I've looked at the huge thread on shared coordinate systems, but still feel like I'm walking in the dark. Does anybody have an up to date guide on Revit coordinate systems that they can share, that includes diagrams? I'm finding that talking about project, shared, project startup location, survey point, project base point etc. etc. is extremely confusing when it's done just with words and need a picture fix!

I could also do with a guide on what to do when it goes wrong, e.g. the shared coordinates for two models report the correct values but when exporting to IFC the two models are in different locations (being one current example).

If anyone has any kind of document they could share it would be much appreciated, thanks.