A 2-D technique of simulating the appearance of a 3-D object in a scene. An application inserts a primitive, typically rectangular, into the scene, oriented so that one face is toward the viewer and applies a texture or a set of textures. The texture or set of textures gives the appearance of an animated 3-D object.
A technique to increase the visual complexity and realism of a virtual environment using complex texture maps displayed on a flat plane, similar to a billboard sign. The trick of this technique is to swivel the front of the billboard so that it is always facing the participant. Billboarding is one way to make realistic looking worlds with low numbers of polygons.