"Christoph Hormann" <Chr### [at] schunteretctu-bsde> wrote in
message news:39B4F61C.19135F25@schunter.etc.tu-bs.de...
|
| Recursion limit above 1 is not necessary in many situations, but there has
to be
| something wrong IMO, because you should get at least a strong bluish touch
| because of the sky in every radiosity version.  It could help if you would
| explain the changes made between the radiosity/no radiosity version.

Isn't much changed, well that's a white lie.  The ambient is dropped to near
zero for the radiosity images but that's a well known fact (I just tend to
leave it non-zero though, very low).  And the lighting is changed somewhat
as well as the sphere (not sky_sphere) for the sky because of the drastic
differences when ambient is dropped.  In other words, ambient and diffuse
for the sky is .6, .6  in radiosity and .67, .33 without.
The radiosity itself is done like so:

#if (Use_MP & Rad = yes)
 ambient_light <.1,.05,.025>
 ini_option "+qr"
 radiosity {
pretrace_start .08
pretrace_end .01
         media off
         normal on
         count 100 // or 50 // may be too low
         nearest_count 5
         error_bound .321
         low_error_factor .321
         gray_threshold .2
         recursion_limit 2 // or 1
         minimum_reuse .0167
        // brightness 1.333
          }
#else
 ambient_light <1,1.025,1.05>*.75
#end
}

Hope that tells you what you were wanting to know.

Bob

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Bob Hughes wrote:
> 
> #if (Use_MP & Rad = yes)
>  ambient_light <.1,.05,.025>
[...]
> #else
>  ambient_light <1,1.025,1.05>*.75
> #end

That's probably the reason for the missing additional blue in the radiosity
version.  

For the rest: I think the balconies look much better in the radiosity version,
because it generates some structures in the shadows, while the conventional
lighting only shows the plain ambient. 

Christoph 

--
Christoph Hormann <chr### [at] gmxde>
Homepage: http://www.schunter.etc.tu-bs.de/~chris/

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I don't know about the radiosity side of things, but the buildings
have really come along. 

-- 
Cheers
Steve              email mailto:ste### [at] zeroppsuklinuxnet

%HAV-A-NICEDAY Error not enough coffee  0 pps. 

web http://www.zeropps.uklinux.net/

or  http://start.at/zero-pps

  4:33pm  up 14 days, 20:51,  2 users,  load average: 1.00, 1.00, 1.00

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Bob, what happens if you use "ambient_light 0" for both/all three?

Grim

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Doh! Nevermind. I went back and read everything you wrote.

I think what is going on is you have adjusted the scene for similarity (re:
rad/no rad). MP rad really kicks in when you have no ambient components.
Sky_spheres, of course, influence the scene none-the-less (in my experiments
anyway), but everything else should be defined as ambient 0, unless you want
them to glow/radiate. Adding ambient_light really messes with things.

You are, of course, free to use artistic interpretation at your own whims!
:) I'm always playing with such things.

Grim

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Bob Hughes wrote:
> 
> Isn't much changed, well that's a white lie.  The ambient is dropped to near
> zero for the radiosity images but that's a well known fact (I just tend to
> leave it non-zero though, very low).  And the lighting is changed somewhat
> as well as the sphere (not sky_sphere) for the sky because of the drastic
> differences when ambient is dropped.  In other words, ambient and diffuse
> for the sky is .6, .6  in radiosity and .67, .33 without.

Set the sky ambient to 1 and diffuse to 0.

> #if (Use_MP & Rad = yes)
>  ambient_light <.1,.05,.025>

Yeah, I'd kill that ambient. If you're doing this right, you really
shouldn't need it, it'll just wash out whatever deep shadows you DO end
up with.

> pretrace_start .08
> pretrace_end .01
>          media off
>          normal on
>          count 100 // or 50 // may be too low
>          nearest_count 5
>          error_bound .321
>          low_error_factor .321
>          gray_threshold .2
>          recursion_limit 2 // or 1
>          minimum_reuse .0167
>         // brightness 1.333

Unless hyper-accurate shadowing is a necessity, and I don't see why it
would be for this scene, error_bound will be just fine between 0.6 and
1. Count 50 is plenty; a high count is best when you have small, bright
objects, or a very "noisy" scene, but you have a relatively simple one
with an entire lit hemisphere. You could even go down to 30. Set the
low_error_factor to 1, you're not going to need it (in my testing, it's
pretty useless). Recursion_limit 1 is plenty, I wouldn't mess with the
minimum_reuse, and brightness could go as high as 1.667 or so.

You could even set pretrace_start to .01 if you want to shave an extra
several seconds off; I haven't found that multiple passes help, provided
that the one pass you DO use is fine enough.

Try that and see how it goes. :)

-Xplo

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"Steve" <ste### [at] zeroppsuklinuxnet> wrote in message
news:slr### [at] zero-ppslocaldomain...
| I don't know about the radiosity side of things, but the buildings
| have really come along.

Thanks Steve.  And just when I'm ready to move on.

Bob

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"Xplo Eristotle" <inq### [at] unforgettablecom> wrote in message
news:39B5787A.641CC3B5@unforgettable.com...
|
| Set the sky ambient to 1 and diffuse to 0.

Well, you are saying the opposite there from my experiences with the MegaPov
kind.  Perhaps you are talking of official POV-Ray though.

| >          count 100 // or 50 // may be too low
|
| Unless hyper-accurate shadowing is a necessity, and I don't see why it
| would be for this scene, error_bound will be just fine between 0.6 and
| 1. Count 50 is plenty; a high count is best when you have small, bright
| objects, or a very "noisy" scene, but you have a relatively simple one
| with an entire lit hemisphere. You could even go down to 30. Set the
| low_error_factor to 1, you're not going to need it (in my testing, it's
| pretty useless). Recursion_limit 1 is plenty, I wouldn't mess with the
| minimum_reuse, and brightness could go as high as 1.667 or so.
|
| You could even set pretrace_start to .01 if you want to shave an extra
| several seconds off; I haven't found that multiple passes help, provided
| that the one pass you DO use is fine enough.
|
| Try that and see how it goes. :)

Yep, I'll check another render out using your advice.  What I did was to use
the recent radiosity settings Mike Hough and others had been using for those
smoothed shadowed hemispherically lit Arnold-like things, figuring if it was
good enough for that....
The main point I wanted to make is how a radiosity rendering could
potentially be worthless compared to a much speedier rendering.  I mean 16
times slower than a comparable radiosity render (5.25 hours vs. 1/3 hour!)
with recursion at 1 is no doubt all in vain.  It's sure to vary greatly
scene to scene but I think people should be made aware.  The general rule of
small test renders always applies.

Thanks for the helpful hints.

Bob

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"GrimDude" <gri### [at] netzerocom> wrote in message
news:39b55893@news.povray.org...
| Doh! Nevermind. I went back and read everything you wrote.

The reason for the sky not being a sky_sphere is for when the media is used,
that's where the needed finish comes into play otherwise I wouldn't be using
a regular sphere at all.

| I think what is going on is you have adjusted the scene for similarity
(re:
| rad/no rad). MP rad really kicks in when you have no ambient components.
| Sky_spheres, of course, influence the scene none-the-less (in my
experiments
| anyway), but everything else should be defined as ambient 0, unless you
want
| them to glow/radiate. Adding ambient_light really messes with things.

You guessed that right.  It's all so the two look about the same, excepting
for what I was trying to get the radiosity to enhance.

| You are, of course, free to use artistic interpretation at your own whims!
| :) I'm always playing with such things.

No end in sight to that here also.

Bob

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Bob Hughes wrote:
> 
> "Xplo Eristotle" <inq### [at] unforgettablecom> wrote in message
> news:39B5787A.641CC3B5@unforgettable.com...
> |
> | Set the sky ambient to 1 and diffuse to 0.
> 
> Well, you are saying the opposite there from my experiences with the MegaPov
> kind.  Perhaps you are talking of official POV-Ray though.

Nope, I'm talking about MegaPOV. With those settings, the sky SHOULD
give off radiosity but not receive any, which is what it ought to do.
(In real life, the sky probably DOES pick up some ground radiosity, but
I doubt it makes a lot of difference.)

> Yep, I'll check another render out using your advice.  What I did was to use
> the recent radiosity settings Mike Hough and others had been using for those
> smoothed shadowed hemispherically lit Arnold-like things, figuring if it was
> good enough for that....

I posted the first one of those. ;)

> The main point I wanted to make is how a radiosity rendering could
> potentially be worthless compared to a much speedier rendering.

Well, that's true of almost anything: antialiasing, photons, area_light
settings, isosurface accuracy, et al.

-Xplo

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