@Mugen87 is it because that implicit pmrem thing driving the size down to 256 pixels? how to increase the size then, iirc there was resizeable pmrem pr
You don’t have the possibility to exactly set the size of the PMREM. Previously it was fixed, now it is derived from the given environment map. However, the size might not be sufficient to produce a result that makes the reflection comparable with an “ordinary” cube map.