Troubleshoot global illumination doesn’t work
or looks incorrect
The
problem is any of the following:
Global
illumination is not turned on. If you did not use the global illumination
presets (see
Render with global illumination),
it might be turned off.
Raytracing is
not turned on. If you did not use the global illumination presets
(see
Render with global illumination),
it might be turned off.
If
caustics is not turned on, too many photons may have migrated from the
global illumination photon map to the caustics photon map. For more information,
see
GI photon maps vs. caustic photon maps.