The Composite material node mixes several materials using masks (figure 1). This is much cleaner than using several chained Mix materials. If a mask is not connected, the material's Opacity is used. The first MaterialThe representation of the surface or volume properties of an object. pin becomes the base layer.
Figure 1: A Composite material node used to mix a red and blue Diffuse materialUsed for dull, non-reflecting materials or mesh emitters. with a Checks node as a mask
Add Input - Adds a new Material input to the end of the node.
Remove Input - Removes the last Material input.
DisplacementThe process of utilizing a 2D texture map to generate 3D surface relief. As opposed to bump and normal mapping, Displacement mapping does not only provide the illusion of depth but it effectively displaces the actual geometric position of points over the textured surface. - Displacement for the Composite Material surface.
Custom AOV - Writes a mask to the specified custom AOV.
Custom AOV Channel - Determines whether the custom AOV is written to a specific color channel (R, G, or B) or to all the color channels.
Material - The Material input. When several MaterialsA set of attributes or parameters that describe surface characteristics. are used, the first Material pin becomes the base layer.
Material Mask - Controls the Material’s opacity using an Input map. If a mask is not connected, the Material's opacity is used.