Hi Michael,
now that's what I call efficiency and user-friendliness! Having the developer of your favorite software calculate formulas for you while chewing his cereals! Thank you very much, that's exactly what I needed to know!
Actually, a few hours after posting my request, I came up with the same procedure you showed me (without the offset formula though) and it works perfectly. Anyway, with particularly complex curves, I found out that it's best offsetting only the straight segments and do the blending of the corners one by one manually. That's because the offset command tends to add points in the corners. This way I make sure that the two curves that I'm gonna loft have the same number of points.

And now your questions:

>Do you expect a positive angle to go "outwards" and a negative angle to go inwards?
>Or is that reversed from what you'd expect?
>The angle is measured with the straight extrusion direction being 0 degrees, right?

Instinctively I tend to consider angle measures increasing in a clockwise direction, (with the 0 at 12 o'clock) so I'd say the reverse.

>Do these things always happen on planar curves, or is there some construction that you would expect to be able to do on a non-planar curve?

Definitely only planar curves. I don't dare to imagine what a mess should be implementing this command on nonplanar curves!!! lol

>Are these always done on a closed loop, or do you need to do them on some open curves like a line segment?
Although I use the command mostly on closed border loops it should be nice for it to work on open segments too.

>On things with sharp corners, how would you expect the corners to be filled in?
This is my wishlist:
Three options - Detached surfaces, Chamfer, Fillet
The Fillet option giving the possibility to choose the tangency (circular, G1,G2)
If this is too much, having a default chamfered result would be the best solution. The filleting can be done manually afterwards.

Hope that helps, have a wonderful day and thank you again!
Daniele