Starting a new #BIM #BIMproject on #Revit first get the #surveyor #AutoCAD plan with #geolocation and correct #coordinatesystem. How to set geolocation on basic AutoCAD (if you don't have #Civil3D or #Map3D) look in this video. In #BEP provide project #InternalOrigin, #SurveyPoint, #BaserPoint coordinates and how these coordinates will be exported to IFC. If you are planning to model a topo surface be careful. In most cases, the surveyor provides plans to the #architects with eliminating 50% or more data of survey points. So don't make topo surface from 2D CAD plans. Ask for the 3D surface model from the surveyor he will make a precise model with all the needed points and corrections. He can access all needed data for such work by combining #photogrammetry, #laserscanning, and measuring individual points.