Hi simba, so I did a bit more investigation, and the specific issue is that your scaling rail doesn't quite extend far enough. One part of how the scaling rail works is that it interacts with a vertical direction from the side rails. But in your case here your scaling rail stops a ways before the end of the side rails and so it does not end up covering the entire range of the sweep.


When a scaling rail does not cover the entire length of a sweep, the sweep reverts to the regular non-scaling-rail version in spots where the scaling rail is not hit, that's what causes that sudden step problem.

So another way to solve the problem is to just extend your scaling rail a ways so that it covers the entire area directly above the rails, like in the attached version. The sweep will then work even using your non-planar profile curve.

It's a bit easier for things to naturally line up with each other if the profile is planar though.

- Michael