No support of b-splines within current IFC implementations [added 2008-02-26 & 2010-03-01]
Based on IFC2x3
Initiator ISG Meeting-Berlin
Effects Extended Coordination View
Date 2006 02 24
The b-splines as definined in IFC:
are not supported by implementations in any case (not in profiles, nor in 2D Geometry).
[added 2008-02-26] It is an error to export a b-spline (being IfcBezierCurve or IfcRationalBezierCurve) as part of an IFC2x3 coordination view exchange file.
[added 2010-03-01] Reconfirmed for Coordination View Version 2.0, b-splines are excluded from scope