 part 04.SLDPRT

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Alternative method

Step 1 Step 2 Step 3

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Exercise Alternative sequence of modeling operations

Extruded Base Extruded CutRib

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ExerciseAlternative sequence of modeling operations

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ExerciseAlternative sequence of modeling operations

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ExerciseAlternative sequence of modeling operations

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ES050 – Introductory Engineering Design and Innovation Studio

Parameters and Sketching

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Outline

Design intent and parametric modelling Constraint types “Smart sketching” Examples

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Parametric modeling

Also know as Constraint-based User constrains geometry based on

Design Intent Design variations can be generated by

changing a few key dimensions Geometry is automatically regenerated

based on constraints

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Example

D1

D2=D1/2

D4=D3/2

D3=2*D1

•The part should be twice as long as it is wide•The hole should be centered in both directions•The hole diameter should be 50mm

D5=50

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Sketch parameters

(dimensions) constrained

by equations

Feature created with that

sketch + Cut extrude added

ES050 part 02.SLDPRT

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Smart Sketching

Most CAD systems use “smart” sketching tools Design intent is inferred, and constraints added

automatically as you draw For example, two lines that are nearly

perpendicular “snap” perpendicular, with a constraint

SolidWorks calls this “Automatic Relations”

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SolidWorks Automatic Relations (Geometric Constraints)

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Before adding constraints

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After adding geometric constraints

Tangent

Concentric

Perpendicular

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After adding dimensional constraints

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Constraint Types

Geometric constraints Dimensional constraints

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Boolean operations

Geometric constraints Dimensional constraints

boolean.SLDPRT

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Summary

Parametric modeling captures design intent

Easy to modify part geometry by changing parameters

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Home work