Chapter 3. Sketch Techniques
This chapter will cover the principles of creating parametric sketches used in part or assembly modeling. All the skills in this chapter are based primarily on creating a single part, whether in a single-part file or in the context of an assembly file.
Autodesk Inventor utilizes two types of sketches, a 2D sketch and a 3D sketch. A 2D sketch is created on any geometry plane and is the more common of the two types. A 3D sketch is not limited to a sketch plane and can be comprised of geometry in any point in space. 3D sketches are often created from existing geometry. Both 2D and 3D sketches are controlled by two basic parameter types: dimensions and sketch constraints.
In Inventor, sketches are generally "roughed out" ...