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### #ActualJoryRFerrell

Posted 07 March 2013 - 08:53 PM

<p>How do I determine if a the normal for a vertex has been created by ccw ordered verts or cw wound verts? I assign each vert's neighbors to a list in the order they wind around, but it doesn't assign them in a secific clockwise/ccw order consistently. I have just decided to calculate the normal then determine whether the verts are cw, or ccw, and then change the signs of the normal vector components accordingly.</p>
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<p>Some suggested using a secondary vector to compare the angle between the secondary and the generated normal. If greater than 90, or less than, that would tell me if the normal vector is facing the direction I need. But I don't think this works for concave (NOTE: I originally wrote &quot;CONVEX&quot;. I meant &quot;CONCAVE&quot;. :\) shapes (normals can face toward origin, allowing for angles less than 90 degrees when compared with a vector drawn from the origin of object.</p>

### #1JoryRFerrell

Posted 06 March 2013 - 08:58 PM

How do I determine if a the normal for a vertex has been created by ccw ordered verts or cw wound verts? I assign each vert's neighbors to a list in the order they wind around, but it doesn't assign them in a secific clockwise/ccw order consistently. I have just decided to calculate the normal then determine whether the verts are cw, or ccw, and then change the signs of the normal vector components accordingly.

Some suggested using a secondary vector to compare the angle between the secondary and the generated normal. If greater than 90, or less than, that would tell me if the normal vector is facing the direction I need. But I don't think this works for convex shapes (normals can face toward origin, allowing for angles less than 90 degrees when compared with a vector drawn from the origin of object.

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