Displacement map
From polycount
Displacement Map
A grayscale texture that stores height information, projected onto a highly-tesselated mesh in order to create displaced surface detail. Also called a Height Map.
Displacement maps are usually saved in a floating-point file format like 16- or 32-bit TIFF/TGA/EXR, because standard 8-bit grayscale images only have 256 levels of gray which often causes height information to be lost.
- Rendering ZBrush Displacement-Maps In External Renderers thread on ZBrushCentral
Displacement rendering methods in multiple applications. - See also Vector displacement map