DISPLACEMENT MATERIAL
Materials can be used for color, bumps, or displacement. The difference between bumps and displacement is that bumps only affect the appearance of the surface, while displacement actually changes the shape, but displacement has many caveats compared to bumps. Bumps can have lots of detail but displacement depends on the density of the mesh. This means the model should have many more patches than normally necessary when displacement is going to be used. Often both bump and displacement materials are applied (“water” for example). Displacement is used to make a surface’s profile uneven, and bumps add the detail. Displacement also generally takes longer to render and uses more memory.
To make a material displace, in the material’s Properties, set the “Displace Percent” to a value other than “0”. The material will not color the model it is applied to but instead use its grayscale value to displace the surface. Where the material is darker than median gray, the surface will go in away from the normal, and where the material is lighter than median gray, the surface will go out along the normal.