I have found that a ‘false offset’ issue occurs when defining Shared Coordinates via 'Acquire Coordinates' when using DWG files stamped with a given coordinate system definition, such as when using Surveyor base files.
Revit is unable to parse the Geolocation stamp in the DWG and instead uses the projection’s Easting and Northing offset from the meridian and the equator, as defined within the stamped projection, in addition to the ‘true’ coordinates of the projection.
This results in a corresponding shift in XY of the coordinate system which ignores the location of the XYZ origin in the World Coordinate Sytem (WCS) in the DWG.
Workaround:
Removing the stamped Geolocation in AutoCAD 'simplifies' the DWG for use in Revit, and the Acquire Coordinates tool works as expected.
The coordinate system name/definition is however set to 'Unknown'.
Desired Workflow:
It would be helpful if Revit could correctly parse the Geolocation definition (or at least the designation) resulting in consistent Shared Coordinate system coordinates mirroring the WCS XY Origin in the source DWG.
Note:
This occurs in DWG files which have a Geolocation stamp with or without a User Coordinate System definition(s), as well as DWG files with only the WCS definition.
