Voxel

Voxel

A voxel represents a value on a regular grid in three-dimensional space. As with pixels in a bitmap, voxels themselves do not typically have their position (their coordinates) explicitly encoded along with their values. Instead, the position of a voxel is inferred based upon its position relative to other voxels (i.e., its position in the data structure that makes up a single volumetric image). In contrast to pixels and voxels, points and polygons are often explicitly represented by the coordinates of their vertices. A direct consequence of this difference is that polygons are able to efficiently represent simple 3D structures with lots of empty or homogeneously filled space, while voxels are good at representing regularly sampled spaces that are non-homogeneously filled.

History

The term voxel is a portmanteau of "volume" and "pixel" where pixel is a portmanteau of "picture" and "element". The term has been used at least as early as 1980 by researchers at Xerox PARC, including Robert A. Drebin, Loren Carpenter, and Pat Hanrahan.

Applications

Voxels are frequently used in the visualization and analysis of medical and scientific data. Some volumetric displays use voxels to describe their resolution. For example, a CT scan might be of a 512×512×512 voxel volume, with each voxel representing a 1 mm cube of material that the scanner captured.

Voxels have also been used in video games, where they sometimes allow for more detailed and realistic terrain and environments than heightmaps or polygons.

Voxel Rendering

Voxel rendering is a technique used in computer graphics that utilizes voxels (instead of polygons) to represent a 3D object. The advantage of this approach is that it allows for a very high level of detail and control over the structure of the object.

See also

• Pixel
• 3D computer graphics
• Volume rendering
• Volumetric lighting
• Volumetric fog
• Volumetric path tracing