Sorry to ask this (maybe stupid and denoting a total lack of knowledge on
how POV-Ray works) question, but is it possible to gather and dump to a
file raytracing informations during the raytracing process, for example by
using SDL ?

I think for example of the possibility to gather for each ray the initial 3D
vector parameters of this ray from the camera, and then to get the end 3D
vector after the raytracing process for this ray (and/or the point in the
"world" where it gets).

I would like to use POV-ray to gather informations about the effects of
refraction of a "complex" scene mainly made of transparent objects. Is it
possible ?

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magnum nous apporta ses lumieres ainsi en ce 29/07/2004 08:31... :

>Sorry to ask this (maybe stupid and denoting a total lack of knowledge on
>how POV-Ray works) question, but is it possible to gather and dump to a
>file raytracing informations during the raytracing process, for example by
>using SDL ?
>
>I think for example of the possibility to gather for each ray the initial 3D
>vector parameters of this ray from the camera, and then to get the end 3D
>vector after the raytracing process for this ray (and/or the point in the
>"world" where it gets).
>
>I would like to use POV-ray to gather informations about the effects of
>refraction of a "complex" scene mainly made of transparent objects. Is it
>possible ?
>
>
>  
>
Using photons will show you where the light goes after the diffraction. 
Set a light_source to emit photons and set your transparent objects as 
target with refraction on. You need some surfaces for the photons to 
show on. Be ready for a prety long render.
Look at section 3.5.3 in the documentation to set your photons scene.

Alain

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Wasn't it magnum who wrote:
>Sorry to ask this (maybe stupid and denoting a total lack of knowledge on
>how POV-Ray works) question, but is it possible to gather and dump to a
>file raytracing informations during the raytracing process, for example by
>using SDL ?
>
>I think for example of the possibility to gather for each ray the initial 3D
>vector parameters of this ray from the camera, and then to get the end 3D
>vector after the raytracing process for this ray (and/or the point in the
>"world" where it gets).
>
>I would like to use POV-ray to gather informations about the effects of
>refraction of a "complex" scene mainly made of transparent objects. Is it
>possible ?

You can certainly use trace() to follow a ray to where it first hits
something. (Hint: group all your refractive objects into one union and
all your opaque objects into another, trace them both and then use
vlength() to see which one is hit first.)

I guess you'd have to do the refraction calculations explicitly in SDL.
Trace() will give you the direction of the normal at the intersection
point. I's a long time since I did O-level physics, but I seem to
remember that the ratio of the sin of the angles is equal to the ratio
of the refractive indices.

-- 
Mike Williams
Gentleman of Leisure

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