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Carl nous apporta ses lumieres en ce 09-04-2007 16:49:
> Alain <ele### [at] netscape net> wrote:
>> Possible solution, if the desired cylinder have a ralatively large radius:
>> difference{
>> object{wwwmwww}
>> cylinder{<100,0,0><-100,0,0>,20}//must be longer than your prism
>> //the radius should be reasonably larger that the height of the prism
>> cylinder{<101,0,0><-101,0,0>,17}//longer to avoid coincident surfaces
>> texture{YourTexture}
>> }
>> Here, the faces are curved, but the sides are still parallel.
>> Another way, is to use object pattern with a cylindrical warp to project it
>> on a cylinder. This have the advantage of the sides been perpendicular to
>> the surface. As this is meant for pigments, it must be converted to a
>> function and used in an isosurface (extreem max_gradient) or directly as a
>> media density. Both are slow.
>> --
>> Alain
> Well, ultimately I wanted the logo to wrap 3/4th of the way around the
> cylinder. I was then going to animate it orbiting a sphere. So I don't
> think the difference with a cylinder method would work. I must confess the
> other solution you mention I think is beyond my POV-Ray skill level at the
> moment. I'm still learning. Do you think you could make a simple example
> so I can see what the code would look like?
> Thanks,
> Carl
OK. Logo wraps 3/4 around a vertical cylinder.
In your case, the best way is probably to use some external modeler like Wings
and use the resulting mesh.
The render time will be much faster than that of an isosurface and you can have
specular highlights if you want (impossible with the media solution).
--
Alain
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Honk if you love peace and quiet.
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