[Radiance-general] gloss and area light source rendering problem

[Jack de Valpine]

Hi Xian,

Interesting surface geometry you have there. Based on your material 
description though the results you are getting seem to be fine. The 
so-called "noise" that you are seeing is the specular highlights based 
on the material that you defined. The plastic material that you defined 
only has a specular component you have left the roughness parameter set 
to 0, thus you material is "shiny" so you are getting the tightly 
defined specular highlights on the bumps of the geometry.

If you want a "glossy" (not sure exactly what you mean here as this 
covers a variety of things) finish, then you should add a roughness 
parameter, for example, you could try out the following for starters 
(this is not based on anything in particular) to see what the difference is:

The bumpy surface is made of the following material:
void plastic gray_plastic
0
0
5 .2 .2 .2 .1 .1

I would try this out with the parameters that you have and see what you 
get. As an additional experiment you may also want to turn on true 
random monte carlo sampling by setting -u+, though this may require that 
you oversample your image at a higher size.

-Jack

PS - what does the geometry represent?

Yun-Xian Ho wrote:
> Hi All,
>
> I have been having problems rendering a glossy bumpy surface composed 
> of intersecting ellipsoids illuminated under a rectangular light 
> source. The image appears to contain some random point source 
> reflections on the surface in addition to the direct reflection of the 
> area light.
>
> To view the rendered image, see: 
> http://homepages.nyu.edu/~yxh201/bumpysurftest.jpg.
>
> The bumpy surface is made of the following material:
> void plastic gray_plastic
> 0
> 0
> 5 .2 .2 .2 .1482 0
>
> and a 30x24 flat rectangular light source is defined as:
> void light bright
> 0
> 0
> 3 25 25 25
>
> I use the following parameters to render the scene:
> -ab 2 -aa .08 -ad 1024 -as 512 -av .2 .2 .2 -sj 1 -st .01 -dj 1 -ds .05
>
> Any suggestions to clean up the "noise" in the image? Much thanks...
>
> --xian
>
>
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>

-- 
# Jack de Valpine
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