[vinkelhake]

Just a heads up - it looks like the "Path Tracing Off" shots have ray tracing disabled as well. In the shots starting at 1:22 (the car and then the plaza), it looks like they just have the base screenspace reflections enabled. Path tracing makes a difference (sometimes big, sometimes small) for diffuse lighting in the game. The kind of reflection seen in those scenes can be had by enabling "normal" ray tracing in the game, which is playable on more systems.

[fracus]

Ray tracing is more intensive than "path tracing". From my understanding, they are the same with the only difference being that "path tracing" does less calculations by only considering a light source's most probable or impactful paths or grouping the rays or something. Neither scene is using "ray tracing".

[jms55]

Ray tracing refers to the act of tracing rays. You can use it for lighting, but also sound, visibility checks for enemy AI, etc.

Path tracing is a specific technique where you ray trace multiple bounces to compute lighting.

In recent games, "ray tracing" often means just using ray tracing for direct light shadows instead of shadow maps, raytraced ambient occlusion instead of screenspace AO, or raytraced 1-bounce of specular indirect lighting instead of screenspace reflections. "Path traced" often means raytraced direct lighting + 1-bounce of indirect lighting + a radiance cache to approximate multiple bounces. No game does _actual_ path tracing because it's prohibitively expensive.

[cubefox]

I believe the "path tracing" you described here is actual path tracing insofar each sample is one "path" rather than one "ray", where a "path" does at least one bounce, which is equivalent to at least two rays per sample. Though I think the "old" path tracing algorithm was indeed very slow, because it sent out samples in random directions, whereas modern path tracing uses the ReSTIR algorithm, which does something called importance sampling, which is a lot faster.

The other significant part is that path tracing is independent of the number of light sources, which isn't the case for some of the classical ray traced effects you mention ("direct shadows" vs path traced direct lighting).

That's at least what I understand of the matter.