Scene became unusually dark after baking

[steady cosmos]

Originally, there was only directional light and the indoor was quite bright.

Then I added an Area light and baked it but after that, I could see baked light but overall room got very dark.

I disabled Area Light but it's still dark. Not sure what changed.

Maybe something got baked incorrectly and maybe I need to fix it or remove it but I'm not sure how.

Maybe it's related to cache?

[stone valley]

It's clear baked data
Not GI cache

GI cache is only used by the editor internally

Darkness seems unlikely to be related to the area light
More likely you changed something else in environment lighting settings, the scene objects or in light baking settings

[steady cosmos]

I'm sure I didn't change any object in the scene. What I did was add some lights including one area light and baked it. (Ignore those other spot lights, that are I added only later to troubleshoot).

Yeah area light is not the cause, but something happened right after I clicked Generate Lighting first time.

How can I clear baked data?

[stone valley]

Is my picture not showing where the "clear baked data" option is?

If you never generated lighting before, then you'd only be seeing the results of your current settings and setup now

[steady cosmos]

TBH, after baking, it seems "natural", the scene should be dark. But I wonder why it felt like there were already lights inside before baking.

I have an idea. I think I have a backup. I'd repeat same again to see if same happens again.

[stone valley]

Before baking all lights are rendered as realtime so you get some preview of their lighting
And before baking the scene uses global environmental lighting and reflections that are not occluded by any walls but illuminate everything evenly

[steady cosmos]

Oh. Couldn't everything be reset to before baking then? I cleared baked data but it made no difference.

[stone valley]

I don't know what "before baking" was like in your case

The ambient light probes are also handled by the same button that does light baking

So it's possible you had temporary (outdated) environmental light probes before shining some light into the scene, and deleting baked light cache reset them to pure black

Or actually not outdated, considering your sky has some lighting

You can generate just the ambient light by unchecking Baked Global Illumination (as well as Realtime Global Illumination) and then Generating

That gives you the correct "realtime" scene lighting

[steady cosmos]

I'm trying to setup original backup.

I'll show you soon

[steady cosmos]

Here is original setup. (Ignore the pink objects): As you see, there's only directional light and room is bright. Also, I don't see a specific sunlight entering from windows, inside the room like I could see after first baking.

After first baking, I seem to get sunlight only through window and lights only a few walls in window/rectangle shape (shown in older screenshots).

Now I don't understand it's normal or there's some glitch by default.

When there's no light inside, room should be quite dark?

[stone valley]

This is expected

The ambient light and reflections are coming from temporary probes

Generated from the sky by the editor

If you clear baked lighting now, it resets those probes to black

The scene lighting is applied evenly because there is no occlusion information to use in any form
The floor has no way to know it's occluded from the sky's light by walls

That's what Global Illumination systems are for

[steady cosmos]

OK. So this is not ideal right? I'd have to setup it manually to fix it? Like you said clearing baked lighting.

[stone valley]

I don't know what result you are expecting

If you disable baked (and realtime) GI as mentioned and then Generate, the ambient and reflection probes update to get correct lighting from your current sky material

But the light from the sky won't be occluded indoors

Maybe you don't mind that because now you can see indoors

But if you want realistic occlusion you will have to bake lightmaps or other type of GI

[steady cosmos]

These checkboxes? These are default settings when I create a New Lighting Settings.

[steady cosmos]

That is what's bugging me. So I'd get a bright room without lights without indoor lights? That's not normal?

I want natural behavior. Like light should only make some bright spots on walls in window shape like in real life.

[stone valley]

What I'm referring to yes

[stone valley]

Then you do need baked GI

This includes light probes and reflection probes in the scene where applicable

As well as your directional light to be Baked or Mixed for its light to softly bounce in the room

Also important to follow every step required for baked lightmapping
meshes need to be set as GI contributors/receivers, and they need lightmap UV generation enabled if they're GI receivers

[steady cosmos]

Okay that indeed restored that thing I was talking about. Room is brighter with no lights.

But the light from the sky won't be occluded indoors

So it's not occluded now?

[stone valley]

Indeed
The lighting indoors is accurate to the sky outdoors
But every surface is lit as if it's alone in the open

And you can see the sky reflected on the metal lampshade rather than the room, because of no reflection probes
You can use reflection probes without baked GI though, so reflections can be occluded

[steady cosmos]

I guess I understood it correctly. To test, I added a shiny/smooth sphere in corner of room and upper half seems bright. Maybe that's sky that's being reflected. Although I don't see the sun in the reflection. Sun is visible when sphere is near window (so it's directly in front of sun).

And that looks fake.

So I guess I'd go with GI option checked.

Also URP doesn't support realtime GI so baked GI is needed.

I dont' know why realtime GI option is given here when URP doesn't support it. It makes the room a little darker but reflection problem is still there.

[stone valley]

That's the sky
Sun is not visible in reflection because it's realtime and it's occluded by realtime shadows

[stone valley]

Why do you say it isn't supported?

[steady cosmos]

I read this in some tutorial:

URP allows realistic lighting, but has URP-specific controls, a Universal Additional Light Data component, and does not support Realtime Global Illumination.

[stone valley]

Some?

[steady cosmos]

I'll show you

[stone valley]

Works in 6.0 at least

But you need to be aware of what kind of system it is
"Realtime" GI is not quite "realtime"

[steady cosmos]

Okay I read it here: https://learn.unity.com/pathway/creative-core/unit/lighting/tutorial/get-started-with-lighting-in-unity?version=6.0

The Realtime Global Illumination system includes:

Lightmapping: This global illumination system uses a deprecated lightmapper called the Enlighten Lightmapper.
Light Probes: Light Probes have some additional functionality in this global illumination system.
The Universal Render Pipeline (URP), which the Creative Core pathway uses, does not support the Realtime Global Illumination system.

You can search those words in that page to jump to that section

After that I'm assuming it only supports baking.

[stone valley]

Probably an error, or they're being very proactive
They tried to deprecate Realtime GI once already, then extended it up to I believe version which corresponds to Unity 7
Maybe 6.4 or 6.3 are dropping support already
But I have it working right now in 6.0 URP

we will continue to support Enlighten Real-time GI. Our team will maintain Enlighten as-is, without adding any new features, until Unity 2024 LTS ends
2024 LTS is 6.0 I think

[steady cosmos]

But now I see Enlighten is deprecated. How about the "Light probes" GI it's talking about? Is it also GI?

[stone valley]

(6.0 is what you really should be using anyway because newer versions are so buggy)

[steady cosmos]

I'm using 6.0 LTS

[stone valley]

Enlighten realtime GI updates light probes in realtime
Unless you're referring to some other section

Enlighten likely will be replaced by some APV probe based realtime GI system in the future, but we don't yet have any information on that

Both baked and realtime GI do need light probes and reflection probes to work correctly though

[steady cosmos]

I know only the "light probe group", which helps to light up non-static objects even in baked lights. I'm not sure this is the same light probe they're talking about.

[stone valley]

It is

Also for lighting static non-lightmapped objects (aka GI contributors) to save lightmap space and to avoid geometry that's problematic for lightmapping

Important to note that Realtime GI is also a "baked lightmap" system
Or "precomputed" as they choose to call it to lessen the confusion a bit

It has to generate a different set of lightmaps for all GI receiver mesh renderers, representing how they "could be" lit rather than how they are lit like ordinary lightmaps would

Which is why it's a "static" lighting system
Light sources can be dynamic though

[steady cosmos]

I'm not sure what Realtime GI they're going to add in URP in future. Since current system is deprecated.

It must be something new

Or maybe enhanced

[stone valley]

Well, fingers crossed they are sure at this point

They weren't ready to reveal any details like a year or two ago when they announced the deprecation of Enlighten realtime GI, and still haven't

So I think there's a real chance removal of Enlighten will be delayed still

But do you need realtime GI in this case?

Whichever GI system you go with they have their own learning curve

[steady cosmos]

I'm just following the tutorial instructions. They didn't direct me to turn on realtime GI. Only the Baked Indirect option so I'll follow that only for now.

Instead Baked GI. But yeah the sky is still reflected in that sphere. So to fix it, I need reflection probes right?

[stone valley]

Yes

[steady cosmos]

Okay. Cool thank you so much.

[stone valley]

And meshes need to be Reflection Probe static

And lights too

[steady cosmos]

Do you mean objects need to be marked static? Lights are already static that I want to bake.

[stone valley]

There are many types of "static", as it's a dropdown button

[steady cosmos]

Ah

I just checked it's already checked

[stone valley]

Light static flags I don't think has any effect
But the Mode being baked/realtime/mixed

[steady cosmos]

Yeah likely