It sounds like there might be a problem with a bad library part or inverted slab or something of that nature. Have you received any error messages prior to this?
Try marqueeing smaller areas of your model and generating 3D from it to find the part(s) of your model that are causing this behavior. If only some of your elevations are causing this then that is a good clue as to which part of the model may be problematic.
Which libraries and add-ons are you using?
Erika
Architect, Consultant
MacBook Pro Retina, 15-inch Yosemite 2.8 GHz Intel Core i7 16 GB 1600 MHz DDR3
Mac OSX 10.11.1
AC5-18
Onuma System
"Implementing Successful Building Information Modeling"