CIRCLE3DORIGIN Return the first point of a 3D circle.

   P = circle3dOrigin([XC YC ZC R THETA PHI])
   P = circle3dOrigin([XC YC ZC R THETA PHI PSI])
   Returns the origin point of the circle, i.e. the first point used for
   drawing circle.

   See also:
   circles3d, points3d, circle3dPosition

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   author : David Legland 
   INRA - TPV URPOI - BIA IMASTE
   created the 21/02/2005

Package: matgeom