"John Pye" <nomail@nomail> wrote:
> Hi all
>
> I have an application for POVRAY that seems a little different from what
> most users are doing, and it doesn't seem to be something that's directly
> addressed in the documentation, so I wonder if anyone could offer any
> suggestions.
>
> I'm trying to assess the imaging properties of a number of reflectors. This
> means that I want to create some geometry for a set of mirrors including
> scattering,  geometric surface imperfections, etc, then I want to create a
> light source in the form of a 'sun shape', then I want to see what the
> resulting light intensity at my target plane becomes.
>
> The normal use of POVRAY seems to revolve around the idea of a 'camera'
> which is a single point 'observer'; Raytracing in this case means tracing
> *backwards* from the eye of the beholder to the different spots in the
> scene.
>
> My use seems a bit different: I want to have an imaging plane and I want to
> 'catch' rays over that plane. The overall result should be data about the
> intensity of light striking various points on my imaging (target) plane.
>
> Obviously I can approximate this analysis by creating an imaging plane, and
> then creating a camera that looks at that imaging plane. This won't always
> be practical however, as sometimes the act of creating a visible barrier at
> the imaging plane will cause the optics of the problem to change, eg by
> creating repeated reflections when none are desired.
>
> So, can anyone offer any suggestions on how one my start out with using
> POVRAY in this case?
>
> Finally, is there any way that POVRAY can generate output that shows the
> location of rays in 3-D space? For example if I create a ray-trace any only
> wish to trace a couple of hundred rays, is there any way I can view the
> paths taken by those rays through my scene?


Hi John, I don't have a complete answer, but one idea came to mind.
POV-Ray's 'radiosity' feature traces rays from an object out into the scene
after the camera ray hits it. POV-Ray 'Radiosity' applies to diffuse
objects, and specular reflection is already handled by reflective objects.
This seems to me related to what you're looking for.

Render on,
George

---
MegaPOV XRS: render faster than light!
http://www.gammaburst.net/xrs

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