This group of modifiers provides various tools for texture mapping: that is, managing UVW coordinates and mapping materials onto geometry.
The Unwrap UVW modifier lets you assign mapping (texture) coordinates to objects and sub-object selections, and to edit those coordinates by hand as well as with a variety of tools. You can also use it to unwrap and edit existing UVW coordinates on an object. You can adjust mapping to fit on Mesh, Patch, Polygon, HSDS, and NURBS models using any combination of manual and several different procedural methods.
By applying mapping coordinates to an object, the UVW Map modifier controls how mapped and procedural materials appear on the surface of an object. Mapping coordinates specify how bitmaps are projected onto an object. The UVW coordinate system is similar to the XYZ coordinate system. The U and V axes of a bitmap correspond to the X and Y axes. The W axis, which corresponds to the Z axis, is generally only used for procedural maps. A bitmap's coordinate system can be switched in the Material Editor to VW or WU, in which case the bitmap is rotated and projected so that it is perpendicular to the surface.
The UVW Mapping Add modifier is added to an object's modifier stack when you add a channel in the Channel Info utility. You can also add the modifier explicitly by choosing it from the Modifier List. It has no user interface.
The UVW Mapping Clear modifier is added to an object's modifier stack when you clear a channel with the Channel Info utility. You can also add the modifier explicitly by choosing it from the Modifier List.
The UVW Mapping Paste modifier is added to an object's modifier stack when you paste a channel in the Channel Info utility. It isn't available from the modifier list, and has no user interface.
Use the UVW XForm modifier to adjust tiling and offset in existing UVW coordinates. If you have an object with complex UVW coordinates already applied (such as a Loft object, or a parametric object with generated coordinates), you can apply this modifier to adjust those coordinates further.