Hello,

I'm trying to make a certain surface from a 3D sketch. It should be a smooth curved surface touching the boundaries of the sketch, and the highest point of the curve should be along the centerline. Please take a look at the file I added (it is copied from big part which I can't post here, so sketch is not fully defined).

I'm trying to achieve this with Filled Surface. I drew another sketch to mark that centerline and to act as Constrain Curve.

The problem is that the resulting surface is warped and not smooth. If I delete the feature and create it again, at first build it is smooth, but when I force rebuild it - it is warped again.

I'm not sure what is wrong here. Can somebody please help me out? Do I need some additional Constrain Curves? I tried, but the results are very bad.

P.S. I know I could achieve similar surface with Loft instead, but I have to use Surface Flatten later, and when I try to flatten Loft, it gives very bad results, while flattened Filled Surface works like a charm.

I'd really appreciate any help.

File is in 2015 format.