Computer Graphics

The sphere without bump mapping.


This sphere 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.

Bump mapping is a computer graphics 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 difference between displacement mapping and bump mapping is evident in this image; in bump mapping, the normal alone is perturbed, not the geometry itself. This leads to artifacts in the silhoutte of the object (the sphere still has a circular silhoutte).


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

See also[]

  • Fake bump mapping
  • Normal mapping
  • Parallax mapping
  • Displacement mapping

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