Mirrored glossy reflections trouble


In short: glossy reflections don’t get reflected in plain mirrors, setting the mirror depth to zero is an imperfect solution.

Long story: this is a case of extreme glossiness you don’t get every day in a project, but there it was: I was working on an elevator interior and had a lot of glossy reflections recreating brushed stainless steel + a mirror wall  = all that was reflected in the mirror was wrong because the blur was gone, all reflections were clear. So BI doesn’t reflect the glossiness.
I understand this is not exactly a bug, more of a BI limitation and have no idea if it will be improved. As Cycles is getting all the attention now, BI might not get many improvements soon or ever. But until I find out whether Cycles will work for my projects as nicely as BI does, I try to find fixes and workarounds….

So what worked in this particular project – though I’m not sure it will cover every variation of this problem – was setting the depth to zero in the mirror material settings. So this killed the secondary reflection completely which is not ideal; the stainless steel in the reflection does not look too great, but at least the weirdness of having unexpected reflections showing up disappeared.

I also separated the mirror in a render layer and used the compositor to fade it a bit with a pinch of blur but I’m still not very good with compositor tricks so probably this could be done better.

Have you stumbled on this before?

  • Ray Tungsteen

    Quite a serious limitation! It’s the same in 2.49… but in Yafaray it works correctly.

    The only workaround I can think of for 2.5+ is blurring an object-masked node, I guess it would be quite messy, haven’t tried it.

    I hope you arrive at a good solution for this project.

  • Oana

    Hi Ray! Yes, I tried something like that but I haven’t been using the Compositor for long so I’m not very skilled in special fixes like this. I’m not sure there is much to do in this case, my attempts to blur the mirror just made it more unrealistic. Fortunately this project had 16 variants and only two showed this problem, I went for the 0 depth approach and the client didn’t really notice as the interior of the elevator looks ok. Maybe Cycles handles this better, but here I had 21 different renders to put together in short time so I couldn’t dream of switching from BI…