Ahh.. usually.. only one side of a face is visible and the other side is invisible. I think it use to go by following the vertices around in a clockwise direction, that side would be the visible side. While editing your model in Blender, you can make the surface normals visible. There's an option button availble. It creates a blue line extending out from the visible side of a face. With this on, you can tell if all your faces are pointing in the right direction. Sometimes, when you model something in pieces, and stick it together, some faces end up pointing towards the inside of your model. This is visible when you see 'black' seem lines along some edges of your model. Going to edit mode, selecting all the vertices and pressing "CTRL-N" will flip all normals to the outside (Usually). If your model gets complex, this may not work (I've had problems with this in the past). You can select individual faces and flip normals one at a time if need be. I'm not sure, but having the object 'center' in the correct place, may affect the 'Flipping of vertex' normals. Have a great day everyone.

Reddog9
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