Question How does HDRP Lighting work?

Let's say i used the HDRP template and probuilder to make a box with flipped normals. Now i would have a room. Delete all the sun and sky objects that were in the hierarchy by default and in theory, i should have a dark room. But, for some reason, the room seems to be lighted up by the sky or by some light source. Any ideas on how I can totally make the room dark?

Also, emission textures don't quite work as intended too, in normal unity, i would see the light flooding the floors and such but here, i dont see anything. Its as if its not even in a room.

 

HRDP uses a default settings volume profile , provided you do not have one in your scene, for eg:

Create a volume profile, and add it to your scene, make sure its global.

Now, turn off everything , and with no visual environment, sky, lighting, it should be dark.

If you have more questions - feel free to msg me on discord. JD#1539

 

Broadly speaking, you have direct light (like your sun, some spotlights, whatever) and indirect light (like the sky environment / a.k.a. ambient light).

In a real-time lighting environment, the interior and exterior of your room will be lit correctly in relation to direct light.

But the interior and exterior will be lit equally by indirect light, and even receive sky reflections inside for smooth surfaces. This is because the ambient lighting system does not understand that your room has an "inside" and an "outside" - it just sees everything as a surface to receive ambient light.

You will need to bake indirect light, or use something like ray-traced ambient occlusion, etc., to create realistic interiors.

 

I got bitten by ground tint in the volumes profiles - light glowing from underneath. Set that to black helped me. My notes are here: https://extra-ordinary.tv/2022/09/25/lighting-tricks-in-unity-hdrp-for-cinematic-effect/