| | The winding order of a facet is simply the order in which its vertices are declared.
The winding order is generally used to determine a facet's normal. There are two winding orders. The most common, right-handed winding order declares vertices in a counterclockwise, or widdershins order. If you hold up your right hand, make a fist and stick out your thumb, you can see a simplified demonstration of this winding order (which is why it's called 'right-handed'). Your fingers wil curl in a counterclockwise manner and your out-thrust thumb will point in the direction of the normal thus created.
Left-handed winding order is simply a reversal, though it's used by significantly fewer programs than the right-handed order.
Poser and the Wavefront Object format both use a right-handed winding order.
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