How I work
If I have access to CAD files I remove any unnecessary objects or linework. If there are no CAD files available, I create them from hard copy blueprints or do a site measure and create my own.
I bring the CAD linework into a 3D program like Sketchup, Revit or 3DS Max and set up an 'outline' of what the 3D model will look like.
I use the CAD linework to create 3D geometry for the major shapes.
I begin to add details like roofing and decks.
I add site considerations like driveways, trees and pools.
I texture, light and render the model for presentation.