What data is saved in the first pass? Is it specific to that camera 
position, direction, up, right etc? Or does it calculate radiosity 
throughout the entire scene, even off camera?

Is the data specific to the image size, or can I do the first pass at 
800x400 and the second at 1600x800 (even if accuracy is lost) or will 
that apply the save radiosity to the (eg) upper left corner of the 
resulting render?

Cheers!
Rick Measham

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> What data is saved in the first pass? Is it specific to that camera
> position, direction, up, right etc? Or does it calculate radiosity
> throughout the entire scene, even off camera?

The radiosity is calculated only in places that are visible from the current
camera position (or through reflection/refraction). However, that data is
stored in 3D space, so you can reuse that data even if you move the camera.
In theory only the newly visible areas will be recalculated if you load the
original data. I haven't tested this.

> Is the data specific to the image size, or can I do the first pass at
> 800x400 and the second at 1600x800 (even if accuracy is lost) or will
> that apply the save radiosity to the (eg) upper left corner of the
> resulting render?

The data is not linked to the image size. It's possible that increasing the
resolution will require more radiosity calculations on top of the original
data in order to account for the greater level of detail. Again, I haven't
tested this.

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

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Slime wrote:
> The radiosity is calculated only in places that are visible from the current
> camera position (or through reflection/refraction). However, that data is
> stored in 3D space, so you can reuse that data even if you move the camera.
> In theory only the newly visible areas will be recalculated if you load the
> original data. I haven't tested this.

Has anyone else tested this? If this is the case, on the second pass, 
should I save the data as well as load it? (so that the extra data is 
added) then it might just be a case of running the second pass for most 
renders ..

Cheers!
Rick Measham

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"Rick Measham" <rickm*at%isite.net.au> wrote in message
news:43435ea2@news.povray.org...
> Slime wrote:
> > The radiosity is calculated only in places that are visible from the current
> > camera position (or through reflection/refraction). However, that data is
> > stored in 3D space, so you can reuse that data even if you move the camera.
> > In theory only the newly visible areas will be recalculated if you load the
> > original data. I haven't tested this.
>
> Has anyone else tested this? If this is the case, on the second pass,
> should I save the data as well as load it? (so that the extra data is
> added) then it might just be a case of running the second pass for most
> renders ..

Hi Rick, have you seen Tim's page regarding two-pass radiosity?

http://www.nolights.de/projects/radiosity/radiosity.html

There's a lot of great info on there which should answer many of your questions.
Tim also provides a sample scene to experiment with two-pass radiosity.

Lance.

thezone - thezone.firewave.com.au

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"Rick Measham" <rickm*at%isite.net.au> schreef in bericht
news:43435ea2@news.povray.org...
>
> Has anyone else tested this? If this is the case, on the second pass,
> should I save the data as well as load it? (so that the extra data is
> added) then it might just be a case of running the second pass for most
> renders ..
>
I had the same question for my interpretation of windows_room, and yes, my
conclusion is that you can render the second pass at a larger scale. No need
to save the data again, although... that could help for later renders
probably.

Thomas

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