Note: There is a newer version of this specification see VEC 2.0.2
The Curve3D is an abstract representation of a curve, that defines the three-dimensional appearance of the centreline of a segment. The concrete type of the curve (e.g. NURBSCurve) defines the mathematical function that applies to curve and stores the required parameter set for this function in the VEC.
Specifies an ordered list of curves which describe the centerline of the segment. If a segment is described by more than one curve, the centrelines of the individual curves are aligned in the order of this association.