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 CAD / Ray-Tracing / 2313
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Subject: 
Re: Radiosity example (F1 Ferrari) once again
Newsgroups: 
lugnet.cad.ray
Date: 
Thu, 30 Sep 2004 23:15:08 GMT
Viewed: 
3644 times
  
In lugnet.cad.ray, Jennifer Clark wrote:
Are you 100% sure about this? Usually the stair effect is caused by a lack
of anti aliasing. Rendering the image at a huge resolution then doing a
resize with proper resampling is more or less equivalent to enabling
anti-aliasing, but this should not be necessary - proper anti-aliasing can
use certain optimisations to make the process more efficient.

After looking closely at the forklift image, I think the stair-step effect is
happening due to POV-Ray's adaptive antialiasing algorithm.  It's much quicker
to render the image at the desired resolution with adaptive antialiasing enabled
in POV than to render really big and then shrink, but I think the part seams is
a case that the adaptive antialiasing algorithm doesn't handle well.

Most (all?) of Jan's renderings on the posted Brickshelf link don't have
antialiasing at all, so it's obvious what's causing the seam problem there.
However, the forklift done with Nico's setting definitely has antialiasing
(presumably adaptive POV antialiasing), and the seams still look bad.  I'm sure
if he did as you suggest, the problem would go away.  (I'm guessing you've made
extensive use of this technique yourself, given some of the truly spectacular
renderings you've posted.)

--Travis



Message has 1 Reply:
  Re: Radiosity example (F1 Ferrari) once again
 
"Travis Cobbs" <tcobbs@REMOVE.halibut.com> wrote in message news:I4vn98.21q3@lugnet.com... (...) there. (...) sure (...) made (...) spectacular (...) I have used the anti-aliasing quite extensively, although just by using the defaults I've never (...) (20 years ago, 4-Oct-04, to lugnet.cad.ray)

Message is in Reply To:
  Re: Radiosity example (F1 Ferrari) once again
 
"Nico Kaiser" <nico@siriux.net> wrote in message (...) Are you 100% sure about this? Usually the stair effect is caused by a lack of anti aliasing. Rendering the image at a huge resolution then doing a resize with proper resampling is more or less (...) (20 years ago, 30-Sep-04, to lugnet.cad.ray)

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