Not sure STL that will be paradisiac ;)
If i remember! :)
http://moiscript.weebly.com/r2d3.html

but try also the _importBj by Max Smirnov
maybe that can works no so bad for your piece!
http://moi.maxsm.net/files/scripts/ImportObj.v.1.5.2015.09.10.zip