I'm not seeing anything obvious that would make the dwg so large.
You do have the 3D roof tiles on a non-showing layer?
Can you post a screen shot of the DWG? ( use the Print screen button above insert and then paste into a photo editor)
As discussed elsewhere, if you only show part of the available drawing on a plotmaker layout, when you publish a dwg it saves all of the drawing. That said, are there areas of your model outside what you show in your roof plan layout that might have a lot of facets like the roof tile curves?
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"