POV-Ray : Newsgroups : povray.beta-test : Media Photons Server Time
28 Jun 2024 02:40:52 EDT (-0400)
  Media Photons (Message 1 to 6 of 6)  
From: Christian Froeschlin
Subject: Media Photons
Date: 7 Aug 2010 20:24:39
Message: <4c5df947$1@news.povray.org>
I played a bit with these today and encountered some issues:

1. It seems photons from cylindrical light sources are no
    longer deposited in media with 3.7

2. When using spot lights it worked but with identical
    settings the beam of light was much stronger/wider in
    3.7 than it was with 3.6

3. When adding "no_reflection" to media container, the
    reflection for the beam of light prior to hitting the photon
    target was suppressed but reflection of the photon beam itself
    was not suppressed (this problem occurs also in 3.6).

A test scene for points 1 and 2 is attached, images in p.b.i.

Furthermore, media photons were not deposited in 3.6
when the light source was set to "refraction off". This
seems to be already fixed in 3.7

I have to admit this was still tested using beta 35 but
I checked the changelog and the only photon changes FS #93
and FS #95 do not seem to relate to these issues.


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From: Christian Froeschlin
Subject: Re: Media Photons
Date: 7 Aug 2010 20:44:33
Message: <4c5dfdf1$1@news.povray.org>
Christian Froeschlin wrote:

> 3. When adding "no_reflection" to media container, the
>    reflection for the beam of light prior to hitting the photon
>    target was suppressed but reflection of the photon beam itself
>    was not suppressed (this problem occurs also in 3.6).

Ahem ... confused beams. The former was still being reflected.


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From: clipka
Subject: Re: Media Photons
Date: 8 Aug 2010 08:50:35
Message: <4c5ea81b$1@news.povray.org>
Am 08.08.2010 02:27, schrieb Christian Froeschlin:
> I played a bit with these today and encountered some issues:
>
> 1. It seems photons from cylindrical light sources are no
> longer deposited in media with 3.7
...
> I have to admit this was still tested using beta 35 but
> I checked the changelog and the only photon changes FS #93
> and FS #95 do not seem to relate to these issues.

FS#78 ("Wrong rendering of BeamTest-Scene in 3.7.beta.35a") was a photon 
issue, too, and has been fixed with beta 37. From the underlying 
problem, it pretty much fits your bill.

I presume you're using the Unix version and are still waiting for the 
beta 38 source release to be officially advertised, so it's probably 
moot to bicker about using outdated beta versions and such.


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From: clipka
Subject: Re: Media Photons
Date: 8 Aug 2010 08:58:08
Message: <4c5ea9e0@news.povray.org>
Am 08.08.2010 02:27, schrieb Christian Froeschlin:

> 2. When using spot lights it worked but with identical
> settings the beam of light was much stronger/wider in
> 3.7 than it was with 3.6

Please test again with beta 38 (a "semi-official" Unix source code 
package reflecting beta 38 is still available under the address recently 
posted by Chris); I'm not sure whether the fix for FS#78 also affected 
spot lights.


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From: clipka
Subject: Re: Media Photons
Date: 8 Aug 2010 09:02:01
Message: <4c5eaac9$1@news.povray.org>
Am 08.08.2010 14:57, schrieb clipka:
> Am 08.08.2010 02:27, schrieb Christian Froeschlin:
>
>> 2. When using spot lights it worked but with identical
>> settings the beam of light was much stronger/wider in
>> 3.7 than it was with 3.6
>
> Please test again with beta 38 (a "semi-official" Unix source code
> package reflecting beta 38 is still available under the address recently
> posted by Chris); I'm not sure whether the fix for FS#78 also affected
> spot lights.

It might also have to do with FS#93 and/or FS#95.


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From: Christian Froeschlin
Subject: Re: Media Photons
Date: 8 Aug 2010 18:39:33
Message: <4c5f3225$1@news.povray.org>
clipka wrote:

> FS#78 ("Wrong rendering of BeamTest-Scene in 3.7.beta.35a") was a photon 
> issue, too, and has been fixed with beta 37.

sorry I missed that. I now verified that the first
two problems are fixed in beta 38.

The no_reflection issue is still there. That one is
unrelated to photons, I think it basically means that
media is reflected even if the container object has
no_reflection set. I attach a test scene for that.

Interestingly, it seems to work for every pixel where
the reflected ray would not hit any other object and show
the background color instead. In those locations the media
disappears when using no_reflection.

> bicker about using outdated beta versions and such.

Sigh. The bickering would have been completely justified.

Thing is I was actually using 3.6, then I encountered the
problem with no_reflection, thought I should check if this
was still present in 3.7, and started the version I had
installed from the last time I actually used 3.7.


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