Backwards antialias 2004-06-28 - By Thomas Moffat Grimes
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Hi Hans,
That's an odd problem. I'll see if I can't find an explanation of the cause
for you, for one thing.
Meantime though, the workaround - render to an image that is "anti-alias
times" bigger than you require. So if your scene is 100x100 and you want 4
times anti-alias, render to 400x400 and downsize.
I actually find this gives fractionally better rendering performance, plus
better image quality. To my eyes, the anti-alias results appear
"horizontally biased" where the pixels are smoothed from the horizontal
perspective (ie compared to pixels they are adjacent to horizontally) but
not so smoothed from the vertical perspective. I find that by making the
image x number of times larger and downsampling I can get a better result
(as well as more control thanks to using Unsharp Mask on the downsized image
to control how much sharpness is retained).
This should let you continue to produce the images you need to the quality
you need - actually it stirs up one possibility. Since the anti-alias works
in a similar way, it could well be that the larger image being generated
internally is showing the NURBS edges, as the larger image would require
greater NURBS resolution. If this is so, then rendering your image 3 times
larger should show the same artefacts you seen with 3 times anti-aliasing,
and this work around won't help - but at least we would know the problem.
This would explain why 4 is as bad as 3, but anti-aliasing of 2 is better.
Try increasing the NURBS resolution for your higher anti-aliasing renders,
as well as testing rendering to those larger images, and let us know!
Thanks!
Tom
Thomas Moffat Grimes
Marketing Communications
Caligari Corporation
mailto:thomas@(protected)
http://www.caligari.com
-- --Original Message-- --
From: hans_k [mailto:hans_k@(protected)]
Sent: Monday, June 28, 2004 10:00 AM
To: truespace@(protected)
Subject: Re: [TSML] Backwards antialias
Now I have tried this down to a single nurbs object, and found that
it is nothing spcial with my scene. Any curved nurbs object, for
example a simple cylinder gets bad edges when using antialias.
The reason I have not realized this before is that it becomes more
obvious in this scene.
- Hans
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