Sweep problem?

How come I can not run a sweep for these binaries? (It is an surface of ​​Moebius). How can you do in your opinion? Is impossible to do with Rhino?


Sweep problem.3dm(172.3 KB)

Hi davide,

Use Loft instead or Sweep here and you get what you’re after… no cross section needed.

Thank you Brian, I had not thought of using the loft. Why does not work the command “sweep 2” to generate this form? (composed of two rails and one rail)

I don’t know but suspect it has something to do with the twisting normal. If you draw a line between the mid snaps of the rails and then split them with that line, you can do two separate Sweep2 srfs. I suppose if you needed a curved wall to the strip a custom cross section would be needed and this method would allow for that.

This seems like a special case. If the two other options don’t work for you please let me know.

Its probably a legitimate bug. I’d have to run it in the debugger to see why it doesn’t work right.
If you move the curve endpoints apart a little bit it works, so it probably falls into some special case that it shouldn’t.
If the code that generates sweep frames decides the surface should be closed, there will be a problem since the surface normals are opposite at the seam.
Since the curves aren’t closed, it seems like the sweep frames should be made correctly.