Fatal Error in Civil 3D 2018.3? Author: rkmcswain September 4, 2019 If you are running Civil 3D 2018 with the .3 update installed, and you are receiving a fatal error while creating a best fit alignment, then the solution, according to Autodesk is….. Tweet Reference, Tech Autodesk, Civil 3D, Civil 3D 2018, crash, Fatal Error