[Radiance-general] Surfaces Roughness and simulation parameters

[Jack de Valpine]

Hi Giovanni,

I think that what you need to look at is actually specular jitter and 
threshold (-sj and -st), -ms is for something unrelated assuming I 
remember correctly.

Another factor that can contribute to the appearance of a "pattern" 
(sort of striated) in material with specular and roughness components is 
that fact that Radiance use pseudo random sampling. One way to make this 
go away (albeit at some expense in terms of compute time as well as 
requiring higher image oversampling) is to use the -u switch for 
uncorrelated monte carlo sampling.

Best,

-Jack

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# Jack de Valpine
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#
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On 7/12/2011 2:43 PM, Giovanni Betti wrote:
> Dear List,
>
> I was trying to simulate the visual appearance of brushed alluminum, but
> I am struggling with the roughness of the materials.
>
> I am using metal and metal2 at different roughness settings, but I
> always seem to get a pattern in the roughness of the material, I was
> wondering if any other rpict parameters affect the material behaviour.
>
> My current suspects are:
>
> -ad   Set the number of ambient divisions to N
> -as   Set  the number of ambient super-samples to N
> -ms	Set the medium sampling distance to sampdist
>
> does anybody has some insight in this?
> Thanks,
>
> Giovanni
>
>
> ////////////////////////////////////////////////
> Giovanni Betti
>
>
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