check the way your face (quad is facing).... that is the other thing i can think of.. if the face is in the wrong direction it will render black.. unless u select 2 sided.
but i dont want to do a loop selection...just want to be able to start with a selection of a face and then within that loop pick another face and it then selects all the faces inbetween.
Not sure what I am looking for in the face / vertex normals. Face normals are at a 90* angle, and vertex normals seem to flow with the angle of the edge where faces meet.
if you have access to the sdk the way edges and faces are constructed is in the file c:\..\maxsdk\samples\modifiers\uvwunwrap\TVData.cpp though it ain't pretty :?