Kubotek Forum

120MB is not a large part, I have parts over 700MB!

Layout instances displaying a large number of solids can take quite some time to process if they're HLR or HLD.  This is especially true of there's lots of complex geometry, like springs or helical threaded parts.  You might try setting all instances to wireframe while you're working, and only switching them to HLR or HLD when it's time to print it.