[R] Lattice wireframe: How to avoid drawing lines around polygons when using shade=TRUE

[Oliver M. Haynold]

I am using wireframe from the lattice package, with the shade option set 
to TRUE. When I output to PDF or Postscript, a line gets drawn around 
each polygon of my surface which causes ugly Moiré effects and doesn't 
make sense in my application (think the plot of Maunga Whau--gridlines 
don't make sense). This does not happen when I display on the screen--
then I just get the surface as intended.

I have tried everything from playing with trellis.par.set() to changing 
the code of panel.3dwire, but nothing seems to remove these gridlines. 
Any idea would be greatly appreciated.

Best,

	Oliver