The direction perpendicular to the surface at the vertex position.
This attribute is optional but plays an important role, for example, in lighting calculations.
Normals are commonly represented using the Vector3 format, which consists of three 32-bit floating-point values, resulting in 12 bytes per vertex. If vertex compression is applied to this attribute, each component is compressed to 16-bit floating point values, reducing the total to 6 bytes per vertex.
This attribute corresponds to the NORMAL semantic in the HLSL shading language.
You can access vertex normals using methods such as Mesh.GetNormals and Mesh.SetNormals.
For more information, refer to mesh vertex data.