In AutoCAD, the origin is the WCS. It never changes and is baked into every DWG file. In Revit, you tell the project file where you want the origin, but you can choose the Shared Coordinate system (which is visible via the Survey Point), or use the Internal Coordinate System (which is invisible but can be read through spot elevations). Where things can go haywire is when you start moving the Survey Point unpinned and pinned, which can alter the Internal Coordinate System. My suggestion is just to use the Shared Coordinate System and manually set it to where you want it to be, but it's best to choose something easy like grid line A,1 at 100ft for Level 1.