I'm creating a pulley which requires a slight arc to for the endless drive belt. I've created the arc but when I sweep it along the round rail the arc looks to be made up of 4 straight lines instead of one curved surface. Is this just an artifact of the way MOI renders the sweep or have I missed something?

Just a display artefact for speed the process of display the view!
Internal Geometry is perfect!
You can change the display by Options / View / Mesh Parameters - Add Detail to inflections

Hi Guy yes that's just a display artifact. Some more detailed info here:
http://moi3d.com/forum/index.php?webtag=MOI&msg=10580.2

- Michael

In Options > View > Mesh angle: set it up to something like 3.

Wow, that helped a lot.
Never thought was a graphical artifacts but a program node within itself.
Glad to sorted that one out.

its easer to figure out the final product this way.
Too many artifacts usually confuses me (even though its an aproximate),,..

Thx...