The most common use for maps is to improve the appearance and realism of Materials. You can also use maps to create environments or projections from lights (see Advanced Effects Rollout ).
Maps can simulate textures, applied designs, reflections, refractions, and other effects. Used with materials, maps add details without adding complexity to the geometry of an object. (Displacement mapping can add complexity.)
You use the Material/Map Browser to load a map or create a map of a particular type. The Browser groups maps into categories according to their type. You can choose whether the Browser lists maps, materials, or both; you can choose which map types.
Different types of maps create different effects and behave in particular ways.
-
2D maps are two-dimensional images that are typically mapped onto the surface of geometric objects, or used as environment maps to create a background for the scene. The simplest 2D maps are bitmaps; other kinds of 2D maps are generated procedurally.
-
3D maps are patterns generated procedurally in three dimensions. For example, Marble has a grain that goes through the assigned geometry. If you cut away part of an object with Marble assigned as its texture, the interior matches the exterior.
-
Compositors are for compositing other colors or maps.
-
Color Modifiers alter the color of pixels in a material.
-
The "Other" category includes maps that create reflections and refractions. It also includes mental ray shaders and Camera Per-Pixel Projection maps.
When the mental ray renderer is active, the Material/Map Browser also lists mental ray shaders. Shaders are similar to maps, but use yellow icons. You assign them the way you do maps. The mental ray shaders don't fit into the map categories described in the previous section, and aren't described in this topic. See mental ray Shaders for links to shader descriptions.
Tip: When the default scanline renderer is active, you can view mental ray shaders in the Browser list, and assign them, by turning on Incompatible in the Show group. Incompatible shaders in the list are displayed in gray.
Maps have a spatial orientation. When you apply a material with maps in it to an object, the object must have mapping coordinates. These are specified in terms of UVW axes local to the object.
Most objects have a Generate Mapping Coordinates toggle. You can turn this on to provide default mapping coordinates. If the object has this toggle, it is also turned on automatically when you render the scene, or use Show Map In Viewport.
Some objects, such as editable meshes, don't have automatic mapping coordinates. For these types of objects, you can assign coordinates by applying a UVW Map modifier. If you assign a map that uses a mapping channel, but don't apply a UVW Map modifier to the object, the renderer displays a warning that lists objects that require mapping coordinates. You can also use UVW Map to change an object's default mapping.
See Mapping Coordinates.
Each object can have from 1 to 99 UVWmapping coordinate channels. The default mapping (from the Generate Mapping Coordinates toggle) is always UVW 1. The UVW Map modifier can send coordinates to any of these channels.
Each map in a material can use any UVW channel (if present), or other type of mapping that depends on whether the map is 2D or 3D.
You can set the mapping channel used by NURBS surface sub-objects in their creation or modification parameters.
You can position a 2D map on the surface of an object by using a map channel, any assigned vertex color, or the local or world coordinate systems. You can also choose different environment mappings. See Coordinates Rollout (2D).
You can position a 3D map within the volume of an object by using a map channel, any assigned vertex color, or the local or world coordinate systems. See Coordinates Rollout (3D).
Random noise values increase the complexity of maps and can give them a more natural look. For 2D maps, see Noise Rollout (2D). For 3D maps, you can assign a separate Noise map. See Noise Map.