Is it possible to upload a custom background in CC3?  In the CC3 side all I see is Atmosphere and IBL to effect the backgrounds:
84% of original size (was 602x738) - Click to enlarge
The Iray plugin doesn't seem to have any impact on the background either. And, if I missed this somewhere in the online Reallusion manual, just send me the link - no need to give a long answer. Maybe I just wasn't Google searching the right term.