Nice plugin. It does work to get SketchUp Free models into Unity3D. At work I have SketchUp Pro with good FBX export, but at home, for the kids, I am learning them to use the free version of SketchUp. This is a good script, although with some models there are waaay to many materials. I assume that the UV mapping is the culprit. But I can not complain, as this was a model from the 3D Warehouse.

Minor improvement:

On line 54 you call the "openpanel" method when exporting. This should be "savepanel", so the user gets the correct dialog displayed. Still works on Windows but not on OSX, where you need to point to an already existing file.

Also, the default "." file location could be replaced with ENV['USER'] or ENV['HOME'] or preferably the current file folder, as to make it more convenient. With 'USER' it works much better for me on OSX.

(I refer to the unscrambled file, obviously, not the compacted one -- maybe the reason why people think it is a binary file)