Thanks. I’ve read through that before so I’m not sure why I convinced myself relative tolerance was what does it. Maybe i just need to play more. For what it’s worth, /most/ times I haven’t had an issue and the workflow is actually really helpful. Recently I had a stubborn object that just wouldn’t import properly into revit (read: it couldn’t ‘explode’) and so I started trying to tease the source of the issue out of rhino. Perhaps it is only my absolute tolerance that needs to be set low. I’m convinced it’s edge tolerance that needs to be kept low though so whatever dictates that.