DJ Wiza nous apporta ses lumieres en ce 25/04/2006 06:07:
> scott wrote:
> 
>> Try MegaPOV if you haven't already, I found that with the original POV 
>> I get many bugs and sometimes parse errors when using splines and 
>> sphere sweeps. MegaPOV seemed to fix it. Also I found replacing the 
>> sphere sweeps with spheres connected by cylinders made render times 
>> much faster and without much loss to quality (you should choose a good 
>> spacing for the spheres). Just my 2 cents.
>>
>>
> 
> I installed MegaPOV and it works.  No more disappearing sphere_sweeps!
> 
> About the use of spheres and cylinders...In theory, shouldn't a 
> sphere_sweep using linear_sweep look exactly the same as spheres 
> connected by cylinders?  If so, why doesn't POV-Ray break it up like 
> that?  I'm finding that POV-Ray is shooting way more rays to test the 
> sphere_sweep than is probably necessary...only 1-2% of the rays tested 
> result in a success.  That certainly can't be efficient.
> 
> -DJ
When you shoot rays at a sphere_sweep, you need to cover the whole bounding box, witch
in turn, must 
completely enclose the whole extent of the sweep. In most cases of large sweeps, the
bounding box is 
almost empty, leading to very poor success percentages, and extended trace times.
Breaking the sweep 
in smaller sections and puting those in an union can realy improve the effeciency.
In practice, a sphere_sweep using linear_sweep DOES looks exactly the same as spheres
connected by 
cones as the radius can vary. As a bonus, you get rid of those pesky artefacts by
using spheres and 
cones.

-- 
Alain
-------------------------------------------------
WARNING: The consumption of alcohol may make you think you can logically converse with
members of 
the opposite sex without spitting.

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