I'm experimenting with the Octane Falloff Texture, but there does not seem to be an option to base falloff on the angle between a specified light source, the surface normal of the object, and the camera.

The angle between the camera and the surface normal is the "Normal vs. Eye Ray" mode, and the angle between the surface normal and a couple of different vectors is available with the other two nodes, but that's it. And looking around the OctaneRender 2018.1.3 node system for the LightWave plugin, there doesn't seem to be a way to specify that the falloff should be based on the current angle between a specific light source, the surface normal, and the camera.

Or is there, and I'm just missing something blazingly obvious!? (Hey, it's been known to happen. ) My spidey sense tells me that the answer is to plug in... something into the blue "Direction" input node of the Octane Falloff Texture, but I'm stumped what that would be. There doesn't seem to be a node that gives you the coordinates of the light source that's half of the angle equation. So, after fooling around with this for an hour I've come here to let the experts turn me from my foolish ways.

Any idears? Thanks...

EDITED TO ADD: Basically, I'm in search of an alternative to the film settings that can be applied to OctaneRender materials. I'd like to be able to specify exactly what colors I want to see during specular reflection from various angles, instead of endlessly fiddling with film width and IOR to get the colors I'm looking for. Thanks...