Do you know that the free Sketchup has a huge of differents "free style" ? ;)
http://sketchup.google.com/intl/fr/

So just export in skp format from Moi to Sketchup, reload it in sketchup, choose your style!
That's all :)
you can't find more simple! You can also with Blender but you must learn Bender :D:)
With Sketchup nothing to do :)

from a model found on the net ;)


before (here i render with Kerkythea or Twillight render or Renderin or Podium or Light Up etc...all plugins of Sketchup )



after apply a preset style!