title: How to determine ordering of 3D vertices
body: <p>If I have 5 Vertices in 3D coordinate space how can I determined the ordering of those Vertices. i.e clockwise or anticlockwise.</p>
  
  <p>If I elaborate more on this,</p>
  
  <p>I have a 3D model which consists of set of polygons. Each polygon is collection of vertices and I want to calculate the norm of the polygon surface. To calculate the norm I have to consider the vertices in counter clockwise order . My question is given set of vertices how can I determine whether it is ordered in clockwise or counter clockwise?</p>
  
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  <p>This is for navigation mesh generation where I want to remove the polygons which cannot be walked by the agent. To do so my approach is to calculate the surface norm(perpendicular vector of the polygon) and remove the polygon based on the angle with 2D plane. To calculate the norm I should know in which order points are arranged. So for given set of points in polygon how can I determine the order of the arrangement of points.</p>
  
  <p>Ex. </p>
  
  <p>polygon1 consist of Vertex1 = [-21.847065 -2.492895 19.569759], Vertex2 [-22.279873 1.588395 16.017160], Vertex3 [-17.234818 7.132950 7.453146] these 3 points and how can I determine the order of them</p>