chefboss nous apporta ses lumieres en ce 2007/08/15 11:25:
> I might like to have the transparent matter behaving like in the real world,
> to visualize some effects and therefore obeying the laws of nature. Scenery
> would not be very complicated and anyhow auto-generated (therefrom the
> perl-driving manner (perl reading eg. from fortran-output)).
> 
> Before I have to implement it in _new_, here what I intend to do:
>   - have _lots_ of objects, each with refraction _and_ reflection _and_
> absorption
>        of some colors
>   - (refraction, absorption, reflection) _not_ the same for all the objects
>   - light passing lots of those objects, not just one or two
>   - embed the objects in each other, with the different ior and
> reflectivities in
>      action (as for (simple) example inside of a sphere of given ior lots of
>      smaller spheres with _different_ ior's (smaller or bigger), thereby
> giving
>      a lot of total-reflections and so on)
> As you see, the above is quite impossible to be faked by any "effects" and
> has to be traced physically. Of course it would use a lot of computing
> power and I didnt say povray were bad ... .
> 
> By the way: How comes that as the author of this question-page does appear a
> "Christian Froeschlin" (see http://news.povray.org/povray.general/ )?
> He gave only a tiny comment, and I did author it (as it seems to me)(i'm
> just asking).
> 
> 
> 
> 
> 
> 
> 
For that, you will need to bump up max_trace_level, possibly to it's maximum of 256.
To show the effect of light comming trough, your only choice will be to use 
photons and make all transparent ana all reflective objects photons targets.
To make things more realistic, you'll need to add some dispersion, in addition 
of the ior, to the interior.
To reproduce the internal coloration, you'll need to use 
fade_color/fade_distance instead of just coloring the object's surface.
To prevent black spots, you may need to change adc_bailout to a somewhat larger 
value than the default of 1/256.
As you project to have many "active" objects, your photons count will become 
very high: probably over 100 000 000!
Photons computations will be prety long. It will also use a big chunk of memory.

If you have some lense like objects and want them to actualy project images of 
other objects on some close by surface, you'll need LOTS of samples.
This will require even more time, and still more memory.

Just hoping that you have a powerfull CPU(s)/FPU(s) and tons or RAM.
If on multicore or multiprocessor, try the beta 3.7 to be able to benefit from them.

-- 
Alain
-------------------------------------------------
Educate and inform the whole mass of the people... They are the only sure
reliance for the preservation of our liberty.
Thomas Jefferson

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