2.5D

= 2.5D =

"Two and a half-D" is an optimization trick for RT3D that fakes the viewer into thinking they are seeing true 3D graphics. A whole scene (or an object in a scene) is made of 2-dimensional graphics that are scaled and drawn in perspective to look like polygonal graphics, but there are no polygons involved. The groundbreaking game Doom is built entirely on this concept. Billboards are 2.5D, but voxels can be either 2.5D or 3D.