Hi Richard,

I'm not sure with the subDiv's and Nurbs... but with the polygons you can turn on backculling...

go to "Display"... --> "Custum Polygon Display" (optionbox)...

and then go to the bottom of this menu, and make "Backculling" on... also make sure there is a "marker" in the checkbox "BackCulling" at the second line "vertices"...

regards

Strarup