As already noted, radiosity technique models diffuse reflections between different surfaces in the scene. In order to do this, the fraction of the incident light that each surface reradiates needs to be defined. This is achieved by making use of material shaders. The intention is that materials shaders can be set up in such a way that surfaces are fully specified for both the radiosity simulation and for later rendering, without the need for alteration.
Two information are required for the calculations of radiosity simulation. Firstly, the color of each surface needs to be known, so that effects such as color bleeding are modeled; Secondly, the overall fraction of the light incident on each surface, which will be diffusely re-radiated by that surface, must be specified.
Only two classes of materials can be used during the radiosity solution: color and reflectance. The light re-radiated by a surface is calculated by the multiplication of the diffuse reflection factor provided by a correctly set up reflectance shader and the color value provided by the color shader. Any of the other classes may also be made use of: they will be ignored by Radiosity, but used by those rendering methods to which they apply, when the radiosity solution is rendered.
Once the radiosity simulation is complete, the result can be displayed by rendering the processed geometry as required. The solution can be rendered in any supported rendering methods, such as preview, full, and so on. To enable realistic shading effects to be obtained for these modes, it will be necessary to use materials that will create the relevant effect. Materials shaders such as procedural texture shaders, texture maps, bumpmaps, mirrors, and so forth, can be used to give added realism to the finished image if it is rendered using a high-quality rendering method.
Rendering using a photo-realistic method will allow the above effects, as well as the radiosity solution, to be incorporated into the final image, allowing very high quality images. These will not only exhibit realistic lighting conditions, but also reflections, textures and surface imperfections which all contribute to making an image look real rather than artificial.
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