The **Persistence of Vision Ray-Tracer**™, or **POV-Ray**, is a free ray tracing program available for a variety of computer platforms. It was originally based on DKBTrace, written by David K. Buck and Aaron A. Collins. There are also influences from the earlier Polyray raytracer
contributed by its author Alexander Enzmann.
It is freeware, and although it is not open source, the source code is available under the POV-Ray License. According to the documentation for the Windows version:

Without a doubt, POV-Ray is the world's most popular raytracer. From our website alone we see well over 100,000 downloads per year, and this of course doesn't count the copies that are obtained from our mirror sites, other internet sites, on CD-ROM, or from persons sharing their copies.

Table of contents |

2 Current Version 3 Development and Maintenance 4 Caveats 5 External Links |

## Features

- A Turing-complete scene description language that supports macros and loops.
- Support for Constructive Solid Geometry modeling
- Library of ready-made scenes, textures, and objects
- Support for a number of geometric primitives
- Several different kinds of light sources
- Atmospheric effects such as fog and smoke
- Reflections, refractions, and light caustics using photon mapping
- Surface patterns such as wrinkles, bumps, and ripples, for use in procedural textures and bumpmapping
- Robust image format support for textures and render output: TGA, PNG, JPEG (only input), just to name a few.
- Excellent documentation

### POV-Ray primitives

POV-Ray, in addition to ordinary shapes like tori, spheres and heightfields supports exotic mathematically defined primitives such as the isosurface (a finite approximation of an arbitrary function), the polynomial primitive (an infinite object defined by a 15th order or lower polynomial), the julia fractal (a 3-dimensional slice of a 4-dimensional fractal), the superquadratic elipsoid (a cross between a sphere and a square), and the parametric primitive (using equations that represent its surface, rather than its interior).

POV-Ray internally represents objects using their mathematical definition; all POV-Ray primitive objects can be described by a mathematical function. This is somewhat in contrast to many other 3D computer modeling packages, which typically use triangle meshes to compose all objects.

This fact provides POV-Ray with several advantages over other rendering / modeling systems. POV-Ray primitives are often smoother and more mathematically accurate than their polygonal counterparts. Objects that can be described in terms of spheres, planar surfaces, cylinders, tori and the like are perfectly smooth and mathematically accurate in POV-Ray renderings, whereas polygonal artifacts may be visible in mesh-based modeling software. POV-Ray primitives are also simpler to define than most of their polygonal counterparts. In POV-Ray, a sphere is described simply by its center and radius; in a mesh-based environment, a sphere must be described by a multitude of small polygons.

## Current Version

The current official version of POV-Ray is 3.5. Some of the main features of this release:

- UV texture mapping in tandem with an improved mesh primitive (using the 'mesh2' keyword)
- Photon mapping, which provides realistic rendering of light caustics
- Isosurfaces, which directly render surfaces defined by a mathematical function
- Functions that, among other things, can be used for generating new patterns for isosurfaces, for parametric surfaces etc.

## Development and Maintenance

Official modifications to the POV-Ray source tree are done and/or approved by the POV-Team^{TM}. Parties interested in patch submission and/or bug reporting should join the POV-Ray newsgroups on the povray.org news server.

For those impatient for new features, there are unofficial forks and patched versions of POV-Ray available from third parties; however, these are not officially supported by the POV-Team^{TM}.

## Caveats

## External Links

- http://www.povray.org/ - POV-Ray homepage
- news://news.povray.org/ - POV-Ray news server
- http://news.povray.org/ - Web access to POV-Ray news server
- comp.graphics.rendering.raytracing - Usenet newsgroup popular with POV-Ray users (or POV-Ray is a frequent topic)
- http://www.irtc.org/ - International Raytracing Competition, where POV-Ray artists have submitted many outstanding images

### Unofficial Patches

- http://megapov.inetart.net/ - MegaPOV, a collection of unofficial extensions of POV-Ray.
- http://staff.aist.go.jp/r-suzuki/e/povray/iso/df_body.htm - The Density_File Extension patch
- http://jgrimbert.free.fr/pov/patch/tessel/ - Tesselation patch
- http://www.aetec.ee/fv/vkhomep.nsf/pages/POVMan2 - This custom version allows to describe POV-Ray object pigments with procedural code, compatible with RenderMan (R) Shading Language.