Hi PaQ, so yes there is a 32-bit limit that you ran into there. The limit is that any one "chunk" of the .3dm file can't be greater than 2GB in size for v4 and earlier 3DM versions and currently MoI writes a Rhino v4 .3dm file by default when creating a brand new file.

Rhino v5 .3dm files instead have 64-bit chunk sizes so they don't have the 2GB limit.

I could set MoI to generate Rhino v5 .3dm files by default instead of Rhino v4 .3dm files, but it's not that great of a thing to be messing with right at the very end of a beta cycle. For now I'll set up a moi.ini flag that will let you set it to write Rhino v5 .3dm format and in the next MoI beta if you set that then you should be able to generate massive files ok.

- Michael