POV-Ray : Newsgroups : povray.macintosh : Large panoramic images have a completely black sector Server Time: 26 Jun 2019 19:52:53 GMT
  Large panoramic images have a completely black sector (Message 1 to 2 of 2)  
From: Franz von Dardel
Subject: Large panoramic images have a completely black sector
Date: 28 Feb 2014 18:20:00
Message: <web.5310d076cf27caf2c812f8d90@news.povray.org>
I am producing cylindrical and spherical panoramic images, the size being 5000 x
1250 and 4000 x 2000 respectively, PNG format. Using POVRay 3.7 unofficial, with
radiosity. A very small part of the image is very memory-intensive; it contains
bottles of white wine in clear glass bottles.

Rendering takes from 1 to 5 hours depending on the settings: with
max_trace_level 20, it is very slow, so I reduced it to 10 or 12. I also updated
to the Feb 2014 update in the hope that the problem was solved.

The curious thing is that within POVRay, the image is complete, but when I want
to rename it or open it with another software (Photoshop or GraphicConverter), a
large portion of the image is completely black.

I have posted the images here after downsizing them:
http://dardel.info/imagesPOV/Keller_Cyl1.png (2000 x 500, i.e. 40% of the
original)
and
http://dardel.info/imagesPOV/Keller_Sph1.png (1000 x 500, 25% of the original)

Note that the upper left corner of the black polygon is the same in both images;
it starts in the memory-intensive area.

I was able to obtain a workable version of the cylindrical image after reducing
max_trace_level from 20 to 10 (which shortened the rendering time from more than
4 to about 1 hour, but I increased it again to 12 for the spherical image, and
this produced again a black polygon.

Once again, when I see the pict in the rendering window of POVRay, I see nothing
wrong, but I am not able to recover that image.

In smaller sizes, the problem doesn't seem to occur. Also, with other scenes
that don't have the bottles of white wine, there is no problem when rendering at
the same large size.

What may be wrong?

P.S. MacBook Pro, processor 2.2 GHz, memory 4 GB, OS 10.7.5


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From: Franz von Dardel
Subject: Re: Large panoramic images have a completely black sector
Date: 28 Feb 2014 21:35:00
Message: <web.531100b5fdf62525c812f8d90@news.povray.org>
Last minute: by lowering max_trace_level to 10 instead of 12, the problem
disappears...


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