Displacement maps are grayscale textures you map to objects to create true surface relief (elevations and depressions) on an otherwise flat object.
With Displacement maps, depressions and elevations become part of the geometry of the object, changing the topology, unlike Bump maps that only create the illusion of surface relief.
- Because displacement changes the geometry of an object, displacement mapped objects usually require further tessellation (more triangles, which the renderer uses to approximate the smoothness of the surface). By default, Maya uses Feature-based displacement mapping to automatically add more triangles where required.
- File textures that are used for displacement mapping are usually connected via their outAlpha attribute. If the corresponding texture image file does not provide an alpha channel, then the displacement effect may be missing when using certain image formats. To avoid this, turn on the Alpha is Luminance attribute in the Color Balance section of the File Texture node. For more information, see File.
Displacement maps move an object’s vertices. By default, the height of the displacement is determined by the Alpha Gain value in the displacement map’s Attribute Editor. If you turn on Alpha is Luminance, the height result is based on the intensity of the pixels instead.
Use displacement maps to create shallow or deep surface relief. For example, you can create embossing, mountain peaks and valleys, spikes, and so on.
Because Displacement maps create true surface relief, they:
- can cast or receive shadows
- can be seen if you silhouette the object
- take more time to render than bump maps, which create the illusion of surface relief
You can connect a texture as a displacement map by connecting it to the Displacement mat attribute in the material’s shading group. See Connect a texture as a displacement map for more information.
Displacement Bounding Box
Because displacement mapping changes the volume of an object, it’s bounding box may become too small or too large.
Bounding boxes, which represent the bounding volume of an object, can be used to speed up Maya operations and can make a significant difference for complex models.