[Radiance-general] Area lights breaking up?

[Ian Tester]

On Tue, 23 Aug 2005 13:47:15 -0600
Rob Guglielmetti <rpg at rumblestrip.org> wrote:

> Ian Tester wrote:
> 
> >I've tried fiddling with -dj and -ds, and a few other rpict parameters,
> >but they don't seem to do much at all. Is this a bug in Radiance 3.7 or
> >am I doing something wrong? I've never had this problem with area lights
> >in Radiance before.
> >  
> >
> Are you sure?  I'm pretty sure that effect you see is the result of the 
> -ds parameter subdividing your largeish area source into smaller bits.  
> Fiddling with -ds should have changed the number of sources you saw in 
> your reflections.  Setting -ds to 0 turns this off, which you may want 
> to try. 

The problem appears to be with the roughness of the plastic. If it's set
to 0, then reflections are shown. As soon as I increase it to as much 0.01,
the plastic is no longer reflective and all we see is the specular
highlights of the sub-divided area light pieces. Is this the intended
behaviour? I remember spending quite some time fine-tuning these parameters
to look just the way I wanted. Now nothing I can do will bring back the old
appearance. The billiard balls should be glossy but not too smooth.

I wondered if my problems might be to the mixfuncs and such that I use to
produce the billiard balls. So I made a super simple scene to test this
problem and I get the same results. I've attached it to this email. Just
run rad on the test.rif file.

Here is what I get:
http://www.ian.testers.homelinux.net/dump/test_main

The left ball has a roughness of 0.01, the one on the right is 0.

And if the mailing list eats the attachment:
http://www.ian.testers.homelinux.net/dump/spectest.tar.bz2

bye
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