Whether using a loaded image for reflection, illumination via Global Illumination or as a background image, the Compositing tag offers numerous settings with which this image can be affected. Simply assign your Sky object or sphere a Compositing tag (
As you can see in the image below, parameters such as Seen by Camera and Seen by Reflection that affect object visibility can be enabled or disabled. You can also easily adjust shadow casting and receiving parameters using this tag.
If you disable the Default Light option in the Render Setting’s Option menu you can observe the reflective effect independently from the illumination of the Default light.
Simulating reflection prior to setting up lighting helps us avoid adding light objects unnecessarily in areas where reflection is already intense. Strictly speaking, the reflections simply consist of light reflected from the object’s environment.