FPS drop when Ray Tracing shadows disabled

Hi all,

Yes, it may sound strange, but in a project with Ray Tracing enabled and with a directiona light, if I force to disable ray traced shadows with “r.RayTracing.Shadows 0” (so it changes to “raster” shadows), the performance is less than leaving them enabled. You too?


There are cases where raytraced shadows can be cheaper than cascaded shadow maps. It’s generally when you have a very far CSM draw distance and/or high triangle counts in the shadow mesh(or in the case for default Unreal, the rendermesh).

Yeah it could make sense. Search for one of the Epic official RTX livestreaming (on the Unreal Engine youtube channel), and you will find some interesting explanation for this.