Hi Felix,

> Lastly for some reason the button get rotated about the normal
> of the 2 curve used for the sweep where they intersect (see joined
> image, red line). Just in case, I've rotated

Can you post the 3DM model file for this case where you're getting unexpected rotation?

It could be that you're seeing the result of uneven parameterization of the sweep surface. One thing that is good about the curve to curve flow is that it is based on distance traveled along curves.

The surface to surface flow is not based on 3D distance but rather parameter space distance, and it can be possible for parameter space to be compressed or stretched in relation to 3D space. When that is the case it will result in compression or stretching of the surface-to-surface flow as well.

Right now I think that you can get that kind of uneven parameterization if you just draw a control point curve with fairly uneven spacing between the points and use that for a part of the sweep. You can use the Rebuild command for now to reconstruct a curve with uneven parameterization in it, and then using the result of the rebuild for constructing the sweep may give you a better result.

But that is one nice thing about the curve to curve one as compared to the surface-to-surface one - that the curve-to-curve one is arc length based and is not sensitive to parameterization like the surface to surface one.

- Michael