Get back to small coordinates system

[berson.guillaume]

Hi,

I know all the problems us surveyors have with large coordinates systems. I know it is recommended to work with small coordinates, but I have a problem with an old revit file with large coordinates.

I have two point cloud (one made in 2016, and one made in 2018) in the exact same coordinates system. They both overlap perfectly in AutoCAD. But they have arount 1m shift in Revit. Moreover, I can't move those clouds with precision, they can only move 1m in each direction. This is 100% due to large coordinates.

My question is, what can I do now ? I need to keep working with this revit file with my new point cloud, but I obviously can't. Is there a way to switch everything to small coordinates ? If so, could it be the solution ?

Thank you.

[SteveKStafford]

It isn't the large coordinates, the values. It is the extents, how far specific elements in the file are from each other. The overall cloud (all the points) can be very very far from the origin as long as the size of the cloud itself is not too large (20 mile diameter).

It sounds like you need to clean up the cloud so that only the points that are actually relevant to the building (assuming a building) are present. Then you should be able to link the file without any complaints, place it at/near Revit's own origin.

[berson.guillaume]

Hi,

Thanks for your reply. My point clouds are OK, they have large coordinates but the size is only around 200m long. But because I'm using shared coordinates, my Survey Point is at 0.0 while my Project Base Point has large coordinates. So yes, the extents of my whole project is around 8 millions meters...

[SteveKStafford]

You can't move the Project Base Point (PBP) unless you un-clip it and that does not move Revit's origin. The only way your model is far from Revit's origin is if you link the data and leave it very far away. They recommend you move the survey/cloud data close to the origin.

If you see large coordinate values listed in the PBP that doesn't mean your PBP is far away. The values shown is for the Shared Coordinate System, it indicates how far away the Survey Coordinate origin is. The clue is that the label above the coordinate values is Shared Site:

If you un-clip the PBP and right click > choose Move to Startup Location...if it doesn't move then that's the origin of the Revit project.