I didn’t realize it was so difficult to map indoor (3D) from AutoCAD floor plan drawings until I had to work with it this summer. It is just the beginning, and it already took us four months to convert 80+ buildings into somewhat 3D, floor by floor. Topologically there are a lot of problems with the original AutoCAD in GIS perspective, e.g. non-closing polygon, non-connecting lines, annotation in the wrong spot etc.. We manage to get a kick start this summer and definitely a lot more work to come in the near future!
Creating 3D floorplans have a lot of benefits, from simulation to modeling to navigation to visualization. I was very lucky to work with two talented under-graduate students at York University.