globally turn off opacity/transparency?

[Buck]

Did there used to be a way to globally turn off opacity? I seem to remember doing that at one point a long time ago, but maybe I'm faking that memory.

Is there a way to do this in the render settings?

[hermit.crab]

V-Ray does not have such an option, however, you can set up a Render Layer in which VRayMtls' opacity is overridden to black.