from: http://en.wikipedia.org/wiki/Bump_mapping
Bump mapping is a technique in computer graphics to make a rendered surface look more realistic by simulating small displacements of the surface. However, unlike traditional displacement mapping, the surface geometry is not modified. Instead only the surface normal is modified as if the surface had been displaced. The modified surface normal is then used for lighting calculations as usual, typically using the Phong reflection model or similar, giving the appearance of detail instead of a smooth surface.

Here is a bump mapping tutorial for Photoshop.


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Andyba, 3d artist
skills: 3d modeling, texturing, rendering, 3d character animation, compositing
3d software experience: 3ds max, Maya, Softimage XSI, Deep Paint 3d, Body Paint 3D, Wings 3D, Z Brush
2d software experience: Adobe Photoshop, Adobe After effects, Macromedia Flash, Freehand