I'm glad that POV 3.5 now supports radiosity interaction with double 
illumination. When MegaPOV came out with it's double_illumination 
keyword, I tried a similar experiement with no apparent effects from the 
radiosity.
This is just a simple test of this interaction involving a barn made 
from wood beams and fiberglass panels. Sun shines past a tall box 
casting partial light onto the barn, thus simulating scattered light inside.
Questions, Comments?

-- 
Samuel Benge

sbe### [at] caltelcom

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Attachments:
Download 'cornell's_barn.jpg' (38 KB)

Preview of image 'cornell's_barn.jpg'

> Comments?

Sweeeet!

-Peter

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I concur with Peter. I would never have thought of that.

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Beautiful effect! I'm gonna have to think of a scene for this :)

Corey

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Here's a second rendering of the same scene. I placed a blue light on 
the other side of the building. It passes through a plane with a fuzzy 
chain-link fence texture. Recursion_limit 2 was used with slightly lower 
radiosity settings to try and compensate for the increased rendering 
time. It took about 44 minutes to render.
Q's, C's?



-- 
Samuel Benge

sbe### [at] caltelcom

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Attachments:
Download 'cornell's_barn2.jpg' (38 KB)

Preview of image 'cornell's_barn2.jpg'

I don't know why or how you are able to continue posting images of higher
quality than most of us. These are some of the best radiosity scenes I've
seen in POV!

I'm especially impressed by the apparently small amount of time you need to
code these things. You must have a lot of experience.


Regards,
Hugo

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> This is just a simple test of this interaction involving a barn made
> from wood beams and fiberglass panels. Sun shines past a tall box
> casting partial light onto the barn, thus simulating scattered light
> inside. Questions, Comments?

Nice idea and image....

...but that's just a cheap trick, you have to use media (^&

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Corey Woodworth wrote:

> Beautiful effect!


More kudos for the POV Team :)

>I'm gonna have to think of a scene for this :)

Hmm, what about a room with a dirty or frosted window, where only part 
of the light shines through directly, and the rest is scattered? Might 
be a good effect for stained-glass windows.....

-- 
Samuel Benge

sbe### [at] caltelcom

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Wow! This one is even greater!
I'm wishing for a wallpaper which I belive would be used for a looong time
:) (or until your next pic ;-) (How about a 1024 version for my little
desktop? ;)
What hardware do you use? (fast render?)

I just have to say it again, this is great work! :)
Keep it up!

-Peter

> Here's a second rendering of the same scene. I placed a blue light on
> the other side of the building. It passes through a plane with a fuzzy
> chain-link fence texture. Recursion_limit 2 was used with slightly lower
> radiosity settings to try and compensate for the increased rendering
> time. It took about 44 minutes to render.
> Q's, C's?
>
>
>
> --
> Samuel Benge
>
> sbe### [at] caltelcom
>


----------------------------------------------------------------------------
----

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Peter Hertel wrote:

> Wow! This one is even greater!


Thanks.

> I'm wishing for a wallpaper which I belive would be used for a looong time
> :) (or until your next pic ;-) (How about a 1024 version for my little
> desktop? ;)


I think I can render one next time I go on a hike (when I'm home, the 
only things to do are done through the computer).

> What hardware do you use? (fast render?)


P4 1.6 ghz, 256 megs ram

 
> I just have to say it again, this is great work! :)
> Keep it up!

I will! Someday I'll even finish a scene!

-- 
Samuel Benge

sbe### [at] caltelcom

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Hugo wrote:

> I don't know why or how you are able to continue posting images of higher
> quality than most of us. 


Sure you do! A person just keeps learning new tricks and storing them 
away for future use. You think of an idea or feature and expand on it.

>These are some of the best radiosity scenes I've
> seen in POV!


With time you'll see more. The developers of POV(official and 
unofficial) have made radiosity faster and easier to use. More people 
are using it now, and more will be using it in the future.

> I'm especially impressed by the apparently small amount of time you need to
> code these things. You must have a lot of experience.

I've been using POV since version 3.1(about 4-5 years ago?).

-- 
Samuel Benge

sbe### [at] caltelcom

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Artis wrote:

> Nice idea and image....
> 
> ...but that's just a cheap trick, you have to use media (^&


The problem with subsurface scattering via media is that the light still 
passes through in a straight line. The light isn't made diffuse after 
exiting the object, so all you get on the other side are objects that 
have clean shadows. I can only imagine how long a render would take with 
radiosity and media coupled together! This trick actually simulates the 
effect rather accurately, as far as I can tell.
But I know you must just be kidding, because who would want another 
person to endure a month-long render? ;)


-- 
Samuel Benge

sbe### [at] caltelcom

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I absolutely AGREE!!!
Please post the source or render a 1152x864 version for my desktop...... :-P
And now for animation......!

--
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Email: apa### [at] yahoocom
ICQ: 146690431

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Samuel Benge wrote:
> 
> Hugo wrote:
> 
> > I don't know why or how you are able to continue posting images of higher
> > quality than most of us.
> 
> Sure you do! A person just keeps learning new tricks and storing them
> away for future use. You think of an idea or feature and expand on it.

Of course, having a fast machine helps. Your lamp image, for instance,
is apparently using fairly high-quality radiosity, with normal on, and
an area light to boot. I don't want to think about how long it would
take MY machine to render that.. or to do the requisite test renders to
make it look good.

-Xplo

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Samuel Benge wrote:
> 
> Artis wrote:
> 
> > Nice idea and image....
> >
> > ...but that's just a cheap trick, you have to use media (^&
> 
> The problem with subsurface scattering via media is that the light still
> passes through in a straight line. The light isn't made diffuse after
> exiting the object, so all you get on the other side are objects that
> have clean shadows. I can only imagine how long a render would take with
> radiosity and media coupled together!

My tests with MegaPOV show that radiosity and media don't seem to work
together in the way you imply. In fact, I'm not really sure how they
work together at all; maybe radiosity is affected by emission media or something?

I've no idea if this was fixed in 3.5.

-Xplo

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Samuel Benge wrote:
> 
> I'm glad that POV 3.5 now supports radiosity interaction with double
> illumination. When MegaPOV came out with it's double_illumination
> keyword, I tried a similar experiement with no apparent effects from the
> radiosity.
> This is just a simple test of this interaction involving a barn made
> from wood beams and fiberglass panels. Sun shines past a tall box
> casting partial light onto the barn, thus simulating scattered light inside.
> Questions, Comments?

Very neat, i never thought the effect could be that realistic.

One thing that i'm missing about double_illuminate is a possibility to
diminish the amount of light from the back surface, something like an
additional float parameter between 0 and 1. Of course for such scenes
where only the back side is visible there is no need for it.

Christoph

-- 
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TransSkin and more: http://www.tu-bs.de/~y0013390/  
Last updated 14 Jun. 2002 _____./\/^>_*_<^\/\.______

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> I think I can render one next time I go on a hike
That'd be very much appreciated!
>  (when I'm home, the only things to do are done through the computer).
I know how that is ;) I just finished two more than a day long renders..
Pretty scary when you start thinking of how much time you spend in front of
the computer.. And how hard it is to do something else when you're at home
:)
> I will! Someday I'll even finish a scene!
I think the pictures you posted qualify for 'scene', more than 'test'. Looks
more finished than my few finished scenes ;)

-Peter

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Xplo Eristotle wrote:

> My tests with MegaPOV show that radiosity and media don't seem to work
> together in the way you imply. In fact, I'm not really sure how they
> work together at all; maybe radiosity is affected by emission media or something?
> 
> I've no idea if this was fixed in 3.5.

 From the 3.5 docs:

"Media and Radiosity
Radiosity estimation can be affected by media. To enable this feature, 
       add media on to the radiosity{} block. The default is off"



-- 
Samuel Benge

sbe### [at] caltelcom

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Christoph Hormann wrote:

> One thing that i'm missing about double_illuminate is a possibility to
> diminish the amount of light from the back surface, something like an
> additional float parameter between 0 and 1. Of course for such scenes
> where only the back side is visible there is no need for it.


I'm with you there. Even more than that, there should be optional 
double_illuminate keywords for texture_maps so you could make, for 
example, realistic leaves. You could simulate the effect of variable 
thickness on a very minute scale without having to use impossible media 
settings.



-- 
Samuel Benge

sbe### [at] caltelcom

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Oooo... That looks photoreal in some spots...

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Tony[B] wrote:
> Oooo... That looks photoreal in some spots...

Hmm, yeah...the fourty-fifth pixel in the hundred and
nineteenth row is particularly photorealistic...;)

-- 
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Samuel Benge wrote:
>> 
>  From the 3.5 docs:
> 
> "Media and Radiosity
> Radiosity estimation can be affected by media. To enable this feature,
>        add media on to the radiosity{} block. The default is off"

IIRC, the MegaPOV docs made the same claim.

-Xplo

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