TABLE OF CONTENTS There are two VIZ objects that haven't been covered in the main body of this book, although they certainly play a major role in VIZ designs. Patches and NURBS surfaces are objects that allow you to form curved surfaces quickly by deforming their geometry. If you want to be able to sculpt a shape, you'll want to know about these objects. Patches and NURBS are often used in character animation and other design disciplines in which forming curved shapes are a major part of the design tool set.
A patch object is a collection of B zier patches that consist of vertices, edges, and surfaces similar to mesh objects. The main difference between mesh objects and patches is that the patch vertices can be controlled using B zier handles. These handles can be moved to apply a curve to the edges of the patch. The segments connecting patch vertices are splines that can be curved. Meshes always have straight-line segments connecting their vertices. In a sense, patches are like splines that have surfaces.
Perhaps the best way to understand patches is to see how one can be created and edited. Most of the standard primitives can be converted into editable patches. Let's take a look at how a plane standard primitive can be converted into an editable patch and then edited.
First, create a plane using the Standard Primitives option of the Geometry...
