Micro Polygon Displacement
Posted by Ole on Saturday, April 08, 2006 (GST)
Originaly posted by Mark Curtis
"Micro poly displacement is where the render generates additional polygons at render time to simulate smaller details than could be shown on the base mesh.
Previous to LW-9, LW was only able to displace what polygons appeared in the scene, if you want smaller displacements you had to subdivide the mesh further prior to rendering. Renderers such as Vray for MAX or Mental Ray (and apparently Modo 201) are able to look at the displacement map and work out where to apply local subdivision in order to achieve the detail of the displacement map.
In Vray it is a common trick to apply a very fine fractal texture as a displacement map to a single polygon in order to simulate short grass for architectural renders.
Because this is actual geomtry it is far more accurate than normal maps (silhouettes are correct and the displacement can cast shadows), but it isn't quite as fast (depending on the ammount of additional geometry that needs to be created)."