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Hi all!
I'm learning how to use radiosity, so I've made a small image based on the
classic Cornell Box (see below)
I've used rather high quality settings (I think), roughly based on
Radiosity_OutdoorHQ in rad_def.inc . The render took more than 24h on my
poor 750 MHz PC and though, I think there are still some radiosity artifacts
on the image (especially between the toruses; also some kind of grainy
effect).
I read the Povray docs several times, but I have a lot of difficulty
understanding how radiosity works precisely, in relation with the various
parameters. Could anybody help me find which parameter to tune to get a
better quality?
Luminous cylinders are ambient 2.8 diffuse 0
Walls are ambient 0 diffuse 0.98
Radiosity settings are:
{
brightness 1.0
count 500
error_bound 0.1
gray_threshold 0.0
low_error_factor 0.5
minimum_reuse 0.015
nearest_count 7
recursion_limit 3
adc_bailout 0.0035
max_sample -1.0
media on
normal on
always_sample 1
pretrace_start 0.08
pretrace_end 0.004
}
Thanks in advance!
Xavier
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Attachments:
Download 'mycorn2.jpg' (135 KB)
Preview of image 'mycorn2.jpg'
![mycorn2.jpg](/povray.binaries.images/attachment/%3C42111362%40news.povray.org%3E/mycorn2.jpg?ttop=441697&toff=5600&preview=1)
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> count 500
Bump this up to somewhere between 800 and 1200
> recursion_limit 3
In the scene you are using, you may be able to reduce this to 1 without any
noticeable sacrifice in quality, but it will likely reduce your render time
drastically.
- dan B hentschel
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"Xavier Manget" <REM### [at] free fr> wrote:
>
> Radiosity settings are:
> {
> brightness 1.0
> count 500
> error_bound 0.1
> gray_threshold 0.0
> low_error_factor 0.5
> minimum_reuse 0.015
> nearest_count 7
> recursion_limit 3
> adc_bailout 0.0035
> max_sample -1.0
> media on
> normal on
> always_sample 1
> pretrace_start 0.08
> pretrace_end 0.004
> }
>
I don't see any artifacts. It looks very clean to me. Unless you are using
normals and media, I would turn them off; it is slowing you down and giving
you nothing (or next to it). I am not sure I understand the max_sample
-1.0; where did you come up with that?
As far as I am concerned it looks quite good. There might be a little
unevenness in the far bottom corner/edge, and to fix that you can either
raise your count, or raise your error_bound. I think your only real problem
is the normal and media settings, which are slowing things WAY down.
-S
5TF!
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Nice, I love this one, really neat. :-))
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42111cc0@news.povray.org...
> Nice, I love this one, really neat. :-))
Thanks LB! (already posted it last week on news.zoo-logique.org, maybe you
missed it :-) )
Xavier
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Thanks, will try just now!
Xavier
web.42111850ddcdc699a3fcf12a0@news.povray.org...
>
> > count 500
>
> Bump this up to somewhere between 800 and 1200
>
> > recursion_limit 3
>
> In the scene you are using, you may be able to reduce this to 1 without
any
> noticeable sacrifice in quality, but it will likely reduce your render
time
> drastically.
>
> - dan B hentschel
>
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>
> I don't see any artifacts. It looks very clean to me. Unless you are using
> normals and media, I would turn them off; it is slowing you down and
giving
> you nothing (or next to it). I am not sure I understand the max_sample
> -1.0; where did you come up with that?
Actually, this is the default setting given by Moray, it is also the default
for Povray (I've just checked the documentation for that)
normal and media are also on by default, I will try to set them off.
> As far as I am concerned it looks quite good. There might be a little
> unevenness in the far bottom corner/edge, and to fix that you can either
> raise your count, or raise your error_bound. I think your only real
problem
> is the normal and media settings, which are slowing things WAY down.
Thanks, I will try!
Xavier
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Xavier Manget wrote:
> 42111cc0@news.povray.org...
>
>>Nice, I love this one, really neat. :-))
>
>
> Thanks LB! (already posted it last week on news.zoo-logique.org, maybe you
> missed it :-) )
>
> Xavier
So what ?! I can "officially" agree your work here too ! no ? ;-p
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Xavier Manget wrote:
> Hi all!
>
> I'm learning how to use radiosity, so I've made a small image based on the
> classic Cornell Box (see below)
>
> I've used rather high quality settings (I think), roughly based on
> Radiosity_OutdoorHQ in rad_def.inc . The render took more than 24h on my
> poor 750 MHz PC and though, I think there are still some radiosity artifacts
> on the image (especially between the toruses; also some kind of grainy
> effect).
That render time seems reasonable with such a scene and these settings.
You might try decreasing pretrace_end and low_error_count. Also
might try the 'randomize' option from MegaPOV.
Christoph
--
POV-Ray tutorials, include files, Sim-POV,
HCR-Edit and more: http://www.tu-bs.de/~y0013390/
Last updated 23 Sep. 2004 _____./\/^>_*_<^\/\.______
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cv6ohh$2ht$1@chho.imagico.de...
effect).
>
> That render time seems reasonable with such a scene and these settings.
> You might try decreasing pretrace_end and low_error_count. Also
> might try the 'randomize' option from MegaPOV.
>
> Christoph
>
Thanks for the tips Christoph,
I don't have Megapov installed (and I don't think it is compatible with
Moray)
Anyway I've re-rendered a new version with better count and error_bound
settings (took 2.5 days!), there are less artifacts now and I'm happy with
the result.
Xavier
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