These constants define different non-uniform rational Bi-spline flags.

Values:

IG_VECT_NURBS_UNIFORM	The spline is uniform.
IG_VECT_NURBS_RATIONAL	The spline is rational.
IG_VECT_NURBS_MCLOSED	The spline is closed in M-direction.
IG_VECT_NURBS_NCLOSED	The spline is closed in N-direction.
IG_VECT_NURBS_MINTERPOLATE	The curve must be interpolated in M-direction.
IG_VECT_NURBS_NINTERPOLATE	The curve must be interpolated in N-direction.
IG_VECT_NURBS_MFIT	Not currently used.
IG_VECT_NURBS_NFIT	Not currently used.