tsachi nous illumina en ce 2008-11-23 14:23 -->
> I am currently working on a UTD MOM hybrid solver.
> This is a solver for an electromagnetic waves that uses an hybrid method between
> geometrical optics and direct solving of the maxwell equations.
> In the part of the geometrical optics I am planning to use direct ray tracing
> (source to camera/point of measurement).
> My brother suggested I consult this website, and use parts of the ray tracer as
> a base for my program.
> I have encountered a problem understanding direct ray tracing.
> Unlike in backward ray tracing, the number of rays entering every pixel is not
> fixed (depends on the geometry and the density of the incoming rays).
> Say I double the incoming ray density so I will get a double number of rays
> hitting every pixel, but the actual number of rays is dependent on the
> geometry.
> So how do I normalize the value inside the pixel?
> Any one knows a good forward ray tracing tutorials that could help me?
> 
> 
You can't do "pure" forward tracing with POV-Ray.
You can do mixed forward/backward tracing when you use the photons feature.

When using that feature, rays are still traced from the camera. Rays comming 
from a light source and passing trough a transparent object, or bouncing off 
reflective objects are calculated, if the objects in question are designated as 
"target".

The rays comming from a light source are evenly spaced. If you double the number 
of rays, each ray will be half the intensity. So, there is a inbuilt normalisation.

-- 
Alain
-------------------------------------------------
Moonies: Only really happy shit happens.

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