Using the native LDraw parts (meaning non-LGEO) to render a model, I found out that part Exhaust Pipe with Pin and Flat Tip (14682.dat) appears to be hollow when rendered. The part itself appears to work just fine and looks normal inside LDCad and the LDViewer. It might be a matter of flipping the polygon 180º, but I don't know how to do that (yet).
Admins, please move this to a more appropriate place if needed, thanks.
Admins, please move this to a more appropriate place if needed, thanks.