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Margus Ramst <mar### [at] peak edu ee> wrote:
: I.e. how is a "truly infinite" quadric cylinder better than a regular cylinder
: scaled so long that POV considers it infinite?
There might be some accuracy problems if you scale an object too much
in one direction (remember that it's actually the ray that is
inverse-transformed; scaling the cylinder extremely long in one direction
means actually that you are scaling the rays inside an extremely narrow
area; might be so narrow that you get accuracy problems).
Also specifying too big endpoints for the cylinder might cause accuracy
problems.
These accuracy problems can be specially true if you are using an
isosurface. The bigger the contained_by object, the less accurate the
isosurface.
--
main(i,_){for(_?--i,main(i+2,"FhhQHFIJD|FQTITFN]zRFHhhTBFHhhTBFysdB"[i]
):_;i&&_>1;printf("%s",_-70?_&1?"[]":" ":(_=0,"\n")),_/=2);} /*- Warp -*/
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> These accuracy problems can be specially true if you are using an
> isosurface. The bigger the contained_by object, the less accurate the
> isosurface.
Really, this should probably be relative to the camera... ie if the camera is at
2 nanounits of the isosurface that has size of (1000, 1000, 1000)... that
should also give the problems you mentionned, I think!... This is probably
because povray uses a maximum of 32 bits or 64 to determine a number and if you
zoom too much you will overload that 32-64 bits number and then will have a few
precision bugs...
Is this true, I never worked with isosurfaces...
--
+-------------------------+----------------------------------+
| Simon Lemieux | Website : http://www.666Mhz.net |
| Email : Sin### [at] 666Mhz net | POV-Ray, OpenGL, C++ and more... |
+-------------------------+----------------------------------+
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On Thu, 16 Nov 2000 03:44:40 +0200, Margus Ramst <mar### [at] peak edu ee>
wrote:
>Peter Popov wrote:
>>
>> That's exactly what I had in mind. With all the iso frenzy, people
>> seem to have forgotten about the good ole infinite primitives. They
>> still have their uses.
>>
>Out of curiosity, what uses?
>I.e. how is a "truly infinite" quadric cylinder better than a regular cylinder
>scaled so long that POV considers it infinite?
Attitude :) *I* will know that I've cheated with the latter.
Peter Popov ICQ : 15002700
Personal e-mail : pet### [at] usa net
TAG e-mail : pet### [at] tag povray org
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