What Is a Parametric Equation?

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Overview

In Chapter 4, I introduced B-Splines, which can be treated as a superset of the Bezier curves shown in Chapter 3. In this chapter, I will talk about NURBS (Non-Uniform Rational B-Splines), which are a superset of B-Splines. NURBS are extremely powerful and they are an important feature in most modeling programs. It may seem paradoxical that this chapter is relatively short, but most of the important groundwork was set in the previous chapter. In this chapter, I'll expand the material with the following concepts:

• Rational versus nonrational splines

• The effect of weighted control points

• Conic sections with NURBS

• Finding the derivative of a NURBS curve

• Drawing NURBS