Vertex normal

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Vertex normals of a dodecahedral mesh.

In the geometry of computer graphics, a vertex normal at a vertex of a polyhedron is the normalized average of the surface normals of the faces that contain that vertex.[1][2] The average can be weighted for example by the area of the face or it can be unweighted.[3][4] Vertex normals are used in Gouraud shading, Phong shading and other lighting models. This produces much smoother results than flat shading; however, without some modifications, it cannot produce a sharp edge.[5]


  1. ^ Henri Gouraud. "Continuous Shading of Curved Surfaces." IEEE Transactions on Computers, C-20(6) : 623--629 (June 1971).
  2. ^ Andrew Glassner, I.6 Building vertex normals from a unstructured polygon list, in Graphics Gems IV, edited by Paul S. Heckber, Morgan Kaufmann, 1994. pp. 60--74
  3. ^ Nelson Max, Weights for Computing Vertex Normals from Facet Normals, Journal of Graphics Tools, Volume 4, Issue 2, 1999 p. 1-6
  4. ^ Grit Thürrner and Charles A. Wüthrich, Computing Vertex Normals from Polygonal Facets. Journal of Graphics Tools, Volume 3, Issue 1, 1998. pp. 43-46
  5. ^ Max Wagner, Generating Vertex Normals,

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