Hi All

This is my first article in POV news and first of all sorry for my english
mistakes.
I didn't check all news entries about my problem (may be there is answer for
my problem in news).
So the problem:
If I use RADIOSITY with glass material I got always (smaller or biger) gray
patches.
If I don't use glass result is correct.
What do I wrong?
In attachement I used sample from original POV-ray and I've changed two
objects material to glass.
Red circles show differences.(I cloud post image into povray.binaries.images
with same subject)

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Legio wrote:
> Hi All
> 
> This is my first article in POV news and first of all sorry for my english
> mistakes.
> I didn't check all news entries about my problem (may be there is answer for
> my problem in news).
> So the problem:
> If I use RADIOSITY with glass material I got always (smaller or biger) gray
> patches.
> If I don't use glass result is correct.
> What do I wrong?
> In attachement I used sample from original POV-ray and I've changed two
> objects material to glass.
> Red circles show differences.(I cloud post image into povray.binaries.images
> with same subject)
> 
> 
I'm not completely sure since I never used glass objects with radiosity.
But the black sparkle to be seen at the bottom of the glass object
seem to come from the underlying plane *touching* the bottom of the 
glass (coplanar surfaces error). Lifting the glass object a tiny bit 
(like 1% or less) may help to *disconnect* both objects.

Sebastian

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"Sebastian H." <van### [at] gmxde> wrote:
> Legio wrote:
> > Hi All
> >
> > This is my first article in POV news and first of all sorry for my english
................
> >
> >
> I'm not completely sure since I never used glass objects with radiosity.
> But the black sparkle to be seen at the bottom of the glass object
> seem to come from the underlying plane *touching* the bottom of the
> glass (coplanar surfaces error). Lifting the glass object a tiny bit
> (like 1% or less) may help to *disconnect* both objects.
>
> Sebastian

Thank you Sebastian for your answer.
I've tried and got same result just sparkles appeared another place.
Could it be general error of POV engine or wrong set in RADIOSITY section?
(I used "best" RADIOSITY set from help of POV-ray)

Thx
Legio

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Legio wrote:
> "Sebastian H." <van### [at] gmxde> wrote:
> 
>>Legio wrote:
>>
>>>Hi All
>>>
>>>This is my first article in POV news and first of all sorry for my english
> 
> .................
> 
>>>
>>I'm not completely sure since I never used glass objects with radiosity.
>>But the black sparkle to be seen at the bottom of the glass object
>>seem to come from the underlying plane *touching* the bottom of the
>>glass (coplanar surfaces error). Lifting the glass object a tiny bit
>>(like 1% or less) may help to *disconnect* both objects.
>>
>>Sebastian
> 
> 
> Thank you Sebastian for your answer.
> I've tried and got same result just sparkles appeared another place.
> Could it be general error of POV engine or wrong set in RADIOSITY section?
> (I used "best" RADIOSITY set from help of POV-ray)
> 

What radiosity settings are good differ a lot from scene to scene.
It's always a bit trial and error but I'm far from expert here
I just did some example cases.
You could try to increase the count (maximum 1600 iirc) or increase
the error_bound if the image is too grainy.
The latter would reduces the light sample resolution which probably
give a more blurish look but it may help to get rid of the black spots
(I hope I understood this correct). Also increasing nearest_count may
help.

Good luck,
Sebastian

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"Sebastian H." <van### [at] gmxde> wrote:
............
> (I hope I understood this correct). Also increasing nearest_count may
> help.
>
> Good luck,
> Sebastian

Thanx fo all.

Sebastian you've shown that I was not unwavering enough:)
I could get fine result with modified RADIOSITY set.

Legio

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