POV-Ray : Newsgroups : povray.beta-test.binaries : Radiosity POV 3.6 vs. 3.7 vs. MCPov : Re: Radiosity POV 3.6 vs. 3.7 vs. MCPov Server Time
23 Feb 2024 23:05:15 EST (-0500)
  Re: Radiosity POV 3.6 vs. 3.7 vs. MCPov  
From: clipka
Date: 18 Jan 2009 16:05:00
Message: <web.497398aa516c009afb23a32b0@news.povray.org>
Ive <"ive### [at] lilysoftorg"> wrote:
> Just used one of my "never finished projects" to do a "quick" compare
> between 3.6.1 and 3.7 beta30.rad1 radiosity with moderate low setting -
> at least for this kind of scene. Lit by radiosity only, coming from a
> skysphere with a high ambient value.

Impressive scene!

> Well, look for yourself but from what I can tell the 3.7 radiosity
> lighting looks quite strange. The floor is way too bright and other
> objects like the rug on the table, the viol and the notes on the
> virginal look totally flat. Note also this has nothing to do with the
> change in gamma handling because I have always used assumed gamma of 1.0.

Comments to the pictures:

- Render times?

- The MCPov shot looks most convincing, no argument here. However, it is not
perfectly clear whether this is due to an actual superiority in quality, or
imperfections in the POV 3.6/3.7 material setup. Especially a look at the
mirror raises suspicion: While it is rather dull in the MCPov shot, it seems to
be plain 100% reflective in the POV 3.6.1 and 3.7 shots. So there must be *some*
difference in material settings.

- The 3.6.1 shot looks rather dark; I attribute this to the windows and flaws in
POV 3.6 radiosity: When gathering deep-recursion samples, POV 3.6 effectively
just traced a single level, so I guess it will not make it through the windows.
All 3rd-bounce samples will probably be pitch black, and possibly even the
2nd-bounce ones.

- The 3.7 shot indeed looks weird - but this weirdness look distinctively
familiar: "Ambient" immediately comes to mind. It looks very much like you
forgot to set all materials to "ambient 0" (or, alternatively, turn down the
"ambient_light" to something like 0.001 and multiply your sky ambient by 1000;
usually this sufficiently dims the ambient terms and saves you a lot of work.)

> Here is a link to an image I have done back in 2002 with high quality
> radiosity settings and (I guess) POV 3.5 at this time.
> http://news.povray.org/povray.binaries.images/message/<3C3da07987%40news.povray.org>

That link only leads me to the p.b.i. overview.

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