Actually really like the viewport render right now...perhaps just a photoshop airbrush pass for enhancement and keep the nice clean technical lines?

I'll be watching this project, very nice.

Thanks for viewing and for your feedback. I've rendered the model using cinema 4d internal renderer, and made some changes to the proportions...then airbrushed in photoshop All modeling is still sketchup, thanks to collada export. This site is good motivation to keep working on these studies, people here are responsible for very impressive work done very quicky

Brilliant and inspirational...fascinating to see what these structures looked like

Alcatraz inspired guard tower...trying to get back in the habit of doing studies in sketchup. Some work on railings and materials in order, and some supplemental details on roof and interior of tower.