Re: backward ray tracing

On Feb 21, 10:32 am, surface2air <johnnas...@xxxxxxxxx> wrote:
can any on explain what this phenomenon actually is and why its better
than forward ray tracing.

If you are referring to it from a computer graphics perspective,
backward ray tracing is a technique where rays are launched from the
viewer into the scene and the intersections with objects and light
sources is tracked to determine what the eye can see. This way only
rays that are known to enter the eye will be traced.

When you use forward ray tracing, you initiate rays from the light
source and then trace it through the scene. Not every ray from the
light source will make it into a view camera, in fact very few will
actually make it into the view camera so you will need to trace
hundreds of millions of rays to get enough information into the camera
using this technique.

Forward ray tracing has the advantage of theoretically being able to
accurately capture any optical phenomenon like scattering, color
shifting, and caustics. Backward ray tracing can't necessarily handle
these things well if at all. Backward ray tracings advantage is it's
speed and efficiency. You get a good enough image very quickly.

.

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