Thanks for your reply SteveMacc, most of the surfaces will marry up, but the naked edges are not what the problem is, or I assume not - All of the surfaces need to have a fillet or blend applied first, and then they would be joined up after that process. If I join tem up now, the fillet wont work as the surfaces are joined - pop them apart again and it will work. If there was an Isocurv extraction facility then it would be as easy as trimming and then either blending or doing a 3 point arc and a twin rail sweep.

Martin