Hi, i would like to know if a shadow can be generated without using light, but only objects that emit photon !
well, a shadow is merely lack of light, so the answer is yes of course, but the nature of radiosity produces soft shadows, and weak shadows in confined light spaces.
as long as I know, shadow is generated from at least one light,,
with global illumination, you definitely need light to emit photon,
final gathering is quite simple, but you still need at least one light, even with intensity: 0