Chapter 27. Modeling with Patches and NURBS
Patches are a modeling type that exists somewhere between polygon meshes and NURBS. They are essentially polygon surfaces stretched along a closed spline. Modifying the spline alters the surface of the patch.
In many ways, patches have advantages over the more common mesh objects. They take less memory to store, are easier to edit at the edges, and are easy to join to one another.
NURBS is an acronym for Non-Uniform Rational B-Splines. They are the ideal modeling tool for creating organic characters because they are easy to work with, they give you good interactive control, they blend together seamlessly, and their surfaces remain smooth even when distorted. NURBS are superior to polygonal modeling methods when building models with smooth flowing contours such as plants, flowers, animals, and skin.
For real-time applications, neither of these methods is widely used.
In this chapter, you'll explore different methods of NURBS model construction and then look at some advanced NURBS tutorials.
Introducing Patch Grids
Because patches have splines along their edges, a patch can be deformed in ways that a normal polygon cannot. For example, a polygon always needs to be coplanar, meaning that if you look at it on edge, it appears as a line. A patch doesn't have this requirement and can actually bend, ...