Sweep 2 surface issues

In Rhino 7 sweep 2 no longer produces a clean single surface using the inputs I am accustomed to. In Rhino 5 or 6 using 2 rails and a contour curve almost always provided a single surface in the profile I was looking for. In Rhino 7 ( using the same inputs ) I always get a series of surfaces patched together as a polysurface.

Rhino 5.0.

Yellow lines are rails, red is contour curves for sweep. This creates a single surface that is exactly what I am looking for.

Rhino 7.0

Exact same setup as above ( Rhino 5 ) - yellow lines are rails, red is contour curve… but in Rhino 7 this same instruction now creates a polysurface that is made up of 9 surfaces linked together. Can’t figure out how to eliminate this result and force the command to create a single surface as per previous versions.

Any help appreciated.


Hello - probably, using the ‘Refit Rails’ setting in V7 will sort it out but please post a file with all of the input objects, if you cannot solve it.


Refit Rails setting corrected the issue. Thanks. Curious as to the reasoning behind the change… what would be the functionality of the change in the tool settings from version 5/6 ?

Hi Steve- the change was so that simple cases like a rail with tangent arcs and straights could keep that relatively simple structure and not be refit into a complex G2 curve.