I guess you're using 3dsmax? What does it look like when you turn on backface culling? Select your object, right click choose object properties, check on backface culling. If the black areas turn see-thru then you need to flip those polys. You can try resetting xform. Utilities Tab Reset Xform Reset selected. You can also…
Thanks for the replies - I appreciate it. I've never used the normal modifyer, but I tried it and it had no effect. Backface culling did not produce the phenomenon you describe. I might have noticed if the polys were turned the wrong direction as I keep shaded faces turned on most of the time (they turn red when you select…