Oh yes, how do you use this thing? First of all, very carefully. Getting the fundamentals of the simulation library working took much longer than I expected, so numerous loose ends remain to be cleaned up. Just because my demo works beautifully doesn't mean you can use it; a sufficiently advanced technology is indistinguishable from a rigged demo!
Load the IGES application with the command:
(xload "iges")
To create an IGES file of the current drawing, use the command:
XIGESOUT filename
To load an IGES file, bring up AutoCAD on a new drawing, then enter the command:
XIGESIN filename
Other than some diagnostic messages generated as the local copy of the database is prepared, the text screen output is identical to the built-in IGES commands (at least until it crashes).