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hum... strange title but this scene is a WIP. I'm using it to test some
radiosity parameters and technics, and it will be a comprative scene in
POV and LightScape when the 3D Studio MAX model will be done.
Story:
I saw yesterday a photo in one of my brother's ebenist books of a studio
like this. I decided to do it with POV.
today, at work, while my computer was unused, I launched a render. A
graphist wanted to test the same scene in LightScape (we are using it
since a few days). So, he will do the model in MAX, and he will import
it in LightScape, I will convert it to a POV scene and we will do
tests...
My question:
I used this parameters in megapov 0.6.
pretrace_start 0.04
pretrace_end 0.01
count 300
recursion_limit 2
nearest_count 3
error_bound 0.3
I read the "Christoph's Page", I tried various values for radiosity but
I still have this dark patches in the corner of the window.
and before, with megapov 0.5, I got dark circles even with a high count
!
Thanks for helping...
David
Post a reply to this message
Attachments:
Download 'interieur.jpg' (15 KB)
Preview of image 'interieur.jpg'
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Well, the patches actually make it look a bit more real, as if the sheetrock
person or painter were a bit sloppy.
gemelli david wrote:
> hum... strange title but this scene is a WIP. I'm using it to test some
> radiosity parameters and technics, and it will be a comprative scene in
> POV and LightScape when the 3D Studio MAX model will be done.
>
> Story:
>
> I saw yesterday a photo in one of my brother's ebenist books of a studio
> like this. I decided to do it with POV.
> today, at work, while my computer was unused, I launched a render. A
> graphist wanted to test the same scene in LightScape (we are using it
> since a few days). So, he will do the model in MAX, and he will import
> it in LightScape, I will convert it to a POV scene and we will do
> tests...
>
> My question:
> I used this parameters in megapov 0.6.
> pretrace_start 0.04
> pretrace_end 0.01
> count 300
> recursion_limit 2
> nearest_count 3
> error_bound 0.3
> I read the "Christoph's Page", I tried various values for radiosity but
> I still have this dark patches in the corner of the window.
>
> and before, with megapov 0.5, I got dark circles even with a high count
> !
>
> Thanks for helping...
>
> David
>
> ------------------------------------------------------------------------
> [Image]
Post a reply to this message
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gemelli david wrote:
>
> I read the "Christoph's Page", I tried various values for radiosity but
> I still have this dark patches in the corner of the window.
>
You could try reducing error_bound, that should remove the dark spots, but this
usually leads to a less smooth overall appearance. Simultaneously increasing
count should reduce that but rendering time will exaggerate of course.
> and before, with megapov 0.5, I got dark circles even with a high count
> !
>
I didn't know radiosity changed from 0.5 to 0.6, anyone who knows ?
Christoph
--
Christoph Hormann <chr### [at] gmx de>
Homepage: http://www.schunter.etc.tu-bs.de/~chris/
Post a reply to this message
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> > and before, with megapov 0.5, I got dark circles even with a high count
> > !
> >
>
> I didn't know radiosity changed from 0.5 to 0.6, anyone who knows ?
>
> Christoph
>
I don't know if it changed but it's just to say I rendered it using two different
versions. As I downloaded the 0.6 just this morning and I didn't have time to check
what changed or not. I think it came from my parameters I modified just before
rendering the scene...
David
Post a reply to this message
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gemelli david wrote:
>
> hum... strange title but this scene is a WIP. I'm using it to test some
> radiosity parameters and technics, and it will be a comprative scene in
> POV and LightScape when the 3D Studio MAX model will be done.
>
> Story:
>
> I saw yesterday a photo in one of my brother's ebenist books of a studio
> like this. I decided to do it with POV.
> today, at work, while my computer was unused, I launched a render. A
> graphist wanted to test the same scene in LightScape (we are using it
> since a few days). So, he will do the model in MAX, and he will import
> it in LightScape, I will convert it to a POV scene and we will do
> tests...
>
> My question:
> I used this parameters in megapov 0.6.
> pretrace_start 0.04
> pretrace_end 0.01
> count 300
> recursion_limit 2
> nearest_count 3
> error_bound 0.3
> I read the "Christoph's Page", I tried various values for radiosity but
> I still have this dark patches in the corner of the window.
>
> and before, with megapov 0.5, I got dark circles even with a high count
> !
I need to write a tutorial on low-error radiosity one of these days so I
can stop typing this stuff out... >_<
One of the problems with using an error_bound of around .3 is that the
radiosity tends to be blotchy; the effect is almost as if you were
shining a light through a screen and getting a lot of holes, or
something like the multiple-shadow effect of area_lights, only more so.
I've found that increasing error_bound will make the blotches larger and
softer, and at the default error_bound of .6, they blend together well
enough as to all but disappear.. but of course, with your error_bound
this high, you won't get the neat shadows.
If you want to use these settings more or less as they are, it's crucial
that you set the pretrace_end low enough that you're getting 2-pixel
radiosity blocks (try something around .005). This will help smooth the
blotches. Also, your nearest_count is way too low; with an error of .3,
you should leave it at default. (You could even increase it to the max
of 20, but I don't think this will help.) Set low_error_factor to 1,
which should make the pretrace a little faster without hurting quality.
If you still get unacceptable dark artifacts or the smoothing still
isn't good enough, and you have a crapload of RAM, you can use a trick
to make the artifacts smaller than a pixel (which gives extremely smooth
results, if you follow me). Set your error_bound to .03, nearest_count
to 1, low_error_factor to 1, increase your count to, hmm, 500 or so for
this scene I think, and adc_bailout to 1. Pretrace_start and _end can be
set to anything you find convenient; with these settings, they have no
useful purpose other than giving you a mosaic preview and waste a lot of
time that could be used for rendering.
-Xplo
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From: Nathan Kopp
Subject: Re: radiosity inside ! (WIP, Test, Comparative, 15k)
Date: 6 Nov 2000 22:50:55
Message: <3a077c1f@news.povray.org>
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"Xplo Eristotle" <inq### [at] unforgettablecom> wrote...
> I need to write a tutorial on low-error radiosity one of these days so I
> can stop typing this stuff out... >_<
I'd love to see the results of your suggestions. It would be very
interesting to see both the low-quality smooth rendering and the
high-quality-extra-slow version.
-Nathan
Post a reply to this message
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>
> I'd love to see the results of your suggestions. It would be very
> interesting to see both the low-quality smooth rendering and the
> high-quality-extra-slow version.
>
> -Nathan
Let's go !
Params:
pretrace_start 0.04
pretrace_end 0.01
recursion_limit 2
error_bound .03
nearest_count 1
low_error_factor 1
count 500
adc_bailout 1
Render in progress !
David
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Nathan Kopp wrote:
>
> "Xplo Eristotle" <inq### [at] unforgettablecom> wrote...
> > I need to write a tutorial on low-error radiosity one of these days so I
> > can stop typing this stuff out... >_<
>
> I'd love to see the results of your suggestions. It would be very
> interesting to see both the low-quality smooth rendering and the
> high-quality-extra-slow version.
I've made a few posts here on the subject; particularly, you might want
to look for "YMFWR" and "Son of YMFWR".
-Xplo
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Hi,
gemelli david wrote:
> Params:
> pretrace_start 0.04
> pretrace_end 0.01
> recursion_limit 2
>
> error_bound .03
> nearest_count 1
> low_error_factor 1
> count 500
> adc_bailout 1
Use a recursion_limit of 3 or 4...the darker edges must be brighter and
it will look much better as at 2 :-)
Nathan:
it is right, that the maximum of recursion_limit is 6?? I've rendered a
test-scene with several values for
recursion_limit...after 6 all rendering times (also at 100 and 150) were
the same as at 6.
Paul
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Paul Blaszczyk wrote:
>
> Hi,
>
> gemelli david wrote:
> > Params:
> > pretrace_start 0.04
> > pretrace_end 0.01
> > recursion_limit 2
> >
> > error_bound .03
> > nearest_count 1
> > low_error_factor 1
> > count 500
> > adc_bailout 1
>
> Use a recursion_limit of 3 or 4...the darker edges must be brighter and
> it will look much better as at 2 :-)
I'm not so sure about that.. in a number of my tests, the differences
between 2 and higher levels were noticible, but not especially significant.
> Nathan:
> it is right, that the maximum of recursion_limit is 6?? I've rendered a
> test-scene with several values for
> recursion_limit...after 6 all rendering times (also at 100 and 150) were
> the same as at 6.
I would think that the amount of "light" given off from each bounce
would get smaller and smaller.. perhaps, at that high of a recursion
level, the extra bounces are contributing so little to the scene that
they don't show up at all.
-Xplo
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