Hi Lars,

> Hi Michael, haven't figured out how to use the MakePeriodic command
> yet, it produces this result:

Hmmm, well that is a weird result. Is the surface possibly trimmed?

This looks like a different model than the one you posted previously? If you can post a .3dm with this surface (before doing MakePeriodic on it) I can take a look at it to maybe tell what is going on there.

- Michael