3ds Max® 2012 Bible

BONUS CHAPTER 4

Modeling with Patches

IN THIS CHAPTER

Creating patch grids

Editing patches

Working with patch subobjects

Apatch is a modeling type that uses curves to define the perimeter of the shape. Patches 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.

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, which permits greater control over the surface and makes it better for modeling things like clothes and natural objects like leaves.

Note

Patches have many similarities to the NURBS modeling type. NURBS stands for Non-Uniform Rational B-Spline. Coverage of NURBS is presented in Bonus Chapter 5 on the CD.

Another key advantage of Patch objects is that they efficiently represent the object geometry. If you examine some mesh objects, you'll notice that they contain a discrete vertex at the intersection of every edge and at the corner of every face. Patch grids, on the other hand, have a vertex only at the corner of every patch. Each patch can consist of several faces. This reduction ...