That sort of noise at harder to reach spaces for light is pretty persistent, something I battle a bit too. I don't think Corona will beat Vray time for completely clear image if you're comparing Vray's Irradiance Cachce to Path tracing as primary solvers. It's more about the quality Corona will give you given same time. Just try to get interior frame with BruteForce in Vray under 40 minutes being clear ;- ).
Some suggestions for Bump I find compared to Vray is, use filtering if you don't, rather lower value compared to Vray. Looks more like reflection problem to me though.
Hey, Juraj!
I don't think it's fair to compare PT to Brute Force. They work kind of differently, so I guess a more appropriate comparison would be against V-Ray's Light Cache Progressive Path Tracing. At this point, since it can use GPU, it's a lot fast...
Also, my main point testing Corona is to see how it stacks against my current renderer, regardless which method they use. In the end, we all want a clear, decent render in the shortest time possible. ;-)
About the bump thing I mentioned, I'm indeed using filtering... And the same map is applied to reflection, meaning it has no reflection in the grout part whatsoever. Maybe that's the problem?
I'll be testing this scene further in the following days. Right now it's there cooking till tomorrow...