IssueWhen you apply a Use Background shader to a surface, the Physical Sun does not cast shadows on the surface.
SolutionTo cast the shadows, please do the following:
- Assign the Use Background shader to a surface.
- In the Attribute Editor for the Use Background shader, turn off reflection.
- Create a new Directional Light. You won't get the shadows with the default sky sun light. Put the new Directional Light above the original sun light and match the rotation of the original sun light.
- In the Attribute Editor for the new Directional Light, set the intensity to .3 and turn on ray traced shadows.
- Duplicate the new Directional Light, set its intensity to -.3, and turn off ray trace shadows.
The two directional lights cancel each other out, so that the default sun light controls the amount of light in the scene.