Shading is an option for SurfaceGraphics that specifies whether the surfaces should be shaded.
False, the surface will be white all over. So long as Mesh
True, however, mesh lines will still be drawn.
True, the actual shading used can either be determined by the height, or, when Lighting
True, from simulated illumination.
See the Mathematica book: Section 1.9.7.
See also: HiddenSurface, ClipFill.
Compare the two plots to see the effect of resetting the option.
Evaluate the cells to see the graphics.