A distant light is a infinitely far light source. It is generally used to replicate the light effect from the sun.


A distant light in the GafferThree node parameters and in the Viewer.
Visible to Camera
Turn this parameter on to make the sun disk visible in the rendered image background.
Transform
Specifies the translation, rotation and scale applied to the distant light. Only the rotation has an effect when rendering, but adjusting the translation and scale can be useful when manipulating a distant light in the viewport.

The Object tab of a distant light.

The Material tab of a distant light.