This most likely has already been asked, but here goes.
Im rendering some hair, generated from the scalp of a basic head geo. If i just render the hair with the head invisible, i can see through to the back face hair (that should be occluded by the head.)
I'd like to render the hair, with an alpha, ....where the head object would occlude the 'back faced' hair. The head geo would delete from the hair alpha where it is in front of it.
any help appreciated M
holdout shader was the answer for me