I'm using POV as a raytracing program for DIALux. I'm trying to light a very
big billboard thats about 20m wide by 25m high. After a lighting
calculation, I jump to raytracing. Some of the results produce weird
lights.

http://gallery.cybertarp.com/albums/userpics/13594/DIALux.jpg

Thaks for any help.
Robin

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in news:web.40907f86eb41d4117223836a0@news.povray.org erona wrote:

> Some of the results produce weird
> lights.
> 
> http://gallery.cybertarp.com/albums/userpics/13594/DIALux.jpg
> 

The light spots are a result of the radiosity calculation. I'm not sure 
what causes it exactly, but I noticed it happens when you have an object 
with a high ambient finish close to a "wall". 

The colourfull background in this old post is based on that effect:

Newsgroups: povray.binaries.images
Subject: Them radiant little devils ....       [~67KB]
Message-ID: <Xns### [at] povrayorg>
Date: 24 Mar 2001 05:04:08 -0500
Xref: news.povray.org povray.binaries.images:48211

http://news.povray.org/Xns906E70D695CF9seed7@povray.org

Ingo

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ingo <ing### [at] tagpovrayorg> wrote:
> in news:web.40907f86eb41d4117223836a0@news.povray.org erona wrote:
>
> > Some of the results produce weird
> > lights.
> >
> > http://gallery.cybertarp.com/albums/userpics/13594/DIALux.jpg
> >
>
> The light spots are a result of the radiosity calculation. I'm not sure
> what causes it exactly, but I noticed it happens when you have an object
> with a high ambient finish close to a "wall".
>
> The colourfull background in this old post is based on that effect:
>
> Newsgroups: povray.binaries.images
> Subject: Them radiant little devils ....       [~67KB]
> Message-ID: <Xns### [at] povrayorg>
> Date: 24 Mar 2001 05:04:08 -0500
> Xref: news.povray.org povray.binaries.images:48211
>
> http://news.povray.org/Xns906E70D695CF9seed7@povray.org
>
> Ingo

Sorry but its a dead link. Anyways, do you mean I have to move the billboard
farther from the wall? Thanks

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in news:web.4092248288f09a9e167c3a6e0@news.povray.org erona wrote:

> Sorry but its a dead link.

If you get on a page that talks about cookies and settings etc, go to the 
bottom of it and klick ok. After that the right page will pop up.

> Anyways, do you mean I have to move the
> billboard farther from the wall? Thanks

Objects with a ambient in their finish act as if they light up when 
radiosity is used.  First make sure that the billboard has and ambient 0 
and a diffuse >0 <1 in your finish statement. If that makes the board to 
dark, you can light it up with a fill-light using projected_through.

If that does not improve things, you can try to move the board a bit from 
the wall.


Ingo

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