Here is a test scene for the photons and normal problem discussed in
p.a-u.  I did the 'ior 1' test and the results look quite wrong IMO.  

The first picture is with photons, the second without.  The transparent
object is of course invisible. Scene is attached too.

I remember that Nathan mentioned some problems with brightness in the 'ior
1' case in his paper, i doubt this is the same problem though.

Christoph

-- 
Christoph Hormann <chr### [at] gmxde>
IsoWood include, radiosity tutorial, TransSkin and other 
things on: http://www.schunter.etc.tu-bs.de/~chris/

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Attachments:
Download 'phot_norm_a.png' (14 KB) Download 'phot_norm_b.png' (6 KB) Download 'phot_normal.pov.txt' (2 KB)

Preview of image 'phot_norm_a.png'

Preview of image 'phot_norm_b.png'

"Christoph Hormann" <chr### [at] gmxde> wrote...
>
> Here is a test scene for the photons and normal problem discussed in
> p.a-u.  I did the 'ior 1' test and the results look quite wrong IMO.
>
> The first picture is with photons, the second without.  The transparent
> object is of course invisible. Scene is attached too.
>
> I remember that Nathan mentioned some problems with brightness in the 'ior
> 1' case in his paper, i doubt this is the same problem though.

Thanks for the scene, Chris.  This short scene will help in locating (and
hopefully solving) the problem.  Of course, it would have been more
appropriate to post it in the beta-test.binaries group.

-Nathan

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"Christoph Hormann" <chr### [at] gmxde> wrote...
>
> Here is a test scene for the photons and normal problem discussed in
> p.a-u.  I did the 'ior 1' test and the results look quite wrong IMO.
>
> The first picture is with photons, the second without.  The transparent
> object is of course invisible. Scene is attached too.
>
> I remember that Nathan mentioned some problems with brightness in the 'ior
> 1' case in his paper, i doubt this is the same problem though.

This was a bug.  It should be fixed in the next beta.

-Nathan

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Nathan Kopp wrote:
> 
> This was a bug.  It should be fixed in the next beta.
> 

I suppose this will 'break' a lot of old scenes (i know Povray 3.5 !=
megapov so it's no real problem).

Will have to try if some of my photon scenes will look more realistic with
this fix.  Do you know if reflective photons are also involved?

Christoph

-- 
Christoph Hormann <chr### [at] gmxde>
IsoWood include, radiosity tutorial, TransSkin and other 
things on: http://www.schunter.etc.tu-bs.de/~chris/

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"Christoph Hormann" <chr### [at] gmxde> wrote...
>
> Nathan Kopp wrote:
> >
> > This was a bug.  It should be fixed in the next beta.
>
> I suppose this will 'break' a lot of old scenes (i know Povray 3.5 !=
> megapov so it's no real problem).

I doubt it.  People would have expected photons to be the normal
brightness... the probably just didn't notice the problem.  Actually, post
people had photons only hitting flat (or nearly flat) objects, so it didn't
matter.

> Will have to try if some of my photon scenes will look more realistic with
> this fix.  Do you know if reflective photons are also involved?

All photons were involved.  It was a bug in the photon gathering function.

-Nathan

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Nathan Kopp wrote:
> 
> I doubt it.  People would have expected photons to be the normal
> brightness... the probably just didn't notice the problem.  Actually, post
> people had photons only hitting flat (or nearly flat) objects, so it didn't
> matter.
> 

Since it's usually hard to guess how bright photons should be, people will
usually just have accepted them being darker.

I remember photons in my water tunnel scene always seemed to be quite dim,
i will have to try it again with the fix as soon as i have time for that.

Christoph

-- 
Christoph Hormann <chr### [at] gmxde>
IsoWood include, radiosity tutorial, TransSkin and other 
things on: http://www.schunter.etc.tu-bs.de/~chris/

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