parametric constraints

PARAMETRIC CONSTRAINTSAssignment D5

CONSTRAINTS There are two types of constraints

Dimensional Constraints – You already know how to do Show Size & Location

Geometric Constraints – Show relationship between two objects HORIZONTAL, PARALLEL PERPENDICULAR TANGENT

Constraints can be applied manually or automatically

Using Constraints well, will make it easier to change dimensions

DO 1 Make a new

Standard(in).ipt Part

Start a new sketch on the XY plane

Create a triangle of arbitrary size like mine Make sure the bottom is horizontal

First Point

Second Point

Third Point

DO 2 Highlight everything (Ctrl-A)

The pick Show Constraints from the ribbon

CONSTRAINTS There are 12 types of geometric constraints

Coincident – Constraints two points together or one point to a curve

Collinear – Causes two lines or ellipse axes to lie along the same line

Concentric – Constraints two arcs, circles, or ellipses to the same center point

Fix – Constraints points or curves to a fixed location

CONSTRAINTS Parallel – Causes selected lines or ellipse axes to lie parallel to one

another

Perpendicular – Causes selected lines, curves or ellipse axes to lie at right angles to one another

Horizontal – Causes lines, ellipse axes or pairs of points to lie parallel to the X-Axis

Vertical - Causes lines, ellipse axes or pairs of points to lie parallel to the Y-Axis

CONSTRAINTS Tangent – Constraints a curve and line to be tangent to one another

Smooth – Create a curvature condition between a spline and a line, arc or spline.

Symmetric – Constraints two lines or curves to become symmetrically constrained about a selected line.

Equal – Selected arc/circles constrained to the same radius, or lines to the same length

DO 3 Notice at the

bottom of the screen inventor tells you that you need more dimensions to completely define the triangle

DO 4 Create the

bottom dimension as shown, your number will be different that mine, do not change the number to match mine

Notice the number at the very bottom of the screen was lowered

DO 5 Select the Vertical Constraint Icon

Pick the inclined line on the right and watch what happens

DO 6 If you hover your mouse over the

top orange box, you’ll see two Coincident constraints, this is what ties to the lines together to make a loop.

When you can’t make a loop, it’s because these constraints are missing or changed.

If you try to click the orange dot an move it, you’ll only be able to move it up and down, because it MUST be VERTICAL

DO 7 Add the lock

constraint to the bottom right corner

The angle dimension to the bottom left angle

You drawing should now say FULLY CONSTRAINED

OVER CONSTRAINING If you get this box,

that means that the dimension will be DRIVEN

It will have parentheses (0.03) and not be a regular dimension

DO 8 Move your mouse over the

orange block in the lower right corner of the shape

Delete the lock constraint by clicking on it and choose delete, do not clik the little X

Click and drag the top corner of the triangle, and see what happens.

Now click one of the corners and try and move the triangle, it should keep its shape because it’s constrained

AUTO DIMENSION Auto Dimension will help you

create a fully constrained sketch.

After you’ve put in the measurements you know, Auto Dimension will fill in any missing details, and help you see what Inventor is thinking.

Fully Constrained sketches are easier to work with too

DO 9 Draw a circle inside the triangle of

arbitrary size

DO 10 Click the Tangent constraint, then

the inclined line, and the circle

If you click the center point of the circle and try and move it, you’ll se it will change position and size, but it will stay tangent to the line.

Show me this on your screen

Save this as D5.triangle

Ask me for the 4 exercises D5.ex1-D5.ex4