This is documentation for Mathematica 8, which was
based on an earlier version of the Wolfram Language.

# VertexNormals

 VertexNormals is an option for graphics primitives which specifies the normal directions to assign to 3D vertices.
• VertexNormals specifies that vertex i should have effective normal for purposes of shading by simulated lighting.
• The are vectors of the form . Only the directions of these vectors ever matter; the vectors are in effect automatically normalized to unit length.
• VertexNormals->None specifies that no explicit vertex normals are being given, and normal directions should be deduced from the actual coordinates specified for vertices. For point and line-like primitives, no shading based on simulated lighting should be done.
Compute normal vectors using the cross product of edge vectors:
A triangle with normals pointing in the direction :
Using different normals will affect shading:
Specify vertex normals for 3D lines:
Specify vertex normals for 3D points:
Compute normal vectors using the cross product of edge vectors:
 Out[2]=
A triangle with normals pointing in the direction :
 Out[3]=
Using different normals will affect shading:
 Out[4]=
Specify vertex normals for 3D lines:
 Out[5]=
Specify vertex normals for 3D points:
 Out[6]=
 Scope   (2)
Define vertices and face indices of a cylindrical model:
Without surface normals, the shading is constant or flat for each polygon face:
With surface normals, the shading is interpolated or smooth across each polygon face:
Plot functions automatically generate surface normals:
Without surface normals, you get flat or faceted shading:
 Applications   (3)
A function that visualizes the surface normals using lines:
Visualize the normals for some surfaces:
Vary the effective normals used on the surface:
A shaded mesh line object with data from ExampleData:
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