How to plot a 3D illuminated surface?

If I know the distance from the light source to the surface, the angle of the light source (120 deg), the value of the luminous flux in Watts (9 Watt) and the surface area that we are illuminating (100 cm^2), how to build a similar surface indicating the change in illumination from the center of the surface to its edges?

Answer 1

[BhaTTa]

Please refer to: https://www.mathworks.com/help/matlab/creating_plots/lighting-overview.html