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:
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