@escapeartist said:

I thought I'd give this a try and see what happens. Unfortunately, it leaves a more complex model full of missing faces and materials, not quite as badly as the obj exporter.rb that has been floating around or a while (I can't get it to work at all).

What still works best is to extract the .dae from a .kmz and import that to Blender, and you can export from there into the .ase or whatever other format with a plugin; though I must say it imports quite a mess of triangulated faces, and if you want quads you're out of luck.

From my experience on importing Sketchup models to CE2 via collada, the problem with glitches on the models come from exporting an untextured model. This can be solved simply by applying a texture to every visible face of the model, easily done if all its faces are connected, you press shift + LMP while applying a texture and all the faces will be textured. After that there should be no problems.