- 20.1. Overview
- 20.2. Key Concepts
- 20.3. Examples of NURBS Curves
- 20.4. NURBS Surfaces
- 20.5. Suggestions for Further Reading
- 20.6. NURBS Extensions

**Chapter Objectives. **After reading this chapter, you'll be able to do the following:

Create a variety of curves and surfaces

Trim areas of NURBS surfaces

Use NURBS profiles to specify the beveled edges of 3D text

*(Advanced)* Curves and curved surfaces provide a convenient mathematical means of describing a geometric model. Instead of using drawings, metal strips, or clay models, designers can use these mathematical expressions to represent the surfaces used on airplane wings, automobile bodies, machine parts, or other smooth curves and surfaces. Inventor uses a particular type of parametric polynomial, a NURBS (Non-Uniform Rational B-Spline), to represent curves and surfaces. This entire chapter can be considered advanced material.