Hi niko, the "maintain tangent" option in MoI does not do the same kind of a thing as what you were thinking.

It does not adjust the tangent to adapt to a surface edge, instead it makes the sweep work by moving the profiles only in parallel planar slices instead of sliding them along the rails where they can potentially get twisted from their original orientations.

You also can only use it with some particular configurations, like when the profile curves are all on parallel planes to one another and share a common tangent direction on one side.

I probably should have called it something like "Position profiles along parallel planes" or something like that instead, but it was a bit difficult to describe.

See here for some illustrations and description of what that option in MoI actually does:

http://moi3d.com/forum/index.php?webtag=MOI&msg=2908.13
http://moi3d.com/forum/index.php?webtag=MOI&msg=2226.11


It's totally different than the continuity options that you were using in Rhino.


> In Rhino I used a 2 rail sweep with the curvature option on and
> it came in super smooth.

Maybe you were using different curves for the rails than I was? Or is that something new in Rhino v5 where you can adjust continuity for a profile curve instead of only along the rails?

But yeah if you are using the continuity options, that's something that MoI does not have yet, you currently need to use Rhino if you want to have continuity adjusted for Sweep or Network.

I do plan on working on adding those to MoI in the future.

- Michael