POV-Ray : Newsgroups : povray.binaries.images : Media+radiosity testing Server Time
18 Nov 2024 18:35:41 EST (-0500)
  Media+radiosity testing (Message 1 to 10 of 10)  
From: aaglo
Subject: Media+radiosity testing
Date: 7 Jul 2005 06:05:03
Message: <web.42ccfdaaecde824bb3ed5a4f0@news.povray.org>
Hi!
Since most of the things I've done previously have very little - even
nothing - to do with media and radiosity, I wanted to try them out a bit :)

So here's a very simple one, a reflective sphere BELOW chequered (sort of)
plane. "Enjoy"

My civ3-units - modelled and animated with pov-ray:
http://forums.civfanatics.com/showpost.php?p=2036938&postcount=4


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media_radiosity_test1.png


 

From: Josh
Subject: Re: Media+radiosity testing
Date: 7 Jul 2005 08:17:36
Message: <42cd1d60$1@news.povray.org>
very nice.  Can you repost it using an area light in your spot light.  I'd 
like to see that.  I might even nick it for a wallpaper at work.


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From: aaglo
Subject: Re: Media+radiosity testing
Date: 7 Jul 2005 12:20:01
Message: <web.42cd555289cf078748c045820@news.povray.org>
"Josh" <s### [at] acom> wrote:
> very nice.  Can you repost it using an area light in your spot light.  I'd
> like to see that.  I might even nick it for a wallpaper at work.

did you mean something like this? Do remember, that I'm kinda noobie with
these features :)


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From: Josh
Subject: Re: Media+radiosity testing
Date: 8 Jul 2005 11:34:37
Message: <42ce9d0d@news.povray.org>
> did you mean something like this? Do remember, that I'm kinda noobie with
> these features :)
>

Yes thats it!  It is now my wallpaper Thanks!

Whats the "ambient" setting in the pillars texture?


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From: Slime
Subject: Re: Media+radiosity testing
Date: 9 Jul 2005 01:11:35
Message: <42cf5c87@news.povray.org>
This is nice. If I may make a few suggestions:

 - Lower your anti-aliasing threshold; there are some noticeable aliasing
artifacts in the reflection and on the bottom of the sphere.
 - You can see the area light sampling bands on the floor. You can eliminate
this by bringing up the number of area light samples. Be sure to use
"adaptive 1" so that higher sampling is only done in the partially-shadowed
areas. If you're worried about this making the media render slowly, you
might consider using two separate area lights: one for the media and one for
the solid objects, by using light_groups.
 - The media itself has some banding problems. If you bring up the number of
media samples ("samples 20" for example), this could be reduced.
 - Finally, you might consider doing something to hide the abrupt ending of
the ceiling towards the edges of the scene. Maybe add walls, or make the
ceiling go farther out.

 - Slime
 [ http://www.slimeland.com/ ]


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From: Orchid XP v2
Subject: Re: Media+radiosity testing
Date: 9 Jul 2005 06:14:56
Message: <42cfa3a0$1@news.povray.org>
Now THAT looks really neat! The area light definitely helps...

(Agreed with what Slime said about turning up the various sampling 
parameters. OOC, how slow it is currently?)

As an aside... there are several places in POV-Ray where adaptive 
sampling is done. (Area lights, media, focal blur, radiosity...) I 
always thought it would be nice if there were some common syntax for all 
these different things. (Respecting of course that some of them 
inherantly have different characteristics and so different options might 
be especially applicable to only some of them.) But hey...


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From: Alain
Subject: Re: Media+radiosity testing
Date: 9 Jul 2005 13:02:13
Message: <42d00315$1@news.povray.org>
Slime nous apporta ses lumieres en ce 2005-07-09 01:11:
> This is nice. If I may make a few suggestions:
> 
>  - Lower your anti-aliasing threshold; there are some noticeable aliasing
> artifacts in the reflection and on the bottom of the sphere.
>  - You can see the area light sampling bands on the floor. You can eliminate
> this by bringing up the number of area light samples. Be sure to use
> "adaptive 1" so that higher sampling is only done in the partially-shadowed
> areas. If you're worried about this making the media render slowly, you
> might consider using two separate area lights: one for the media and one for
> the solid objects, by using light_groups.
>  - The media itself has some banding problems. If you bring up the number of
> media samples ("samples 20" for example), this could be reduced.
>  - Finally, you might consider doing something to hide the abrupt ending of
> the ceiling towards the edges of the scene. Maybe add walls, or make the
> ceiling go farther out.
> 
>  - Slime
>  [ http://www.slimeland.com/ ]
> 
> 
Using adaptive 0 may be suficient. Try an area_light aray of 17*17 or 33*33 or even
65*65. Adding 
jitter 1 may help but get less improvement when using denser arays.
I agree on more samples in the media, avoid using more intervals when using method 3
(the default) 
as it dramaticaly increase the render time. 100 samples is faster than 10 intervals!

Alain


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From: aaglo
Subject: Re: Media+radiosity testing
Date: 12 Jul 2005 05:05:01
Message: <web.42d3879189cf0787b3ed5a4f0@news.povray.org>
"Slime" <fak### [at] emailaddress> wrote:
> This is nice. If I may make a few suggestions:
>
>  - Lower your anti-aliasing threshold; there are some noticeable aliasing
> artifacts in the reflection and on the bottom of the sphere.
>  - You can see the area light sampling bands on the floor. You can eliminate
> this by bringing up the number of area light samples. Be sure to use
> "adaptive 1" so that higher sampling is only done in the partially-shadowed
> areas. If you're worried about this making the media render slowly, you
> might consider using two separate area lights: one for the media and one for
> the solid objects, by using light_groups.
>  - The media itself has some banding problems. If you bring up the number of
> media samples ("samples 20" for example), this could be reduced.
>  - Finally, you might consider doing something to hide the abrupt ending of
> the ceiling towards the edges of the scene. Maybe add walls, or make the
> ceiling go farther out.
>
>  - Slime
>  [ http://www.slimeland.com/ ]

Ok, I think I understood most of these tips :)
To the question of render time: it was about 1 h 30 mins (because of the
large number of "holes on the roof where the light comes".

I also wondered what caused the banding there. Now that's clear, thanks.

Now, here's another type of media test. Render time: 33 mins. I increased
the number of samples in the media from 15 to 90 - no more banding :) (not
that I can see).


My civ3-units - modelled and animated with pov-ray:
http://forums.civfanatics.com/showpost.php?p=2036938&postcount=4


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Attachments:
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Preview of image 'media_radiosity_test2.png'
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From: Alain
Subject: Re: Media+radiosity testing
Date: 12 Jul 2005 11:10:24
Message: <42d3dd60@news.povray.org>
aaglo nous apporta ses lumieres en ce 2005-07-12 05:04:

> 
> Ok, I think I understood most of these tips :)
> To the question of render time: it was about 1 h 30 mins (because of the
> large number of "holes on the roof where the light comes".
> 
>
If you used a difference ov a large box and several small boxes, it's slow. Some beter
solution:
- use 2 arays of long boxes in an union
- use a small diference of 2 boxes. Place them repetately to recreate your roof.
When you punch lots of holes, you get extremely bad bounding: POV Ray have to check
for all the 
diferenced small box to determine if you are on a solid or empty spot.

Alain


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From: aaglo
Subject: Re: Media+radiosity testing
Date: 12 Jul 2005 13:15:01
Message: <web.42d3fa4889cf078748c045820@news.povray.org>
Alain <ele### [at] netscapenet> wrote:
> If you used a difference ov a large box and several small boxes, it's slow. Some
beter solution:
> - use 2 arays of long boxes in an union
> - use a small diference of 2 boxes. Place them repetately to recreate your roof.
> When you punch lots of holes, you get extremely bad bounding: POV Ray have to check
for all the
> diferenced small box to determine if you are on a solid or empty spot.
>
> Alain

they weren't boxes with differences. They were cylinders.


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