POV-Ray : Newsgroups : povray.binaries.images : Atmospheric Media (again) Server Time
5 Nov 2024 14:23:39 EST (-0500)
  Atmospheric Media (again) (Message 1 to 9 of 9)  
From: Bryan Valencia
Subject: Atmospheric Media (again)
Date: 18 Jul 2005 10:43:34
Message: <42dbc016@news.povray.org>
I think I've improved this quite a bit.  I have abandoned the 'rain' idea as
it's out of the scope of this project.
Enjoy!


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From: roelof
Subject: Re: Atmospheric Media (again)
Date: 18 Jul 2005 11:45:01
Message: <web.42dbce01aa80b0b2a8399d8d0@news.povray.org>
"Bryan Valencia" <pov### [at] spamgourmetcom> wrote:
> I think I've improved this quite a bit.  I have abandoned the 'rain' idea as
> it's out of the scope of this project.
> Enjoy!

hey,
it looks nice whit the media, but the textures are a bit the same. you
should try some different textures for the pipes and pilars to get some
contrast.

roelof,

http://jwstolk.xs4all.nl/roelof/


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From: Bob Hughes
Subject: Re: Atmospheric Media (again)
Date: 18 Jul 2005 13:16:40
Message: <42dbe3f8$1@news.povray.org>
Excuse me for coming in late on this Bryan. I saw one or two previous 
renderings before and I forget now what you're ultimate goal might be 
about-- if there was any, that is.

Well, I'm going to say something about this now. It looks to me like there 
needs to be greater emphasis on the light and media interaction. I could be 
way off on what you're really doing, but if I were you I would probably 
increase the brightness of the lighting coming from both the grid and walls. 
And in the process make the media brighter, too.

There probably should be very dark, nearly black, regions where the light is 
either in shadow or very weakly lit. The image seems to suffer the age-old 
affliction of being washed out. At least it does so here on my LCD screen so 
it could be different if seen elsewhere or just a matter of personal 
perception of what looks right. Even with the multiple light sources I'd 
still expect to see black areas along the pipes for example.

On closer inspection I see that beyond the hatchway door it looks dimly lit 
but with the same light as that which comes from above. Maybe you have a 
wall back there but it looks wrong, like you're media might be filling it up 
way behind there. Just making guesses outloud.

Also, area_light would probably be a good idea since those wall lights 
shouldn't be like point sources.

Bob Hughes


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From: Jim Charter
Subject: Re: Atmospheric Media (again)
Date: 18 Jul 2005 13:43:54
Message: <42dbea5a$1@news.povray.org>
Bob Hughes wrote:
What Bob said and I would also encourage you to play with fade_distance 
fade_power on the interior wall lights


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From: Bryan Valencia
Subject: Re: Atmospheric Media (again)
Date: 18 Jul 2005 14:19:47
Message: <42dbf2c3$1@news.povray.org>
Thanks for all your suggestions.

The point of the project was to create a scene with visible light streaming
into the scene (scattering media example).  I wanted to create a kind of
gloomy place where there was sunshine outside, but you can't get there LOL.

On top is not an area-light, it's actually intednded to be sunlight.  It was
really dark before I added the interior lights.  I suppose I could re-render
without them and have the radiosity try to pick up more of the detail at a
higher quality setting.


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From: Bob Hughes
Subject: Re: Atmospheric Media (again)
Date: 18 Jul 2005 14:44:59
Message: <42dbf8ab$1@news.povray.org>
"Bryan Valencia" <pov### [at] spamgourmetcom> wrote in message 
news:42dbf2c3$1@news.povray.org...
>
> The point of the project was to create a scene with visible light 
> streaming
> into the scene (scattering media example).  I wanted to create a kind of
> gloomy place where there was sunshine outside, but you can't get there 
> LOL.

Ah yes, okay, so it isn't intended to be focused on being a wet sewer with 
emphasis on the surface texturing. I thought maybe your message subject line 
could just be a part or step in the direction you were headed with this.

> On top is not an area-light, it's actually intednded to be sunlight.  It 
> was
> really dark before I added the interior lights.  I suppose I could 
> re-render
> without them and have the radiosity try to pick up more of the detail at a
> higher quality setting.

Jim suggested light fading so I'll say media attenuation (along with 
absorption) might be something to do with it, too, if not already tried.

I was trying to recreate a quick version of your scene here and found myself 
using unconventional numbers for the lights and radiosity (with 
ambient_light 0). But then many people do that, so who's to say what is 
conventional?

Anyway... I couldn't get good dark shadowy places unless I used radiosity 
brightness 0.5, assumed_gamma 1.5 and lights with colors of rgb 3 (sun) and 
rgb 2 (bulbs), the inside lights use fade_distance 0.25 fade_power 2 and the 
tunnel is 2 units across and 10 units long. Not always as easy to do 
something as it might seem at first. I probably got way off track.
; )
Bob


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From: Bryan Valencia
Subject: Re: Atmospheric Media (again)
Date: 18 Jul 2005 14:52:49
Message: <42dbfa81@news.povray.org>
I posted the scene at "povray.text.scene-files".  Knock yourself out :)


"Bob Hughes" <bob### [at] charternet> wrote in message
news:42dbf8ab$1@news.povray.org...
> "Bryan Valencia" <pov### [at] spamgourmetcom> wrote in message
> news:42dbf2c3$1@news.povray.org...
> I was trying to recreate a quick version of your scene here...


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From: Bob Hughes
Subject: Re: Atmospheric Media (again)
Date: 18 Jul 2005 16:16:56
Message: <42dc0e38$1@news.povray.org>
"Bryan Valencia" <pov### [at] spamgourmetcom> wrote in message 
news:42dbfa81@news.povray.org...
>I posted the scene at "povray.text.scene-files".  Knock yourself out :)

Thanks Bryan.

Couple things I noticed:

"intervals 10". The default media method adjusts intervals itself, unless 
you really want to change it anyhow. Could be slowing the render down.

"assumed_gamma 0.8". That would explain the washed out appearance since 1.0 
is usually recommended. Although, that's not much different.

I shortened the fade_distance to half, or 1.5, then raised the color up to 
3.0 for those wall lights and the tunnel is much darker; also with the 
assumed_gamma at 1. Raised the media scattering color up to 0.0025, as well, 
so it's smokier. Smokey might not be your idea for this scene but it sure is 
more visible.

The main thing is apparently those lights, though. Really makes a difference 
changing those.

You might find it necessary to increase the media samples some to prevent 
choppiness of the media, especially since it's going through that grid.

Bob


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From: Joanne Simpson
Subject: Re: Atmospheric Media (again)
Date: 18 Jul 2005 21:05:01
Message: <web.42dc5117aa80b0b2500142a10@news.povray.org>
>On top is not an area-light, it's actually intednded to be sunlight.

I usually use an area light for sunlight (4x4) is good enough. Because if
you look at the shadows cast by bright sunlight, they actually have diffuse
edges. A hard edge looks unnatural. (looking at sunlight on my desk as I
type).
Joanne
http://www.onewhiteraven.com


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