Reading the readme file accompanying with q3map2, I noticed the new key for func_group, _rc & _cs, yesterday.
I could guess a little about what it does but it won’t work. :disgust:
There should be no mistyping because I checked 3 times comparing with the readme file.
BTW, even if it worked, it seems to be very complicated for me to manage them across the whole level.
Any suggestion, please?
I have used the _cs key for lamps that casted too much shadows on ceilings
key: _cs
value: 0
—> the func_group having this won’t cast shadows
_rs is similar
I think this feature should be functional in the latest Q3map2
Thank you for your reply with an example usage.
It opened my eyes a bit.
By changing _rc to _rs, it works fine now. 
official readme says _rc though I should have noticed from the key word “receive shadow.” :disgust: