Learning the Essentials of Part Modeling - Inventor 2013 and Inventor LT 2013 Essentials - page 70

When you're creating sketches for your own geometry, you won't create them
as loosely as this exercise. It is also important that you create your sketches to
be the approximate size of the finished shape. This will save you additional edit-
ing when you begin editing the dimensions. If you create a sketch proportional
to itself but accidentally make it the wrong size, it will automatically scale itself
based on the first parametric dimension you add to the sketch.

Editing Dimensions

This is the step where you will begin to see the value of parametrics. Creating
things to be the right size today doesn't mean you won't need to change that
size tomorrow. That is why approximating the geometry and adding precise
dimensions that change it is a great workflow.

Certification
Objective

1. Double-click the 30 dimension to edit its value.

2. When the Edit Dimension dialog box appears, change the value to 40,
and click the green check mark to make the change.

3. Edit the same dimension, and instead of entering a value, click the 60
dimension to link the two together.

4. Click the check mark to accept the new value.
Note that the value has been set to d0, and an fx now appears in
front of its value in the sketch. The d0 value refers to the name of the
dimension it is linked to, and fx denotes that this dimension is based
on another parameter.

5. Double-click the bottom dimension to edit it.

6. Enter the value of Width=100 , and accept it.
This changes the name of that dimension from d0 to Width and
updates the sketch to show the new size. You might have to zoom
out to see the sketch now.

7. Double-click the vertical dimension to see that it now refers to a
value of Width; it must remain associated to the other dimension
regardless of what changed.

8. Close the Edit Dimension dialog box without changing anything.

9. Select the vertical dimension again, and delete it.