So, I tried to sweep a profile along a helix.
The first attempt gave a twisted result (for a FLAT sweep)...

Then I rotated the helix so that it went through the Z Axis,
and it gave me the intended result.

So, for better understanding later on:
"what's the exact reason that they swept differently?"

PS: it was on Moi v4.

Hi Elang, when you do a sweep with the "Twist: Flat" option, it means that the profile will pivot around a one specific direction and won't do any "banking".

The default for the fixed rotation axis direction is the z axis.

If your helix is oriented around the z axis then the default direction matches what you need so you don't need any further action.

If your helix is oriented around some other direction like the other one you show, then you need to tell the Sweep command about that direction so it will use it instead of the default z axis direction.

The way you tell it is by pushing the "Set flat direction" button that appears in the Sweep command options when Twist = Flat is set, as shown here:



- Michael

Thank you very much, Michael.

Cheers!