Bump mapping

In computer graphics, bump mapping is a technique where at each pixel, a perturbation to the surface normal of the object being rendered is looked up in a texture map and applied before the illumination calculation is done (see, for instance, phong shading.) The result is a richer more detailed surface representation that more closely resembles the details inherent in the natural world.

The sphere on the right is geometrically the same as that on the left, but has a bump map applied. This changes how it reacts to shading, giving it the appearance of a bumpy texture resembling that of an orange.

Original Publication:

Blinn, James F. "Simulation of Wrinkled Surfaces", Computer Graphics, Vol. 12 (3), pp. 286-292 SIGGRAPH-ACM (August 1978)