POV-Ray : Newsgroups : povray.newusers : 'Photon object' : Re: 'Photon object' Server Time
11 Aug 2022 11:30:00 EDT (-0400)
  Re: 'Photon object'  
From: clipka
Date: 25 Sep 2018 10:02:14
Message: <5baa3fe6$1@news.povray.org>
Am 25.09.2018 um 15:18 schrieb Albun:
> 
> here are real subjects or not, on the creation of a "photon object" of Povray
> (not for a Jedi sword ...)

Right now, I can only wildly speculate what you are trying to achieve.

My best bet is that you are trying to place one or more shapes (e.g. a
spheres) in the scenes to illustrate the path a light ray might travel
through (or end up in) the scene, without calculating a bunch of such
paths by hand.


I think you'll have to implement your own ray tracer in POV-Ray's scene
language, using the trace() function; but different from the example
"ray tracer in a ray tracer" code in the docs, instead of classic
backward ray tracing you would have to implement photon mapping (which
is essentially forward ray tracing, starting at the light source); also,
you'd have to add support for refractions if you want to simulate a lens.

If you're only trying to compute the places where a bunch of light rays
would end up (as opposed to the paths traveled), to illustrate their
distribution and density on a target plane, it might also be possible to
export a photon map and load it back into POV-Ray, but it might be
tricky to decode the photon map file.

Instead of exporting the photon map, you could also instead use an
orthographic camera to render the light pattern created by the lens on
the target plane(?), import that back into POV-Ray scene as an image
function, and use that function as a "filter" for randomly placed objects.


Well, that's my interpretation of what you're trying to achieve, anyway,
but...


>  A 'photon object' by exporting the spectral color simulation data, is possible
> with Povray?

... I have no idea how "spectral color simulation data" (whatever you
mean by that) would fit into my current interpretation...

> 2) Another method, from hf_map, in gray scale, allows to obtain a hf_object
> exportable in data.
> *HF_Square(Function, UseUVheight, UseUVtexture, Res, Smooth, FileName, MnExt,
> MxExt).
> But with csg cut on hf_object, is hf_square cut data too?

... or how height fields might come into play.


So I have a hunch that I'm completely misunderstanding what you're
trying to achieve.


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