Animators and 3D visual effects (VFX) artists use bump mapping and other types of texture mapping to simulate realistic details on the surfaces of 3D-modeled objects and characters quickly and effectively. Bump maps are much more efficient than manually building every individual surface crevice, indentation, bump, wrinkle, or blemish into the 3D mesh.
In bump mapping, software projects a 2D grayscale image file onto the surface of a 3D object. This increases the illusion of reality by making 3D objects and characters appear to have bumps and indentations on their surfaces or skin. A bump map does not alter the shape of the 3D mesh. Rather, the degree of grayscale at each point determines the variation in the surface’s apparent depth, from black (down) to white (up).
Many texture mapping techniques within texture mapping software work in a similar way to bump mapping. For example, diffuse mapping applies basic textures, patterns, and colors to surfaces. Specular mapping uses 2D grayscale image maps to apply degrees of shininess/reflectivity to a surface.
Other texture mapping techniques accomplish essentially the same result as bump mapping but in different ways. For instance, normal mapping is like a newer and better version of bump mapping for complex and intricate surface textures. Instead of grayscale, normal maps use RGB data to vary the surface-normal depth information that tells the software how light should interact with the surface and to create the illusion of detailed textures through shading.
Neither normal maps nor bump maps alter the geometry of 3D models; instead, they create illusions. So, for example, their textures will not cast shadows. By contrast, displacement maps do physically displace the meshes they are applied to. That allows them to produce extraordinary results that also show up in silhouettes and shadows. On the other hand, displacement maps can be more difficult to work with and take much more computing power and time to render.
