I'm going to post a "slipping" spiral mpg animation at the
binaries.animations group and the script used to make it at
text.scene-files too (several minutes from now). It's a obvious cheat to
get the spiral to slip past itself at 3 distinct radii. Maybe completely
useless or maybe a way to fake it depending on what exactly is needed. The
main textures could be anything really.


Bob Hughes wrote:
> 
> I can help out with the 3rd thing anyway. Use UVPov Alpha 5, which has
> been recently updated; it's a custom version of POV-Ray by Nathan Kopp. It
> can cast light through objects and produce a spectral dispersion. URL is:
> 
>  http://nathan.kopp.com/patched.htm
> 
> There are certain things you may need to know about using it that may be
> found in the newsgroups povray.unofficial.patches and povray.general if
> you search for uvpov or photons. Or just ask any questions there if having
> a problem.
> 
> Gilles ADAM wrote:
> >
> > Hello...
> >
> > 1 - I use PoV 3.1 to model various astronomical phenomena (animations
> > to be soon on the WEB...), and general physics phenomena for education.
> > I recently modelled (artist's view only, as only a rough sketch
> > of the physical processes is available !)
> > the central parts of an active nucleus galaxy (the thing with a black
> > hole in the center), made it rotate, and so on. Nice, but it rotates as
> > a solid
> > object, which is wrong. Does anybody know of a way of "warping"
> > continuously the "spiral" texture to make it rotate faster in the
> > central
> > parts than in the outer parts ? I searched a lot in the (excellent)
> > in-line doc, with no success...  Maybe I missed something...
> >
> > 2 - I am going to try to write an external program computing a B-spline
> > approximation to a set of points ( two sets in fact, one for the camera,
> >
> > the other for the "flying object" ) The best way I know so far is using
> > PCG2.21 (Patrick's Curve Generator), which takes as input the clock
> > variable
> > and a spline.dat ASCII file containing the knots of the path, and
> > outputs
> > an ASCII file wtih a set of #declare. The whole thing is invoqued via a
> > Pre_Frame_Command in the .ini file. This is the structure which is
> > planned for the code I am about to write. But the PGC program does not
> > compute the local curvature and twist of the 3D spline, which are needed
> > to
> > compute the "correct" attitude of the plane, and cannot compute two
> > distinct
> > spline approximations on two data sets for the same clock value.
> > The "spline" add-on from Chris Colefax is not well suited for multiple
> > knot
> > splines, as you must give all the control points to be used for all the
> > knots;
> > or did I miss something ?
> > I tried AnimSys, too, but the "plane" attitude is not computed from the
> > fly path shape, just given a priori.
> > Before engaging further into  development, I would like to know
> > if anybody heard about something addressing this problem...
> > It should have been solved by all the people working in the flight
> > simulation
> > area...
> >
> > 3 - I used (before switching to the last release of PoV for Windows) the
> >
> > dispersion patch. I was able to render all kinds of gems, to demonstrate
> >
> > refraction into complex objects during physics courses. Great, but I was
> >
> > not able to obtain a spectrum-like patch of light on a screen following
> > a glass ball, although I got nice effects in the ball itself.
> > Is that normal, or just a matter of wrong code ?
> > I tried to disperse light through a prism, and get a spectrum on a
> > screen :
> > no result...
> >
> > Many thanks to the fabulous POV team !
> >
> > Gilles AdamObservatoire de Lyon
> > 69561 Saint Genis Laval cedex
> > France
> > ga### [at] obsuniv-lyon1fr
> 
> --
>  omniVERSE: beyond the universe
>   http://members.aol.com/inversez/homepage.htm
>  mailto://inversez@aol.com?Subject=PoV-News

-- 
 omniVERSE: beyond the universe
  http://members.aol.com/inversez/homepage.htm
 mailto://inversez@aol.com?Subject=PoV-News

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