I mocked up my Little Women set in Sketchup!  So far I’ve just set up the kitchen and the living room.  Sketchup’s been a great help – I can export images at any angle I want, then load those images into MangaStudio and use them as a quick reference to help set up perspective lines and such.  It’s been a great help when it comes to keeping things where they’re supposed to be and with elements I tend to have a difficult  time drawing, like windows and doors.