• ← FormatType
• → NotOptionQ

None

WMA link

None

is a setting value for many options.

Plot3D shows the mesh grid between computed points by default. This the Mesh
However, you hide the mesh by setting the Mesh option value to None:

• • Plot3D[{x^2 + y^2, -x^2 - y^2}, {x, -2, 2}, {y, -2, 2}, BoxRatios-> Automatic, Mesh->None]