Am I mistaken that there is a difference? I started a print quality render
on a work computer before leaving this weekend. The image is not really
slow, but there are a lot of thin lines, so I tried the settings:

+A0.0001;  +AM1;  +R9;

Assuming that this would supersample any pixels with a visual difference. I
waited to see the first lines at the top of the image, and they looked bad.
They weren't thin enough to be missed, they just looked pixelated. Changing
to:

+A0;  +AM1;  +R9;

Supersampled even the white background, but the lines looked great. Am I
misunderstanding something about command line options?

 -Shay

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Shay wrote:
> Am I mistaken that there is a difference? I started a print quality render
> on a work computer before leaving this weekend. The image is not really
> slow, but there are a lot of thin lines, so I tried the settings:
> 
> +A0.0001;  +AM1;  +R9;
> 
> Assuming that this would supersample any pixels with a visual difference. I
> waited to see the first lines at the top of the image, and they looked bad.
> They weren't thin enough to be missed, they just looked pixelated. Changing
> to:
> 
> +A0;  +AM1;  +R9;
> 
> Supersampled even the white background, but the lines looked great. Am I
> misunderstanding something about command line options?

This is correct, '+a0.0' will supersample all pixels so it will be 
really slow but you will also get good results of course.  For better 
performance it is often a good idea to use adaptive antialiasing and a 
threshold slightly above 0.  To avoid persistent artefacts you can try a 
fairly strong jitter.

Christoph

-- 
POV-Ray tutorials, include files, Sim-POV,
HCR-Edit and more: http://www.tu-bs.de/~y0013390/
Last updated 21 Mar. 2004 _____./\/^>_*_<^\/\.______

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In article <408bd27b@news.povray.org>, Shay <sah### [at] simcopartscom> wrote:

> Supersampled even the white background, but the lines looked great. Am I
> misunderstanding something about command line options?

+A0 will supersample even when there is no difference in the initial 
samples. +A0.0001 will only supersample if there is a difference greater 
than the given threshold, and it's those zero-difference pixels that are 
causing a problem.
It might be useful to have some way of forcing POV to supersample to 
some level before going into adaptive mode, making it more likely to 
find these pixels while wasting less time on fully supersampling pixels 
which really don't need it.

-- 
Christopher James Huff <cja### [at] earthlinknet>
http://home.earthlink.net/~cjameshuff/
POV-Ray TAG: <chr### [at] tagpovrayorg>
http://tag.povray.org/

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"Christopher James Huff" <cja### [at] earthlinknet> wrote in message
news:cjameshuff-AAA08F.12251925042004@news.povray.org...
|
| +A0 will supersample even when there is no difference in the
| initial samples. +A0.0001 will only supersample if there is a
| difference greater than the given threshold, and it's those
| zero-difference pixels that are causing a problem.

Of course! I've got to admit that was a pretty brain-dead question.
Makes perfect sense now that I see it in print. Looking now, it's easy
to see that the AA on the right side of a thin line looks better than
that on the left.

| It might be useful to have some way of forcing POV to
| supersample to some level before going into adaptive
| mode, making it more likely to find these pixels while
| wasting less time on fully supersampling pixels
| which really don't need it.

Absolutely. I remember someone writing a patch like this once. Each ray
would check the center and the corners of each pixel before deciding
whether to super-sample.

Thanks, guys.
 -Shay

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What about using focal blur with variance 0 and confidence 0.99999999999
instead?

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Apache wrote:
> What about using focal blur with variance 0 and confidence
> 0.99999999999 instead?

Or what about just rendering at 2x the resolution with "normal" AA settings?

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