The Apply node applies a 3D texture on a surface defined by a heightmap. It can be used to apply several different 3D textures accoding to a color index map.
The Apply node accepts 3 inputs:
the height map defined by a greyscale texture that defines the 3D surface
the color index map defined by a greyscale texture that can be used to define which 3D texture should be applied for each pixel of the result
the 3D texture (or several 3D textures using the Select node)
The Apply node generates a color image where the 3D textures are applied to the surface.
The Apply node does not accept parameters