Michael,

Thanks for responding so quickly.

By selecting all in Sketchup then hiding and unhiding and then selecting all again and smoothing I can get the sketchy edges to render.

One other problem is the holes on the test piece aren't rendering the sketchy edges - presumably because the edges are too short for the style but if I select all the short edges that form the circular profiles for the holes and weld (weld.rb) them into polylines, they will render.

Not sure if this is fixable in the export or not?

Simon