How to create clay renders in Corona?
To create clay renders in Corona use the "Mtl. override" option.
It can be found in Render Setup > Scene > General Settings > Render overrides:
Note: by default, the material used as the override will be assigned to all objects in your scene including window glasses, portals or light emitters. To prevent this, use the Preserve... button or the "0 objects excluded" button and pick objects that you do not wish to assign the override material to:
The material used as the override can be very simple:
1. Original scene:
2. Override material is used for all objects in the scene:
3. Two torus knot objects are excluded from the material override:
4. Clay renders are sometimes useful for investigating rendering issues such as persistent noise. Window glass and portals were excluded from overrides to let the light into the room: