Maps are bitmaps or procedural textures that are used to give color and other apparent surface characteristics ("textures") to 3D objects in Max.
There can be different types of maps. Some maps wrap images about objects, while others define areas to be modified by comparing the intensity of the pixels in the map. An example of this is a bump map. A standard bump map would be a grayscale image. When mapped onto an object, lighter colored sections would be raised to a maximum of pure white and darker sections would be indented to a minimum of black. This enables you to easily create surface textures, such as an orange rind, without having to model them.
The basic parameters of a shader like diffuse, specular, self-illumination, opacity etc. can be mapped with a bitmap or a procedural texture. Clicking on the small button in front of the color swatch can do this job. Clicking on this button opens a Material/Map Browser. When a parameter is mapped, the small button shows “M”.
Figure 5-4: Shader Basic Parameters
Mapping the diffuse parameter with a bitmap will enable the bitmap to appear around the surface of the 3d object.
The Maps rollout is where you apply maps to the various materials. To use a map, click on the Map button; this opens the Material/Map Browser where you can select the map to be used. The Amount spinner sets the intensity of the map, and an option to enable or disable the map is available. For example, a white material with a red Diffuse map set at 50 % Intensity results in a pink material.
Figure 5-5: Maps Rollout
The available maps in the Maps rollout depend on the type of material and the Shader that you are using. Raytrace materials have many more available maps than the standard material. Some of the common mapping types found in the Maps rollout are discussed in this section.
The Material/Map Browser lets you choose a material or a map. When you click Get Material, the Browser that is displayed is modeless (you can leave it displayed while you do other work). However, when you display the Browser by clicking the Type button, a map assignment button in the Environment dialog, or from a projector light (see Advanced Effects Rollout), it appears as a modal dialog with OK and Cancel buttons.
The Material/Map Browser includes several browse options accessible as radio buttons on the left of the dialog box. The browse options include Material Library, MaterialEditor, Active Slot, Selected, Scene, and New. In order to choose a bitmap image as a map, you click on New, and the Bitmap on the top of the list appears.
Figure 5-6: Material/Map Browser
UVW Mapping Coordinates
An object assigned a 2D mapped material (or a material that contains 2D maps) must have mapping coordinates. These coordinates specify how the map is projected onto the material, and whether it is projected as a "decal," or whether it is tiled or mirrored. Mapping coordinates are also known as UV or UVW coordinates. These letters refer to coordinates in the object's own space, as opposed to the XYZ coordinates that describe the scene as a whole.
Mapping coordinates are used to define how a texture map is aligned to an object. These coordinates are expressed using U, V, and W dimensions, with U being a horizontal direction, V being a vertical direction, and W being depth.
UVW Map Modifier:
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.
UVW Map Modifier projects the UVW coordinates on the surface of the 3d object. This projection can be done in the following available ways.
- Shrink Wrap
- XYZ to UVW
Primitives, Loft Objects, and NURBS can generate their own mapping coordinates, but you need to use this modifier to apply mapping coordinates to mesh objects and patches.
Unwrap UVW Modifier
The Unwrap UVW modifier lets you control how a map is applied to a subobject selection. It can also be used to unwrap the existing mapping coordinates of an object. You can then edit these coordinates as needed. You can also use the Unwrap UVW modifier to apply multiple planar maps to an object. You accomplish this task by creating planar maps for various sides of an object and then editing the mapping coordinates in the Edit UVWs interface.
The Unwrap UVW modifier can be used as a self-contained UVW mapper and UVW coordinate editor, or in conjunction with the UVW Map modifier. If you use Unwrap UVW in conjunction with the UVW Map modifier, it is usually because you want to map the model with a method other than planar mapping, such as cylindrical or spherical mapping. You can animate UVW coordinates by turning on the Auto Key button and transforming the coordinates at different frames.