If you place a PointLight inside of the cube, the cube won’t be lighted from inside.
Workarround 1: use different light e.g. HemisphericLight
Workarround 2: use several PointLights outside of the cube: if you point the light on a cube from outside, it will light also from inside (actually this is also a bug)
I believe it’s because the normals are on the outside only. I suppose having them in the inside or double sided should solve the problem, doesn’t it?
Indeed, the normals are pointing to the outside. If you want the lighting to also work inside the cube, you can set the
twoSidedLighting property of the material: