> Your results have come out much better than mine did though - it was the first
> time I used photons, so I probably didn't understand what I was doing
> properly...

   Are you supposing that I know what I'm doing with photons? ...then you 
are wrong! ;)

   Seriously, I only managed to get them right by using two passes, because 
on "direct" usage I was getting only the photons but not the original light 
source... by loading the photons on a second pass I got both the light and 
the photons.

> My plan had a "part two" to it (which I also didn't manage to do properly) - I
> wanted to render the light and fixture, without any other scene elements, to a
> full spherical camera, and use that as the transparency map for the light in a
> real scene (possibly with the fixture modified with no_shadow). If you get what
> I mean...
> 
> It's still on my list of things to experiment with, but perhaps as you are
> having far more success than I ever did, it might be something you would find
> interesting?

   Very interesting idea... and I didn't think of it! But now you ruined my 
Saturday plans... I'm not able to resist the temptation!

   How will you proceed? ...perhaps projecting it into a sphere?

--
Jaime

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Jaime Vives Piqueres wrote:
> Hi again:
> 
>     After Edouard mentioned IES light data files, I tried an experiment I
> envisioned sometime ago: creating a realistic spot fixture and let it
> reflect and refract some photons. The tests with just one spot seemed to
> work nicely, but when I integrated it on the hotel scene with the same
> photon spacing, the results don't look so great...
> 
> -- 
> Jaime
> 

Just to make sure I do understand it right: you did *not* actually use 
IES files, you 'just' did model a realistic spotlight with a refracting 
mirror?

If my memory does serve me well there was (maybe a few years ago) a post 
by someone who did in fact use IES files within POV-Ray. But while I'm 
thinking about it, I have no idea how this could be achieved.

-Ive

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refracting mirror?

err, what I wanted to say was reflecting mirror and/or refracting glass 
cover.

-Ive

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> 
> refracting mirror?
> 
> err, what I wanted to say was reflecting mirror and/or refracting glass 
> cover.
> 

   Yes, that was the idea: I modeled with Wings3D a simple reflector with a
simple cover glass. I put a light inside and adjusted the photons to reflect
only on the reflector, and to refract only on the glass (otherwise I was
getting spotty results). It works decently with just one spot, but for a
bunch of them you need a lot of patience.

   About the IES files, as I mentioned before, yes, I also remember someone
doing a patch or something to use them with POV-Ray... perhaps it was the
custom POV-Ray version from Dialux?

--
Jaime

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> My plan had a "part two" to it (which I also didn't manage to do 
> properly) - I wanted to render the light and fixture, without any other 
> scene elements, to a full spherical camera, and use that as the 
> transparency map for the light in a real scene (possibly with the fixture
>  modified with no_shadow). If you get what I mean...
> 
> It's still on my list of things to experiment with, but perhaps as you 
> are having far more success than I ever did, it might be something you 
> would find interesting?

   Well... the experiment worked great and fast, but has a BIG limitation:
you cannot use area lights with it, because the "fake photons" effect
disappears (logically) due to the soft shadows... &%#$!!! :(

   Any ideas? ... I cannot think of anything that will overcome this problem.

--
Jaime

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Jaime Vives Piqueres <jai### [at] ignoranciaorg> wrote:
> Hi again:
>
>      After Edouard mentioned IES light data files, I tried an experiment I
> envisioned sometime ago: creating a realistic spot fixture and let it
> reflect and refract some photons. The tests with just one spot seemed to
> work nicely, but when I integrated it on the hotel scene with the same
> photon spacing, the results don't look so great...

Oops.  Is that fourteen backwards?  Otherwise very nice.

 - Ricky

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Jaime Vives Piqueres <jai### [at] ignoranciaorg> wrote:

> > My plan had a "part two" to it (which I also didn't manage to do
> > properly) - I wanted to render the light and fixture, without any other
> > scene elements, to a full spherical camera, and use that as the
> > transparency map for the light in a real scene (possibly with the fixture
> >  modified with no_shadow). If you get what I mean...
> >
> > It's still on my list of things to experiment with, but perhaps as you
> > are having far more success than I ever did, it might be something you
> > would find interesting?
>
>    Well... the experiment worked great and fast, but has a BIG limitation:
> you cannot use area lights with it, because the "fake photons" effect
> disappears (logically) due to the soft shadows... &%#$!!! :(
>
>    Any ideas? ... I cannot think of anything that will overcome this problem.

Ahh, I see the flaw. The "shadow map" from the light and fitting is an
approximation, but from your experiment it sounds like it's not a close enough
one to actual photons...

Hmm, perhaps a no_area_light object modifier added to the SDL? That would
probably be useful in general to be honest.

I can't think of a multiple light solution that would work, and even if there
was one it wouldn't be a general solution to a scene.

Sorry my idea wasn't a winner in the end!

> Jaime

Cheers,
Edouard.

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> Ahh, I see the flaw. The "shadow map" from the light and fitting is an 
> approximation, but from your experiment it sounds like it's not a close 
> enough one to actual photons...

   No, in fact it is very close to the photons effect, in some aspects better
looking, although not correct, of course. See attached pics...

> Hmm, perhaps a no_area_light object modifier added to the SDL? That would
>  probably be useful in general to be honest.

   Yes, I think that would be the only solution: the sphere with the
"photon map" could be flagged as "no_area_light". But I cannot think of any
other situation where it will be useful such a modifier...

> I can't think of a multiple light solution that would work, and even if 
> there was one it wouldn't be a general solution to a scene.

   Well, lets wait... we all know POV-Ray unexplored possibilities are
endless, and perhaps there is already a clever way to do it, waiting for
someone to discover it.

> Sorry my idea wasn't a winner in the end!

   It was a very good idea, and just in case, I will archive it under my
/stalled folder...


--
Jaime

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Attachments:
Download 'fakespot_map.jpg' (22 KB) Download 'fakespot_test.jpg' (22 KB)

Preview of image 'fakespot_map.jpg'

Preview of image 'fakespot_test.jpg'

> Oops.  Is that fourteen backwards?  Otherwise very nice.

   Oops, indeed... Thanks!

--
Jaime

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Jaime Vives Piqueres <jai### [at] ignoranciaorg> wrote:
> I was practicing with Chief Architect, and did this hotel corridor... it was
> so boring that I decided to have some fun adding some story to it.

Am I right that the bit about the mirrored 14 involves the janitor?

--
jussi

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