I am opening .dwg files created in AutoCAD into Auto Sketch. There are circles all over the drawing that I would like to remove. They are group with the building drawing (independent of the dimensional grid) and can not be deleted without deleting the drawing. While opening the file I get a notice that the 3D entities are being flattened. When I view the original dwg in AutoCAD using a co-worker's computer I don't see any 3D entities. Please advise.