in previous versions of Bricscad I could choose the GIS Coordinate System "DHDN.Gauss3d-4, (EPSG:31468)" from the GEOPOSITION Dialog. However, this is not available anymore. Is it possible to import or load this GIS CS again?
This might be a bug. You could consider submitting a Support Request with Bricsys. To submit a Support request login to your Bricsys account and access this link here: New support request | Bricsys
I've reported it to the support. You have to enter coordinates near the location you want to load as Coordinate System. The the list automatically changes to all coordinate systems that are relevant for this location.
"A filtering by geographic location has been added to this dialog recently - it shows coordinate systems in the current location only. So to set the EPSG:31468 you need to choose a proper location within a covered area" - BricsCad Support
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