There was a time I thought I understood the Revit coordinate system. Project base points and survey points, it seemed straight forward. Then a few years ago I learnt about the 'hidden' internal coordinate system in Revit that Origin to Origin uses and I started to pay a little more attention.
The problem for me with shared coordinates is that it is not an area of Revit I use on a regular basis. I would typical mess with it at the start of a project to set up files and consultants links, then be working on the project for 6 months and forget it all. I wrote a 3 page step by step process to help and have referred to it ever since.
Some months ago though I was troubleshooting a shared coordinates problem with a colleague. We had a consultant link not playing ball and I was getting unexpected outcomes trying to fix it. It made me realise perhaps I hadn't grasped the Revit coordinate system as well as I had thought...until now.
I recently watched an Autodesk University presentation by David Baldacchino. You may recognise the name if you are a reader of his blog 'Do U Revit'.
The presentation he gave 'Navigating through the storm using coordinate systems in Revit' is definitely worth the watch. Its full length is around 90 minutes and if you visit the link you will find handouts and resources to go with the presentation. Thanks David!!