Hi Bob,

Just to add to this, is there any particular reason why those surface lines are a concern? If the sweep surfaces are tangent to each other those surface lines won't affect anything down the track, they won't show up in rendering and will not affect any post processing like 3d printing or cnc machining, this is normal in nurbs modeling, on the other hand if the surface to surface continuity is not tangent then yes, Burr has the answer to correct this, as they will show up in rendering etc. as a kink or imperfection.

Cheers
~Danny~