You wouldn't beleive the hassle we've been having.
Just recently, we had to submit a design survey to a team that was using Acad 2002 with Eaglepoint. That was a nightmare. According to them, Eaglepoint does not do LandXML, and for some unknown reason C3D flattens all C3D objects to Z=0 when they are exported to Autocad. This means that they couldn't even explode objects to get elevated contours and TIN lines after we converted it to Autocad 2000 format.
Finally, I ended up importing the XML into Land Desktop, and then created 3D-Lines of the surface in Land Desktop. At this point, I noticed that the XML Export of the surface from C3D DID NOT include the surface boundary...
So I had to go back to C3D, pull the boundary out of there, and block it into Land Desktop. I added the boundary to the surface and reimported the 3D-Lines to give him a surface with clean edges, then converted the DWG to 2000 format. That worked.
What a hassle. Some people around our office are tempted to completely drop Autodesk because they don't seem to realize that WE NEED TO SHARE DATA WITH OTHERS!!!!! We can't keep dealing with this conversion hassle. If it weren't for the power of C3D, Autodesk would have already been dropped. I hope Autodesk realizes what a thin line they are walking.