The thing is that Raytrace reflections doesn’t take into consideration global illumination as you all can check in 5.3 where shadows on reflections are just plain and bad looking. for your use case that may not be important. but having mirror like reflections that are unreal for other cases is not a great solution either.
to improve your reflections in 5.4 use
r.Lumen.Reflections.DownsampleFactor 0
By default, the value is 2 (in high settings)
and documentary says that it should change to 1 in epic or cinematic but that doesn’t happen i guess from a performance point of view because as you said most projects won’t benefit from this.
this will improve default reflections by a lot but still isn’t enough for mirror like reflections by itself
pair it with
r.Lumen.Reflections.Temporal 0 although this may introduce a little of noise which is reduced a little with
r.Lumen.Reflections.RoughnessFadeLength 1 but not completely
i think is good enough for most cases but check if this works for you.
if i manage to find a better solution i will come back to this.
Note. Remember to increase max reflection bounces accordingly depending on your needs to avoid black reflections from subsequent bounces.
