I assume that you have tried opening the DWG in SketchUp, and the AEC objects (Walls, Doors, etc.) were not present.
From a non-orthogonal view (such as SW Isometric), try exporting the file to AutoCAD, using the EXPORTTOAUTOCAD2018 or EXPORTTOAUTOCAD2013 commands. I am not certain what version of AutoCAD Architecture you are using, or if SketchUp 2017 can read an AutoCAD 2018 format file. If you have 2018 or 2019 and your SketchUp can handle the 2018 file format, then EXPORTTOAUTOCAD2018 should work; if not, EXPORTTOAUTOCAD2013 should. That will explode all of the AEC objects to AutoCAD objects. Doing so from a "3D" view should give you some 3D objects, such as 3D Faces. (This is as opposed to doing so from a Top (Plan) view, which would give you linework.) You should be able to see that in SketchUp. (Sorry, I do not have access to SketchUp to test that at the moment.)
David Koch
AutoCAD Architecture and Revit User
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