Editing Scientific visualization (section)

=== Surface rendering ===
[[Rendering (computer graphics)|Rendering]] is the process of generating an image from a [[3D model|model]], by means of computer programs. The model is a description of three-dimensional objects in a strictly defined language or data structure. It would contain geometry, viewpoint, [[texture mapping|texture]], [[lighting]], and [[shading]] information. The image is a [[digital image]] or [[raster graphics]] [[image]]. The term may be by analogy with an "artist's rendering" of a scene. 'Rendering' is also used to describe the process of calculating effects in a video editing file to produce final video output. Important rendering techniques are:

;[[Scanline rendering]] and rasterisation
: A high-level representation of an image necessarily contains elements in a different domain from pixels. These elements are referred to as primitives. In a schematic drawing, for instance, line segments and curves might be primitives. In a graphical user interface, windows and buttons might be the primitives. In 3D rendering, triangles and polygons in space might be primitives.

;Ray casting
: [[Ray casting]] is primarily used for realtime simulations, such as those used in 3D computer games and cartoon animations, where detail is not important, or where it is more efficient to manually fake the details in order to obtain better performance in the computational stage. This is usually the case when a large number of frames need to be animated. The resulting surfaces have a characteristic 'flat' appearance when no additional tricks are used, as if objects in the scene were all painted with matte finish.

;Radiosity
:[[Radiosity (computer graphics)|Radiosity]], also known as Global Illumination, is a method that attempts to simulate the way in which directly illuminated surfaces act as indirect light sources that illuminate other surfaces. This produces more realistic shading and seems to better capture the '[[available light|ambience]]' of an indoor scene. A classic example is the way that shadows 'hug' the corners of rooms.

;Ray tracing
:[[Ray tracing (graphics)|Ray tracing]] is an extension of the same technique developed in scanline rendering and ray casting. Like those, it handles complicated objects well, and the objects may be described mathematically. Unlike scanline and casting, ray tracing is almost always a Monte Carlo technique, that is one based on averaging a number of randomly generated samples from a model.