Exclude area light from an object

[amineghorab]

Hi,
I can't find a way to exclude the emission of a light on an object
Anyone can suggest me a way to do it?
Thanks

[mitchino]

You need to set a Light Pass ID for your light, then give your object an Octane Object Tag and Switch 'Use Light Pass Mark' on, then de-check the box for the Light Pass ID you gave the light.

It's quite powerful once you get used to it, but It's a clunky method compared to the way it works natively in c4d.

[frankmci]

Be aware that this does not actually prevent all the light rays from a given light illuminating/interacting with the object. It only excludes the direct rays from illuminating the surface. This means that indirect light rays, like reflections and GI Diffuse from the light source still illuminate the object. Also, the objects in question will still cast shadows from the excluded light.

So while this can be useful in some situations, it's probably not at all the sort of light-linking you are used to from other apps and engines.

Edit: here's an example. The top image has the two light sources excluded from all four objects. The bottom image has no light exclusion. To get the kind of light exclusion/light linking most of are familiar with, you probably need to dive into Milan's great OSL RayType experiments.

viewtopic.php?f=87&t=67849&start=10&hilit=raytype