Node Description and Purpose: The Fake Stones Shader creates a surface displacement that resembles individual stones or rocks. The effect is similar to a rock "population", except that as a surface shader it has global coverage unless restricted. You can control scale and density, shape, and colour. The Fake Stones Shader uses an internal Voronoi-based displacement function to create the rock shapes.
Literally, to change the position of something. In graphics terminology to displace a surface is to modify its geometric (3D) structure using reference data of some kind. For example, a grayscale image might be taken as input, with black areas indicating no displacement of the surface, and white indicating maximum displacement. In Terragen 2 displacement is used to create all terrain by taking heightfield or procedural data as input and using it to displace the normally flat sphere of the planet.
A shader is a program or set of instructions used in 3D computer graphics to determine the final surface properties of an object or image. This can include arbitrarily complex descriptions of light absorption and diffusion, texture mapping, reflection and refraction, shadowing, surface displacement and post-processing effects. In Terragen 2 shaders are used to construct and modify almost every element of a scene.