Why do I need reflection probes to prevent sky light when all light is baked?

Why do I need to painfully place reflection probes to prevent sky reflection? Isn't baking suppose to take care of that for me? This has been a pain point for a long time and I'd like to know why it's a thing.
If I bake lights, isn't sky light baked?

And isn't SSR supposed to help with that? It seems to do the job in built-in but not HDRP.

 

Do you have picture examples? Fallback will fall back to whatever is set in your environment, the sky is default.

 

with probes:

without:




With:


without:


Ignore the weird looking cubes, this sky issue always happens no matter what.
Actually you can see it in action within the HDRP sample, go into the interior level and simply remove a reflection probe, then things will go very wrong. Even though lighting is baked there.

I tried physical sky and HDRI, and both static & dynamic

 

What is in your Volume Profile ?

I'm going to guess here a little.
When you disable light probes the global ambient light probe might be used.
Also are your objects static ? I'm surprised light probes are used at all when you have baked lightmap.

 

Light probes are not used, it's all lightmaps. Light is baked and all the cubes are static & receive baked ligh
It also is the same for the official HDRP sample

 

Lightmaps can store only diffuse lighting (view independent) but in PBR every surface also reflects some light (view dependent specularity). Without probes those reflections are sourced from the global reflection probe generated from the skybox, causing "reflection leaks".

 

I recently got some problems with reflection probes.
So baking reflection probe was using Window->Rendering->Lighting->Environment volume instead of scene volume.
Also Baked reflection ,real time reflection, and custom reflection were like totally different.

Can you set your reflection probe to realtime and see the behavior.

But thinking some more about this it is not exactly your problem

 

Did, similar results. The issue is that I need reflection probes in the first place to get correct lighting after baking, but neto's explanation makes sense.

 

Shouldn't SSR help with that, acting as a replacement for reflection probes? (even if the fact it's screen space can lead to issues with screen corners)

 

Yes, but SSR still needs to fallback to something when it decides it doesn’t have the info it needs, and falling back to the sky color will look like ass. (as opposed to something from a local reflection probe, which will be a lot closer to correct color values)

 

As Neto & AcidArrow above mentioned:
https://docs.unity3d.com/Packages/c...l/Reflection-in-HDRP.html#ReflectionHierarchy

In addition, IIRC HDRP SSR has a quite high "Minimum Smoothness" value set by default.