I need a cog that will operate a single door with a switch or by activating the door itself. The catch is that it needs to be able to swing open. Is it possible to make a swinging door using frames just like most door cogs? If it is, it would be great if someone would be willing to write a cog to do this.

I'm probably mistaking (as I haven't used level cogs for aeons), but can't you use a standard door cog and have the second frame just rotated and positioned correctly? If not, then I'm sure there must be thousands of swing-door cogs around, as this is a pretty basic problem that was probably solved 5 years ago or something.

Did you even look in the tutorials section?

http://www.massassi.net/tutorials/rd/tutor.htm
http://www.massassi.net/tutorials/rd2/tutor.htm if you need MotS compatible version.

Don't use frames. It won't look right (the centre point of the 3do will move in a straight line, not curve as it should, so the door will appear to move in to the frame as it "swings")

That's funny. I really didn't think of going to the tutorials. I must have skipped that one because I've never wanted a swinging door before. It looks like the tutorial will help me. Thanks guys.

Just create a new door 3do and put the index node at the left side by cleaving a square in your new door and having it highlighted when you export the sectors as a 3do... the door will move on the node.