Hi,

it is able to save the precalculated patches (in memory/HD) of the
"standard"-radiosity of povray?? (like save_file/load_file of UV-POV).
This would be very useful for e.g. walkthroughts.
Can someone code this feature??  :)

Bye
  Paul

http://www.alpharay.de

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Paul Blaszczyk <3d### [at] alpharayde> wrote...
> Hi,
>
> it is able to save the precalculated patches (in memory/HD) of the
> "standard"-radiosity of povray?? (like save_file/load_file of UV-POV).
> This would be very useful for e.g. walkthroughts.
> Can someone code this feature??  :)
>

There is no 'standard' radiosity (solution found through a system of linear
equations) in POV.  The results from the indirect lighting solution that
POV-Ray uses could be saved.  However, the creation of this data is very
view-dependent, so saving and re-using it may not work well.  There may be a
way to create view-independent data, or there may be a way to re-use the
view-dependent data appropriately (generate new data when necessary and
discard old unused data).  Either of these solutions would difficult, mostly
because nobody here really knows exactly how the radiosity code in POV-Ray
works.

-Nathan

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Nathan Kopp <Nat### [at] koppcom> wrote:
: Either of these solutions would difficult, mostly
: because nobody here really knows exactly how the radiosity code in POV-Ray
: works.

  Says the one who has made povray's radiosity 10 times better...

-- 
main(i,_){for(_?--i,main(i+2,"FhhQHFIJD|FQTITFN]zRFHhhTBFHhhTBFysdB"[i]
):5;i&&_>1;printf("%s",_-70?_&1?"[]":" ":(_=0,"\n")),_/=2);} /*- Warp -*/

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Nathan Kopp wrote:
/.../
> 
> There may be a
> way to create view-independent data

With the current method? How?

Margus

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What if you saved the calculations made so far and just filled in the
blanks/added-on as things changed later on in the animation? After enough
views, it would lead to having the entire scene pre-calculated for future
re-renderings. Right?

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TonyB <ben### [at] panamaphoenixnet> wrote...
> What if you saved the calculations made so far and just filled in the
> blanks/added-on as things changed later on in the animation? After enough
> views, it would lead to having the entire scene pre-calculated for future
> re-renderings. Right?

Well, kind of.  The problem is that when the data is stored in the octree,
some 'level-of-detail' information is stored with it, which affects the way
the octree is searched.  So, if stuff is stored on a distant wall, it is
stored with a low level of detail, but if you walk up close to it, you'd
like to store more data there, if possible.

Plus, it is very important to store and read data in the octree using the
same level of detail for both store and read.  (This was a bug in the
original implementation, which led to splotchiness... sometimes it would
store with one level-of-detail, and then gather using another
level-of-detail).

-Nathan

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>So, if stuff is stored on a distant wall, it is
>stored with a low level of detail, but if you walk up close to it, you'd
>like to store more data there, if possible.

I hadn't thought of that. Good point. Darn. Looks like we might not be able
to speed this thing up. :(

Or... do you have any brilliant ideas? :)

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Is it possible to substitute the current radiosity with
hierarchical-radiosity?? This method uses patches, which could be saved.

  Paul

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Paul Blaszczyk <3d### [at] alpharayde> wrote...
> Is it possible to substitute the current radiosity with
> hierarchical-radiosity?? This method uses patches, which could be saved.
>

If such a radiosity scheme requires subdividing the scene into triangles
(which is the case with many radiosity techniques), then it could not be
easily implemented in POV-Ray, since there are many non-triangle objects in
POV.

-Nathan

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