How far from the Revit file's origin are the model parts you are showing?
How big is the site model? (Overall dimensions, not file size.)
Is the site model made of Revit objects, or is it imported from AutoCAD (Civil 3D or otherwise)? If so, even if the site model is fairly compact and close to the Revit origin, could there be something in the site model that is far away from the area of interest? If you open the site model in AutoCAD and zoom extents, does is zoom way out, leaving the area of interest a small dot on the screen?
David Koch
AutoCAD Architecture and Revit User
Blog | LinkedIn
