Tuesday 7 December 2010

Radiosity and Ray-tracing

Radiosity is a rendering technology that realistically simulates the way that light interacts with environments, by more precisely simulating the light in a scene, radiosity offers more benefits over standard lighting.
Radiosity technology produces more accurate photometric simulations of the lighting in a scene. Effects such as indirect light,soft shadows and color bleeding between surfaces produce images that look natural that are not possible with standard rendering. these images give you better, more realistic ideas of how your designs will look under certain lighting conditions.
Radiosity Comparison
Photometry is the science of measurement of light, in terms of its perceived brightness to the human eye, it is measured in Lumens, candeles, lux and more.
Local illumination algorithms describe only how individual surfaces reflector transmit light. Given a description of light hitting a surface these mathematical algorithms, in 3DSMAX there called shades, predict the color, intensity and the distribution of the light leaving that surface. in conjunction with a material description, different shaders will determine different things like roughness and if the object is metal or plastic. After finding out how the surface reacts to with the light the next task is to figure out where the light hitting the object originates.
algorithms that take into account the ways in which light is transferred between surfaces in a model are called global algorithms

 an algorithm is a mathematical function, a definate list of well defined instructions for completing a task.
the two main algorithms for global illuminination are ray-tracing and radiosity
The Ray-tracing algorithm realises that although there are billions of photons in the air, the photons we need are the ones that enter the eye. the algorithm works backwards by tracing rays from each pixelon the screen to the 3D model, in this way we get only the information needed to construct the image 

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