clipka <ano### [at] anonymousorg> wrote:
> Oh, and did you know that the current implementation of brilliance is
> physically bogus?
>
> For virtually all real-world materials, the function that describes how
> much of any given incoming light ray comes out as any other given
> outgoing light ray is a /bidirectional/ one: You can swap incoming and
> outgoing ray, and the equation still yields the same result.
>
> That's not the case for POV-Ray's diffuse surface when using any
> brilliance value other than 1.
>
Yes, ...but I consider this current brilliance has its advantage. It has a
simple mathematics form. For users who want to control their own effect, it is
good.

> This can be fixed however -- and voila: It does provide for pretty neat
> effects.

I heard that there is an oren-nayar model. Is it something like that? If so, it
is very good because difference of diffuse model can creat many variety of
texture. The current pov-ray feature which can do this is not rich. Only
normal{...} on a texture can work with radiosity.


> Left: brilliance 0.7 (using the fixed implementation); this might come
> in handy to model fluffy stuff, such as tennis balls.
>
> Center: brilliance 1.0 for reference.
>
> Right: brilliance 2.0 (using the fixed implementation); should do great
> for black nylons or the like. Might also come in handy as the basis for
> a pearl material I guess.


Brilliance for radiosity is good.

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