the smoothing was the problem...got it now! thanks!!

Yes, it's unfortunate, but it does make sense. The free version of SketchUp is so powerful that there needs to be some way to distinguish the pro version from the free version or nobody would drop 500 clams for the pro version. For a more in-depth look at the difference between the free version and the pro versions of SketchUp, see the link below: http://www.suwiki.org/suwiki/index.php?title=The_Differences_Between_SketchUp_Pro_and_Google_SketchUp -abe.

If you still want to use a skybox, you could turn down the opacity of the texture to 65%, SU treats anything with less than 70% opacity as clear, so this should let the sun through without eliminating your skybox.

Does this help? I have only modelled the basic blade and twist. You now need to model the leading section so that the cutting edge is sharp. You will find skin.rb on this site under the Ruby section, although it is not really needed for this model. The final twist has been smoothed, so select hidden geometry to see the construction. Kind regards, Bob Auger model.skp