No matter what your preference is for 3D design: hand sketches, Revit, SketchUp, or Rhino; You should be following the work of Jim Leggitt. Jim is the master of mixing 3D computer modeling and the hand drawn look. Best part is he shares his process weekly. Check out his blog here and be sure to add it to your RSS Feed. Enjoy!
Jim also has a book out made from his blog… Looks like a winner!
Image above is from Jim’s blogpost: Urban Design Visulization