Bump maps are grayscale textures you map to objects to create the illusion of surface relief (elevations and depressions) on an otherwise flat object.
With bump maps, depressions and elevations look real because they don’t alter the geometry of the surface the way Displacement maps do. Bump maps just change the direction of the surface’s normals based on the bump map’s Alpha Gain value.
Use bump maps to create very shallow reliefs. For example, you can make objects look like they are embossed, have shallow rolling hills, and so on.
Because bump maps are not true surface relief, they:
- cannot cast or receive shadows
- cannot be seen if you silhouette the mapped object
- take less time to render than displacement maps
Tip:
- Although scratches are like little depressions, you can more easily achieve them with 2D textures.