Creating Contoured and Plastic Parts - Autodesk Inventor 2010: No Experience Required - page 388

The Transition Tab
Inventor automatically maps how a surface will transition between edges on the
various sections. You can override these selections on this tab and specify how a
surface is defi ned by selecting beginning and ending points for the surfaces of
the loft. With care, you can even introduce twist into the shape.
A lot of the options are selected for you automatically, and very often the auto-
matic result will give you the look and shape that you need.
Constructing the Fan Blade Shape
The loft is a sketched feature, so as usual that's where you'll begin. In this case,
rather than using origin planes or work planes that you create, I want to show
you a construction technique that I frequently use to fi gure out shapes. I have
used this for extremely complex shapes, but what you'll be doing would be even
more challenging without it:
1. Create a new part based on the Standard (in).ipt template.
2. Using a Construction linetype draw a circle with roughly a 4.5-inch
radius based on the sketch centerpoint.
3. Draw a rectangle with normal lines above the circle, as shown in
Figure 8.25.
4. Use a Vertical constraint to center the middle of the rectangle.
5. Add a Coincidence constraint between one of the bottom corners of
the rectangle and the top of the circle.
6. Add dimensions as shown in Figure 8.26.
7. Finish the sketch, and start the Extrude tool.