Thanks for the tips, very useful.
Tested an export from rhino to step to see if blocks will be recognized that way. It doesn't work.
Still have to fight with a few nasty big files. Like 200 mb with instance and blocks and 2 GB without ...
will try the explodeblocks commands...

Must be the first next feature to be implemented in my opinion. Then it's going to be pure heaven.

Totally agree wastzzz!