ABSTRACT
In the various branches of mathematics, science, and engineering which use curves and surfaces, there are many formulations which occur in every day use. Each has attributes which might be desirable for different parts of the modelling or analysis process; each has drawbacks. In this chapter we investigate some of the more well-known choices. Later chapters might involve blends in which some work is initially defined in one representation and then converted to another. The interrelationship possible among them affects the conversions possible.
