POV-Ray : Newsgroups : povray.advanced-users : Lambertian (ideal diffuse) reflectance: how? Server Time
25 Nov 2024 07:30:49 EST (-0500)
  Lambertian (ideal diffuse) reflectance: how? (Message 1 to 3 of 3)  
From: ondrej drbohlav
Subject: Lambertian (ideal diffuse) reflectance: how?
Date: 13 May 2003 16:55:05
Message: <web.3ec15aa5dc541ef51c4385900@news.povray.org>
I wonder how the ideal diffuse (Lambertian) surfaces are defined in
POVRAY. The 'obvious' way seemed to be to define a finish
with diffuse=1, but what about the brilliance parameter --
does Lambertian model correspond to some particular value of brilliance?

Thanks for any suggestion.


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From: Matti Karnaattu
Subject: Re: Lambertian (ideal diffuse) reflectance: how?
Date: 13 May 2003 22:00:07
Message: <web.3ec1a15aaae741bcbef0bd7d0@news.povray.org>
>I wonder how the ideal diffuse (Lambertian) surfaces are defined in
>POVRAY. The 'obvious' way seemed to be to define a finish
>with diffuse=1, but what about the brilliance parameter --
>does Lambertian model correspond to some particular value of brilliance?

Diffuse reflectance in POV-Ray depends on pigment and diffuse value. I
suggest to set diffuse=1 and set diffuse reflectances to color pigment.
Then it is easy to add reflection to surface reducing diffuse value using
same pigment. Lambertian model use default brilliance value.

Matti


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From: ondrej drbohlav
Subject: Re: Lambertian (ideal diffuse) reflectance: how?
Date: 14 May 2003 11:05:06
Message: <web.3ec25ad1aae741bcaee9e6fb0@news.povray.org>
>Diffuse reflectance in POV-Ray depends on pigment and diffuse value. I
>suggest to set diffuse=1 and set diffuse reflectances to color pigment.
>Then it is easy to add reflection to surface reducing diffuse value using
>same pigment. Lambertian model use default brilliance value.

Thanks, it seems that it works. I also checked directly in the code
and found that diffuse intensity is ~ (N.L)^brilliance.

Ondrej


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