3. How to average vertex normals
Uniform, area-weighted and angle-weighted.
Triangles: · Drag the view to turn it.
- A Uniform: every surrounding triangle counts the same. The result depends on how the surface is split into triangles.
- B Area-weighted: bigger triangles count more. On the beveled box, the large faces stay flat.
- C Angle-weighted: each triangle counts by its corner angle at the vertex. However a flat area is split, the angles add up to the same total, so the split does not matter.
- The cylinder caps are split as a fan from one vertex. With A, the shading bends around that vertex; with C it does not.