Quote Originally Posted by HansLammerts
...The Geomarker definition is a feature that can be found in AutoCAD verticals DWG 2013. Apperently, now this is incorporated in DWG fileformat 2018, is that right Steve? Does Revit 2018 only work with DWG 2018 format for this or does it work with the same technique with the earlier DWG (vertical) fileformats?...
I don't know. Revit 2018 is the only version that is aware of the feature. I'd hazard a guess that as long as the GEO Reference information is stored in the DWG file the same way in the earlier version as it is now that Revit could see it regardless. The trouble with the verticals is that some of their smarts are stored in unique formats requiring proxy elements, like contours being a custom element in Civil 3D or Land Desktop.

We might be able to test to find out for sure by creating a GEO Reference in AutoCAD 2018 but saving it to the earlier format?