The 3d Displacement Shader

As I’m working on the new Sub-Surface Scattering tutorial I thought I would break off a small piece and make it an independent post. Below I’ll provide a visual guide to the parameters in the 3d Displacement Shader in 3d Studio Max mental ray. It’s pretty straightforward but there are some interesting things you might not have known you can do with it!

The 3d Displacement Shader Controls

Object Independent

When this is turned on the displacement effect is independent of the size of the object’s bounding box. When it’s off the displacement effect is scaled according to the size of the object.  Scaling the displacement based on object size is the standard behavior for regular 3ds Max displacement mapping so if you leave this checkbox checked then the displacement length will behave like a normal material would.

Left has Object Independent enabled. Right does not.

Displacement Length

This is the length of displacement when Object Independent is checked, the extrusion map is at 100 percent (white), and the Extrusion Strength equals 1.0. Lower gray levels in the extrusion map, or other values of Extrusion Strength, scale the amount of displacement.  Think of this as a way to alter the displacement map’s contrast.

0.083 (default), .25, and .35 displacement lengths

Extrusion Strength

Controls the height of the displacement. This value is a multiplier: at the default value of 1.0, the map’s effect is unchanged. Greater values will make the displacement more severe while lower values will make it more subtle.

1, .5, and 1.5 extrusion strengths

Extrusion Map

Click to display the Material/Map Browser and choose a map to use for the displacement. Displacement maps apply the gray scale of the map to generate the displacement. Lighter colors in the 2D image push outward more strongly than darker colors, resulting in a 3D displacement of the geometry.

Checker map, dent map, marble map

Direction Strength

Controls the strength of the direction shader.  Adding a direction shader has no real effect unless you have the Direction Strength set above zero.

0, 1, and 2 direction strength values

Direction Map

The direction map is a lot like a normal map.  The direction of the displacement is changed according to the RGB values of the map you use here. Red values offset in the U axis, Green values offset in V, and Blue values offset in W (using the object-local UVW coordinates).

Checker patterns, Red/Green, Red/Blue, Green/Blue