Graphics Reference
In-Depth Information
Chapter 5
Subdivision Surface Modeling
Creation of 3D models goes well beyond the realm of simple primitive objects. Polygons, though a mainstay
of computer modeling and animation, are ineffective when re-creating realistic and organic forms. Using sub-
division surfaces (SubDs) enables you to create models without the blocky edges that detract from the image
and the realism of your scene. Proper use of SubDs opens the doors to a tremendous variety of models that
would be difficult or impossible to create with simple polygons.
This chapter covers the following:
• Using subdivision surface modeling
• Modeling organic objects
• Modeling semi-organic objects
• Modeling hard-surface objects
Using Subdivision Surface Modeling
In subdivision surface modeling, polygons cease to define the geometry. Instead, polygonal data is used to
direct the flow of smoothly contoured surfaces. To illustrate this easily, take the example of a simple cube.
Eight points define the surface of a cube. When connected by straight edges to create polygons, the primitive
shape takes form. With subdivision surfaces (or in this case PSubs) activated by pressing Shift+Tab, the cube
turns into a kind of lumpy sphere. The facets that we see in the surface of the sphere are caused by a low
subdivision level. By increasing the subdivision level to 3 or 4 (in the Mesh Properties panel), the lumpiness
disappears and the spherical shape becomes properly defined. This type of rounding and curved surface cre-
ation is typical of all subdivision surface models. The addition of extra edges, weighted points (or edges), and
shifts in polygonal flow (all of which are covered later in this chapter) add definition, sharpness, and detail to
the surfaces of an object.
Figure 5-1
shows an example of a subdivision surface model.
Figure 5-1:
Subdivision surface models can combine smooth curves with sharp creases to form complex
shapes.
