CREATELINE3D Create a line with various inputs.

   Line is represented in a parametric form : [x0 y0 z0 dx dy dz]
       x = x0 + t*dx
       y = y0 + t*dy;
       z = z0 + t*dz;


   L = createLine3d(P1, P2);
   Returns the line going through the two given points P1 and P2.
   
   L = createLine3d(X0, Y0, Z0, DX, DY, DZ);
   Returns the line going through the point [x0, y0, z0], and with
   direction vector given by [DX DY DZ]. 

   L = createLine3d(P0, DX, DY, DZ);
   Returns the line going through point P0 given by [x0, y0, z0] and with
   direction vector given by [DX DY DZ]. 

   L = createLine3d(THETA, PHI);
   Create a line originated at (0,0) and with angles theta and phi.

   L = createLine3d(P0, THETA, PHI);
   Create a line with direction given by theta and phi, and which contains
   point P0. 


   Note : in all cases, parameters can be vertical arrays of the same
   dimension. The result is then an array of lines, of dimensions [N*6].

   See also:
   lines3d

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   author : David Legland 
   INRA - TPV URPOI - BIA IMASTE
   created the 17/02/2005.

Package: matgeom