Alain <ele### [at] netscapenet> wrote:
> 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


thank you, I think I started to understand it.
But still, can you recomend a good toturial in the subject? because I think I
need pure farward raytracing (I am interested in the field every where and not
only at the camera), and every toturial/book I found was about backwards ray
tracing.
> "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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