dennis-balzer

0 replies · posted

Unity HDRP ies-Profiles behaving like masks instead of bundling the light.

So while we are updating our assets to 2020.2.1f1 HDRP we are working on our settings for light-sources and trying to match real world lighting as much as possible, we noticed odd behaviour on ies-profiles in regards of light intensity values.

So first of all a quick reminder of lumens definition in short:
"The unit of luminous flux. Describes the total amount of visible light that a light source emits in all directions."
https://docs.unity.cn/Packages/com.unity.render-pipelines.high-definition@10.0/manual/IES-Profile.html

If we think about Spot lights in a way that they in reality are actually point lights but the light that is directed to the top and sides is redirected by the reflector shaped as a cone just above the light source, we have to assume means that the light amount will intensify on the floor.

So what Im saying is, a Point Light with 1000 Lumen should be dimmer in the same area where a Spot Light with 1000 Lumen is bundled.

Applying an ies-profile to a Point Light does not show this behaviour though. Instead it just masks off the Light and doesnt redirect/bundle it at all.

What are Your thoughts of this and would You consider this a bug that needs to be fixed?