The methods for creating transition surfaces (e.g. fillets, chamfers, etc.), as implemented in many solid modelers, are restrictive and fragile. For example, the extent of a fillet on the two surfaces are linked and cannot be specified separately. Also, both fillets and chamfers yield curvature discontinuities where they meet the original surfaces, which is known to be sub-optimal aerodynamically. In this paper, we present more robust and flexible methods for creating transition surfaces using B-spline surfaces. These methods are solid modeler agnostic, however we’ve implemented them using the Engineering Sketch Pad (ESP).