At my work, we use a software called Lumiscaphe Patchwork 3D and it has an interesting feature in its material editor for real-time 3D. It’s a “relief” parameter that seems to be based on a parallax principle. The effect looks like displacement mapping, except at the borders of the object.
When zooming in on the surface of an object with this effect, one can slightly perceive it as a superposition of layers; for example, for a pyramidal volume, it would be a stack of increasingly smaller squares. But unlike Displacement Mapping it is not necessary to have a high density of vertices, and the effect does not really distort the object > So the silhouette breaks the magic as with the use of a normal map.
Fur is often represented in real time as a stack of 3D surfaces with different opacity textures. The principle is the same but the difference is that here there is only one surface and it is the parallax effect that simulates these different layers. At a “normal” distance from the object, the rendering is impressive. If I don’t think this is a good way to render fur, it could be very powerful for a lot of different things.
As an exemple : on a chesterfield armchair, if we use this to represent the bumped effect we could see the buttons disappear inside each leather holes when passing from the front to the profil view. It’s impossible to do this with a Normal Map !
To configure this effect, you just have to fill in a black and white texture (with grey as a null value), exactly as for Displacement, and fill in a depth value.
Is this material system known outside of Patchwork 3D? Would it be possible to see an equivalent system coming on Sketchfab one day?