I need to simulate realistic light effects in diamond-shape structures.
I see no big trouble in making the shape, but i am no sure about
setting material parametres. Also I have heard that raytracing programs are
not good at stuff like this.


--
Rebel
http://zone.wz.cz
sku### [at] hotmailcom

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"J.Kosina (Rebel^v^)" wrote:
> 
> I need to simulate realistic light effects in diamond-shape structures.
> I see no big trouble in making the shape, but i am no sure about
> setting material parametres. Also I have heard that raytracing programs are
> not good at stuff like this.


Diamonds are actually quite easy to simulate in POV-Ray. Raytracing is the
BEST approach of all the 3D graphics program types. The material properties
are rather simple. You will need to make it transparent, set the refraction
index (ior) value to something greater than 2.0, and add a bit of reflection.
Using the photon feature will give even more realistic lighting results. You
should be able to find several examples of gem stones in the scene-files groups
on this server or search for diamonds in the subject line in the images group.

See also - http://jgrimbert.free.fr/pov/objet.html

I also have a diamond generating macro available here -
http://objects.povworld.org/cat/Geometrical_Objects/

-- 
Ken Tyler

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In article <3e22232e@news.povray.org>,
 "J.Kosina \(Rebel^v^\)" <sku### [at] hotmailcom> wrote:

> I need to simulate realistic light effects in diamond-shape structures.
> I see no big trouble in making the shape, but i am no sure about
> setting material parametres. Also I have heard that raytracing programs are
> not good at stuff like this.

I'm not sure where you would have heard that. Raytracers excel at this 
type of thing, reflection and refraction are extremely difficult to do 
accurately in a scanline renderer and very easy in a raytracer. In fact, 
I think this is one of the uses of raytracing that actually predates 
computers, along with lens design.

-- 
Christopher James Huff <cja### [at] earthlinknet>
http://home.earthlink.net/~cjameshuff/
POV-Ray TAG: chr### [at] tagpovrayorg
http://tag.povray.org/

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Christopher James Huff wrote:
>In article <3e22232e[at]news.povray.org>,
> "J.Kosina \(Rebel^v^\)" <sku### [at] hotmailcom> wrote:
>
>> I need to simulate realistic light effects in diamond-shape structures.
>> I see no big trouble in making the shape, but i am no sure about
>> setting material parametres. Also I have heard that raytracing programs are
>> not good at stuff like this.

There is actually some truth to it. Diamond has a very high 'ior' (about
2.4) which causes many internal reflections. It is like once the light ray
enters the diamond, it stays there and only comes out after getting
reflected many times.
Many raytracers (including POV) decide that the light ray is lost after a
certain number of reflections. This is why some portion of your diamond may
look black. Of course, with POV Ray, this is no major problem. You just
have to tell POV that you want to trace for a long time - this is done by
(if I recall correctly) setting the 'max_trace_level' in 'global_settings'.
Hope this helped,
Hirak!

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Thanks, this one realy helped. Other thing is that color dispersion is verry
important in diamonds, and Povray supports this from v.3.5, fortunately:-)
Josef

Hirak wrote:
>Christopher James Huff wrote:
>>In article <3e22232e[at]news.povray.org>,
>> "J.Kosina \(Rebel^v^\)" <sku### [at] hotmailcom> wrote:
>>
>>> I need to simulate realistic light effects in diamond-shape structures.
>>> I see no big trouble in making the shape, but i am no sure about
>>> setting material parametres. Also I have heard that raytracing programs are
>>> not good at stuff like this.
>
>There is actually some truth to it. Diamond has a very high 'ior' (about
>2.4) which causes many internal reflections. It is like once the light ray
>enters the diamond, it stays there and only comes out after getting
>reflected many times.
>Many raytracers (including POV) decide that the light ray is lost after a
>certain number of reflections. This is why some portion of your diamond may
>look black. Of course, with POV Ray, this is no major problem. You just
>have to tell POV that you want to trace for a long time - this is done by
>(if I recall correctly) setting the 'max_trace_level' in 'global_settings'.
>Hope this helped,
>Hirak!
>

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