In this material and rendering tutorial the ability to vary the degree of surface roughness according to view angle is explored. This is a powerful technique that simulates real world material properties which can be useful for architectural and product/package design.
Here are some links to an architectural website which demonstrate examples of the technique from this tutorial.
Example 1. Note the ceiling.
Example 2. Note the floor. It’s very rough with only a hint of glossiness near the lower part of the image, but at the distant end of the scene it’s more glossy.
Example 3. Compare the wood floor of this scene where the camera is low to the ground (high incidence) against another photo of the same scene but at a higher view angle (low incidence).
Example 4a, Example 4b: Note the wood floors.
Compare to this scene where the floor has a fairly uniform degree of roughness. It’s quite glossy without regard to incidence angle. But the degree of reflectivity does increase with incidence.
