Thomas Lake wrote in message <369BE55C.F4625028@home.com>...
>I have another good way to model LED's
[snip]
>What you
>do is create, using CSG's a small room behind where you want the LED to be,
make
>this room have a 100% reflective texture. Then cut a small hole the shape
of the
>LED from the hole to the surface of you object.
[snip]

That idea seems sound at first glance, but when viewed with the mechanics of
a raytracer (and especially POV-Ray) in mind, one sees, that it is not the
best solution to the problem: The outcome may be the one that is wished for
(as can be seen in the image you posted), but for the wrong reasons, and at
the cost of increased rendertime.

I'll try to explain why:

I see why you would go for 100% reflectiveness: Because it would model
reality closest, with the "small room" catching the light of the lightsource
and casting it all out of the little hole, like the reflector of a lamp,
making the LED shine brightly.

Only this doesn't work in POV-Ray :-)

If it would, then POV-Ray would be able to do specular reflection / indirect
lighting, which it can't do (if you don't count the very interesting project
Nathan Kopp has in the works).
So using the 100% reflection has only one effect: Pushing up render time
unnecessarily, but the visible outcome of the image will not be changed by
it.

Instead you could simply:
a) Color the walls of the "small room" white and let the colored lightsource
make them appear in the right color, or
b) Color the walls of the "small room" in the color of the LED and use a
white lightsource, or... :

Actually, if you don't want to have the LED to throw light on anything (like
in your rendered image, where the LEDs are only seen as bright spots, but do
not throw light on anything), then it would cut down on rendertime even
more, if you leave out the light source totally, which leaves option "c"
(quite close Ken's suggestion):

c) Color the walls of the "small room" in the color of the LED and give them
a high ambient value, don't use a lightsource at all...

Please excuse my dismissal of your otherwise very creative idea :-) but I
thought it would save some people some time if I explained a bit...

So long,
Johannes.

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