i see an open error when using the Kerkythea plug-in and trying to directly launch Kerkythea after generating the output file. so i have to save and close the SU file (or create a new blank one or open another file) before i can open the Kerkythea output file...

You can use several plugins for this. Here is one:
http://rhin.crai.archi.fr/rld/plugin_details.php?id=122
then another one:
http://www.smustard.com/script/DropGC
or you can search for anything containing "drop" in the plugins index:
http://forums.sketchucation.com/viewtopic.php?p=250026

You could also look at Tree[d]
These can be saved as .obj files and imported into SU