I had previously noticed that the Google Sketchup STL import plugins were very hit or miss.  They probably only imported fully about 60% of the time – with more failures on complex models.  I’ve just discovered a little trick that helps tremendously.

When you are importing, you are given a several different measurement options.  I have been choosing millimeter by default.  But, if that fails to import the entire model, try again using a different measurement!  I just imported a hugely complex model by trying millimeters, centimeters, and finally meters.