[james4k]

Physically-based rendering has little to do with global illumination, and is only really about the BRDF [1] used for computing the final pixel color based on a number of inputs for that point in space.

[1] https://en.wikipedia.org/wiki/Bidirectional_reflectance_dist...

[MrScruff]

Well it's pretty hard to do PBR outside of a path tracer since energy conservation is a key concept.