How do I create high contrast reflections?

Primarily in cycles and EEVEE as a bonus, how do I make high contrast reflections? I want to make my character’s eyes reflect only from very bright emissions and everything else doesn’t reflect. If there was a very bright red light it would reflect red. I mention this as I can’t just use a black and white ramp.

Bottom image is the desired effect.
eye-reflection

I believe that you will make in the compositor, maybe using cryptomatte to separate your reflective material.

Maybe you don’t even need to use the cryptomatte for that if you use the direct pass from glossy.

I’ve been trying all kinds of mixing and matching nodes but I can’t get it to work.

In composite, you say?

Did you activate the glossy direct pass?

I’m trying shading I never used ever compositing. I do not know what to do with that.

And it’s time to turn off the pc for now as it’s getting too hot in the day. I’ll try again tonight.

Well, compositing is not a monster it seams to be at the first glance and the workflow is very similar to the material nodes, once it’s also node based. So, if you are familiar with nodes to work with materials it will be easy for you to deal with the compositor.

I can think of a few things to try. One is do the glossy with a low ior mixed with a transparent node. Second is change the material so it selectively picks which rays are reflected. More specifically I think there is a node where you can pick out the primary rays, the rays straight from the emitter, and non one the secondary diffuse rays, the ones that bounce off a surface. Some combination of those could be good too. Time to play with nodes.

Option 2 would be fake the reflection by putting what looks like a light is being reflected as a texture on the eye. This could be done with a separate mesh so it can be moved around.

Edit: The Light Path node is the one you will want to play with the get the diffuse and rest of the rays.

If you do not want to bake or move around between programs with regular PBR maps, you can simply crank up the Clearcoat. That basically does this. If you place it on a shiny glass like surface, you can reach pretty interesting results. Also turn on sub surface scattering for the color of the eyes. Even inside the Principled, there is a lot to tweak. Additionally, you can add a Glass shader with transparency, but I would simply try the main shader like this

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I believe you are refering to the light path node. That cooud work, but it can also make the material darker than it should. since a good part of the GI is going to disappear with that.

But it deserves a try. Using singular ray visible and disabling diffuse.

For a very low-effort approach, you could try the toon bsdf (Cycles):

The light source is a point light with 3000 W.

The Clearcoat method @AgentTuron suggested is probably the easiest, and fastest way to achieve that.
I did a quick, and dirty test

It looks good IMO. In eyes, everything reflects, not just a point of light, so it seem to be doing the trick. Of course you should be able to tweak the light path, not to see the actual light, if that is in the way. But in real life, it would be seen as well (if you really model an actual lamp or so, you know what I mean). Anyways, I am happy it works.

Also, the model itself looks pretty good by the way, so good luck tweaking it :slight_smile:

I’m not actually doing much with this image, just a test for the OP to show that your advice works great.
The model is from Sketchfab.
I’m having fun with the Photographer add-on :slight_smile:

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“…It looks good IMO. In eyes, everything reflects, not just a point of light…”

This is going completely off topic.
I’m asking to reflect nothing except very bright emitters and to remove the reflection of everything else.

Until we get light linking, as @Calandro mentioned, you have to rely on compositing the desired result. I don’t think it is otherwise possible.

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