Hi Lish, the ideal way to do a revolve like this is actually with one segment open, instead of having a segment directly on the revolve axis.

So for example if you want to pivot around the bottom line your profile would ideally look like this:



Basically, if MoI really tried to revolve that line that was directly on the revolve axis, it would be a revolve of a line around itself, making a collapsed surface there. There is something that tries to automatically remove such lines to prevent this problem from happening, but it seems to be running into a bug in this situation, I'll take a look and see if I can fix it up.

But if you don't create that line segment that MoI needs to remove, your revolve will work properly.

- Michael