When I started my journey in Unreal Engine, I often heard about PBL (Physically Based Lighting). Everyone talked about how it makes scenes more realistic, but I never really paused to understand what it actually means.

And to be honest — I’m still learning. I’m not great at lighting yet, and I personally think it’s the hardest part of creating a believable environment. But the more I learn about it, the more I realize how important it is.

What is PBL? 👀

Physically Based Lighting (PBL) is an approach that simulates how light behaves in the real world as closely as possible. Instead of faking brightness or guessing values, Unreal Engine uses real-world lighting units so scenes look natural and consistent across projects.

But to understand PBL, we first need to answer:

Measuring Light: The Key Units in Unreal Engine Light can be measured in many ways — candela, lumens, lux, nits, and more. Each unit captures a different property of light.