3ds Max 2012 Bible - Kelly L. Murdock [212]
Understanding Map Types
Within the Material/Map Browser is a wide variety of different map types. Understanding these maps and their parameters enables you to create lots of different materials.
Note
In previous versions of Max, the maps were divided into several different groups including 2D Maps, 3D Maps, Compositors, Color Mods, and Other, but now all maps are in the same group within the Material/Maps Browser. •
2D maps
A two-dimensional map can be wrapped onto the surface of an object or used as an environment map for a scene's background image. Because they have no depth, 2D maps appear only on the surface. The Bitmap map is perhaps the most common 2D map. It enables you to load any image, which can be wrapped around an object's surface in a number of different ways.
Many maps have several rollouts in common. These include Coordinates, Noise, and Time. In addition to these rollouts, each individual map type has its own parameters rollout.
The Coordinates rollout
Every map that is applied to an object needs to have mapping coordinates that define how the map lines up with the object. For example, with the soup can label example mentioned earlier, you probably would want to align the top edge of the label with the top edge of the can, but you could position the top edge of the map at the middle of the can. Mapping coordinates define where the map's upper-right corner is located on the object.
All map coordinates are based on a UVW coordinate system that equates to the familiar XYZ coordinate system, except that it is named uniquely so as not to be confused with transformation coordinates. For UVW coordinates, U represents the horizontal coordinate, V is the vertical coordinate, and W is along the surface normal. To keep them straight, remember that the UVW coordinate system applies to surfaces and that the XYZ coordinate system applies to spatial objects. These coordinates are required for every object to which a map is applied. In most cases, you can generate these coordinates automatically when you create an object by selecting the Generate Mapping Coordinates option in the object's Parameter rollout.
Note
Editable meshes don't have any default mapping coordinates, but you can generate mapping coordinates using the UVW Map modifier. •
In the Coordinates rollout for 2D Maps, shown in Figure 17.4, you can specify whether the map will be a texture map or an environment map. The Texture option applies the map to the surface of an object as a texture. This texture moves with the object as the object moves. The Environ option creates an environment map. Environment maps are locked to the world and not to an object. This causes the texture to change as the object is moved. Moving an object with an environment map applied to it scrolls the map across the surface of the object.
FIGURE 17.4
The Coordinates rollout lets you offset and tile a map.
Different mapping types are available for both the Texture and Environ options. Mapping types for the Texture option include Explicit Map Channel, Vertex Color Channel, Planar from Object XYZ, and Planar from World XYZ. The Explicit Map Channel option is the default. It applies the map using the designated Map Channel. The Vertex Color Channel uses specified vertex colors as its channel. The two planar mapping types place the map in a plane based on the Local or World coordinate systems.
The Environ option includes Spherical Environment, Cylindrical Environment, Shrink-Wrap Environment, and Screen mapping types. The Spherical Environment mapping type is applied as if the entire scene were contained within a giant sphere. The same applies for the Cylindrical Environment mapping type, except that the shape is a cylinder. The Shrink-Wrap Environment plasters the map directly on the scene as if it were covering it like a blanket. All four corners of the bitmap are pulled together to