The bump mapping technique is a very efficient technique as compared to displacement mapping. This technique is also used to add depth details or elevations to the surface of the geometry. However, this depth or elevation is fake. The geometry vertices do not undergo any change in the elevation. Instead, it uses the light illumination to simulate the depth appearance on a smooth surface. Light illumination uses the vertex normal information stored in normal maps to add depth. Like height maps, which store the height or elevation information, the normal map stores normal information. The idea in normal maps is to avoid calculation of normal maps for each triangular face; these can be sampled from the texture.

The designer responsible for designing mesh models first create a very high polygon (100,000+) mesh model, then they create a normal map out of it in an image file. Finally, they reduced the high-resolution model to a low polygon mesh (between 3000 and 5000 depends...