In computers, 3-D (three dimensions or three-dimensional) describes an image that provides the perception of depth. When 3-D images are made interactive so that users feel involved with the scene, the experience is called virtual reality. You usually need a special plug-in viewer for your Web browser to view and interact with 3-D images. Virtual reality experiences may also require additional equipment.
3-D image creation can be viewed as a three-phase process of: tessellation, geometry and rendering. In the first phase, models are created of individual objects using linked points that are made into a number of individual polygons (tiles). In the next stage, the polygons are transformed in various ways and lighting effects are applied. In the third stage of 3D modeling, the transformed images are rendered into objects with very fine detail.
Popular products for creating 3-D effects include Extreme 3D, LightWave 3D, Ray Dream Studio, 3D Studio MAX, Softimage 3D, and Visual Reality. The Virtual Reality Modelling Language (VRML) allows the creator to specify images and the rules for their display and interaction using textual language statements.
See a tutorial on 3-D modeling: