@gaieus said:
You need not really save it into a new model then reimport. If you group the whole structure you want to scale, and use the tape measure rescaling method while in the editing context of this group, it will only scale whatever is inside.
To scale an entire model with the Tape measure tool:
http://sketchup.google.com/support/bin/answer.py?hl=en&answer=95006
To scale only an entity (i.e. a group in this case):
http://sketchup.google.com/support/bin/answer.py?hl=en&answer=116447
thanks foe the tip, i was doing things the hard way!