Quick answer: Unity baked lighting darker than expected indoors near windows? The skybox isn’t contributing indirect light — Environment Lighting set to a flat color instead of the Skybox.
An interior bakes look pitch-black where light should pour through the window. The sky’s ambient contribution wasn’t baked in.
Environment Lighting Source
Window → Rendering → Lighting → Environment. Source: Skybox / Gradient / Color. Skybox uses the scene’s skybox material for ambient and reflections. Higher Intensity Multiplier brings more skybox energy into the bake.
Skybox Material Quality
Use an HDRI or a properly tone-mapped skybox. A flat color skybox bakes flat — no directional ambient. Procedural sky works but is less detailed than authored HDRIs.
Bake Window Contribution
The skybox is sampled through windows during the indirect bake. If the window has a glass material that scatters, tune it; emissive glass also contributes.
Realtime vs Baked
Baked Global Illumination needs a full bake (Generate Lighting). Realtime GI updates progressively but is heavier per frame. Pick based on platform.
Verifying
Indoor scenes show natural soft light near openings. Color from the sky tints the indirect lighting appropriately.
“Skybox contributes indirect via Environment Lighting. Source = Skybox + Intensity > 0.”
HDRI skyboxes give the most realistic baked lighting — the dynamic range carries through to indirect light, unlike LDR images.