Computer rendering

In 3D computer graphics, rendering is the process of drawing a 2D image, based upon a description of a three-dimensional scene (which may include geometry and material properties). It is a slow, computationally intensive process (typically for moviecreation) or supported by realtime 3D hardware accelerators in graphiccards (typically for 3D computer games). The term is by analogy with an "artist's rendering" of a scene.

When the pre-image (a wireframe sketch usually) is complete, rendering is used, which adds in textures, lights, bump mapping, and relative position to other objects. The result is a completed image the consumer or intended viewer sees.

For movie animations, several images (frames) must be rendered, and stitched together in a program capable of making an animation of this sort. Most 3-D image editing programs can do this.

There are a number of different phenomena that need to be simulated when rendering a scene:

• diffuse reflection[?]
• specular reflection[?]
• refraction
• global illumination
• depth of field
• motion blur
• diffraction

All of these effects can be summed up in a single 'rendering equation' that contains very complex constants that in effect encode the scene.

All 3-D rendering software and hardware produces an approximation to a solution of the idealised rendering equation. Slow moviecreation software typically use more realistic rendering equations than realtime 3D hardware accelerators.

Methods of rendering include:

• the painter's algorithm
• Ray tracing
• Global illumination
• Radiosity
• Scanline algorithms
• Z-buffer algorithms[?]

Movietype rendering often takes place on a network of tightly connected computers called a render farm.

The current state of the art in 3-D image description for movie creation is the RenderMan scene description language[?] designed at Pixar. (compare with simpler 3D fileformats such as VRML or APIs such as OpenGL and DirectX tailored for 3D hardware accelerators).

Movie type rendering software includes:

• PRman[?]
• POV-ray
• Mental Ray[?]
• Blender (which can also be used to produce a scene to be rendered)

Fill in research - image based rendering, non photorealism, etc.

External links:

• http://www.povray.org/