7.5.5 Radiosity without conventional lighting

From [pov:4.1.3]:
You can also leave out all light sources and have pure radiosity lighting. The situation then is similar to a cloudy day outside, when the light comes from no specific direction but from the whole sky.

Figure: Radiosity without light sources

See also
$\cdot$        [pov:4.1.4]Normals and Radiosity
$\cdot$        [pov:4.1.5]Performance considerations