LEO_BOLOGNA nous apporta ses lumieres en ce 04/05/2006 09:56:
> Hello everybody,
> 
> I need to convert a NURBS in a mesh format...
> My problem is that my NURBS is modeled and stored using a tool (called
> xcmodel) developed and used in my university...
> in this file are specified: surface degrees (2,1), the control net dimension
> (10 x 4), the knot partition dimension (13 x 6) and finally the coordinates
> of every control point and knot...for every control point is specifed the
> weigth also..
> How should I use these informations to obtain a mesh format recognized by
> povray?
> 
> Thanks,
> Leo
> 
> 
> 
> I post the content of my nurbs file:
> 
> DEGREE_U_V
>        2        1
> N.C.P._U_V
>        10        4
> KNOTS_U_V
>        13        6
> COORD.C.P.(X,Y,Z,W)
> 0.000000e+00 -4.519998e-01 0.000000e+00 1.000000e+00
> -2.200000e+00 -1.200000e+00 0.000000e+00 1.000000e+00
> -2.200000e+00 -1.200000e+00 -1.099995e-01 1.000000e+00
> 0.000000e+00 -4.519998e-01 -1.100000e-01 1.000000e+00
> 0.000000e+00 -4.519998e-01 0.000000e+00 1.000000e+00
> 2.200000e+00 -1.200000e+00 0.000000e+00 1.000000e+00
> 2.200000e+00 -1.200000e+00 -1.100000e-01 1.000000e+00
> 0.000000e+00 -4.519998e-01 -1.100000e-01 1.000000e+00
> 0.000000e+00 -4.519998e-01 0.000000e+00 1.000000e+00
> 2.200000e+00 -1.200000e+00 0.000000e+00 1.000000e+00
> 2.200000e+00 -1.200000e+00 -1.100000e-01 1.000000e+00
> 0.000000e+00 -4.519998e-01 -1.100000e-01 1.000000e+00
> 0.000000e+00 -4.519998e-01 0.000000e+00 1.000000e+00
> 2.200000e+00 1.199999e-01 0.000000e+00 1.000000e+00
> 2.200000e+00 1.199999e-01 -1.100000e-01 1.000000e+00
> 0.000000e+00 -4.519998e-01 -1.100000e-01 1.000000e+00
> 0.000000e+00 -4.519998e-01 0.000000e+00 1.000000e+00
> 2.200000e+00 1.199999e-01 0.000000e+00 1.000000e+00
> 2.200000e+00 1.199999e-01 -1.100000e-01 1.000000e+00
> 0.000000e+00 -4.519998e-01 -1.100000e-01 1.000000e+00
> 0.000000e+00 -4.519998e-01 0.000000e+00 1.000000e+00
> 3.278255e-08 5.599999e-01 0.000000e+00 1.000000e+00
> 3.278255e-08 5.599999e-01 -1.100000e-01 1.000000e+00
> 0.000000e+00 -4.519998e-01 -1.100000e-01 1.000000e+00
> 0.000000e+00 -4.519998e-01 0.000000e+00 1.000000e+00
> -6.600000e-01 -3.200002e-01 0.000000e+00 1.000000e+00
> -6.600000e-01 -3.200002e-01 -1.100000e-01 1.000000e+00
> 0.000000e+00 -4.519998e-01 -1.100000e-01 1.000000e+00
> 0.000000e+00 -4.519998e-01 0.000000e+00 1.000000e+00
> -2.200000e+00 -3.200002e-01 0.000000e+00 1.000000e+00
> -2.200000e+00 -3.200002e-01 -1.099998e-01 1.000000e+00
> 0.000000e+00 -4.519998e-01 -1.100000e-01 1.000000e+00
> 0.000000e+00 -4.519998e-01 0.000000e+00 1.000000e+00
> -2.200000e+00 -3.200002e-01 0.000000e+00 1.000000e+00
> -2.200000e+00 -3.200002e-01 -1.099998e-01 1.000000e+00
> 0.000000e+00 -4.519998e-01 -1.100000e-01 1.000000e+00
> 0.000000e+00 -4.519998e-01 0.000000e+00 1.000000e+00
> -2.200000e+00 -1.200000e+00 0.000000e+00 1.000000e+00
> -2.200000e+00 -1.200000e+00 -1.099995e-01 1.000000e+00
> 0.000000e+00 -4.519998e-01 -1.100000e-01 1.000000e+00
> KNOTS_U
> 0.000000e+00
> 0.000000e+00
> 0.000000e+00
> 1.250000e-01
> 2.500000e-01
> 3.750000e-01
> 5.000000e-01
> 6.250000e-01
> 7.500000e-01
> 8.750000e-01
> 1.000000e+00
> 1.000000e+00
> 1.000000e+00
> KNOTS_V
> 0.000000e+00
> 0.000000e+00
> 3.333333e-01
> 6.666667e-01
> 1.000000e+00
> 1.000000e+00
> 
> 
You may get by by converting your data into a collection of bicubics patches. The
trick is to 
correctly assign each knots and control points to the correct parts of the POV-Ray's
bicubic patch.

-- 
Alain
-------------------------------------------------
Feminism: Men are shit.

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