Debugging Metallic materials being pitch black

[tidal mirage]

Hello,

First things first, my current lighting settings:

• Most of the scene is using Baked or Mixed lighting
• I have Reflection Probes placed (as you can see on the screenshot)
• I am using Adaptive Probe Volumes
• I do not have any global directional light

You can see my lighting settings below on the screenshots.

Still, metallic materials in my scene appear nearly pitch-black, which to me looks quite unusual, though I am not sure if it is expected behaviour or not. I tried looking into baking specular lighting into the reflection probes using the trick with placing emissive spheres are the positions of the lights, but that still didn't get me the right results.

If there are any other settings I should provide, let me know.

Looking at the reflection probe, I am confused as to why the metallic material still doesn't retain nearly anything and looks this dark. I'm under the impression it might be just some incorrect setting of the scene, so I'd be very thankful if anyone could point me in the right direction.

For completeness, here are the APVs and the settings of the light (changing it to Mixed/Realtime of course helps, but I wouldn't expect metallic materials to be this dark at all).

[raven crescent]

Metallic materials do not receive any diffuse light. They are only lit up by specular lighting

without bright light in the reflection probe, it's going to be quite dark

(the albedo is also pretty dark)

You mentioned that you tried adding extra specular highlighting to the reflection probes

do you have an example with that being done?

[raven crescent]

(well, in practice, you get a tiny bit of color)

[tidal mirage]

Thank you. So this is expected behaviour then, and I have to rely on Mixed or Realtime lights?

For the specular refelections, I used this project as a base:
https://github.com/zulubo/SpecularProbes

Refactored it slightly, but the gist is the same. It worked somewhat, though understandably at the same time it made the level glossier (similar to just increasing the Reflection Probe intensity), so I ended up not using it.

[raven crescent]

If you want to use purely baked lighting, then your reflection probes are going to need to correctly capture the lights

I like to do a lot of my lighting with emissive materials

notably, I do not see a meaningful source of light in that room – you have a point light on its own

Try replacing it with an emissive sphere (ideally, placed on the ceiling) and seeing how the reflections change

a light source in the center of the room is going to be very difficult to capture with a reflection probe

notably, if you use Box Projection, the probe expects the light to be coming from an edge of the box

so an emissive object in the center of the room would be very confusing

it'd act more like a light stuck onto a wall

[tidal mirage]

Thank you very much, that seems to be it. Not using the box projection appears to make it look better to me - I assume I have to be very strict about the room having box shape when using it, correct?

In that case this is the only way (apart from mixed/realtime lighting) to have at least some color on the metallic materials when using baked?

One thing I find pretty strange is the material around the metallic is oddly colored as well - the lights have a slight blue tint to them, but the material appears still oddly colored in blue.

On another scene that uses a realtime directional lighting, it looks correctly black, which makes me wonder whether there isn't still something wrong with the lighting settings on the mostly baked-lighting map.

[subtle zephyr]

I recommend testing the lighting in different parts of the level by creating two capsules, one with a fully metallic and fully or almost fully smooth material, the other with nonmetallic fully rough material, both with fully white color

The metallic one in particular is useful for showing the actual effect of reflection probes and specular from mixed/realtime lights at its location

[subtle zephyr]

Important to note that this workflow with specular probes and reflection probes in general isn't really about glossiness or even appearance, but correctness
The initial issue is that there's a mismatch between diffuse and specular lighting for Baked type lights, which these aim to fix
Without specular probes or anything else as a physical light source to be captured by probes, specular lighting will not match the diffuse from light probes
Increasing reflection intensity will not address this issue

[raven crescent]

any source of light needs to correspond to a surface that could be emitting that light

(or be artificially inserted into the reflection probe)