advise on AA type and unclamped renders

[R2J2]

could you guys rendering to exr tell us about what AA type you use. The problem I'm having is that using DMC as I usually would, gives me sharp and spotted reflections. While using Adaptive subdivision gets rid of that at a cost to the rendering time, because I'm now I've upped the glossy sub-divs.

were an animation studio so I'm am a bit concerned about render times and/or noise with the glossy reflections.

[Paul Oblomov]

Plz post you problem picture

[R2J2]

green dots on a reflective surface. hehe sounds like art
this is default DMC settings, I can reduce the effect but not remove it. obviously with clamp off.

[mike_kennedy]

Saw this with Adaptive AA a lot.
We switched to Adaptive DMC and turned on Sub-pixel color mapping and it helps a lot. Also getting rid of any over brights list in the Vray log window helps.
Turn of the sun if using the vray sun oif you can as well, it can cause issues with glossies.
Cheers
Mike K

[^Lele^]

Turn of the sun if using the vray sun oif you can as well, it can cause issues with glossies.

I think he meant sun VISIBILITY.
Those fireflies look just like the sun doing its own (correct, but undersampled) thing.

[R2J2]

thanks guys but I'm only using VRay lights which have visibility off already. sub-pixel mapping didn't help. the only thing that I had come up with was to use adaptive subdivision (gets rid of the highlights) and up the glossy subdivs to get them back to what DMC would do, unfortunately as expected the render times when right up.

[^Lele^]

now i'm intrigued.

Any chance to see a stripped scene?

[R2J2]

here it is

max file ziped

[^Lele^]

It's your reflection map causing the issue: The submap "Noise" creates bright reflective spots which are tiny, and the DMC does the right thing, really: they're tiny, and very bright, hence the firefly look.

Turn the noise off, fireflies gone.

EDIT: no it's not :P
Turn the lights "Affect Reflections" off, and it sorts it.
The noise trick worked only once, strangely enough, and then stopped working.
What's probably creating the issue is light fixture size: VERY narrow and long, and very bright.
One way around this is to lower the lights intensities (say to something like 5) and use the physcam to expose.
That'll lead to much nicer speculars / reflection spots, nicely antialiased (less HDR range in adjacent pixels).

[R2J2]

thanks for helping us out Lele.
one question on that would be, if I have a lower light value then the dynamic range would also be lower. wouldn't that mean less to work with in post?
I don't like the idea of not using reflections on the lights but I suppose for most gloss ref it wouldn't really matter that much.
I'll have a look at this this afternoon -VRay cam and exr, see what I get.

[^Lele^]

The actual range EXPRESSED by the image would be smaller (say, if before your light was @ 50.0 if seen directly, now it's only at 5.0), but none of the "fine grain" of the float format would be wasted for post work.
There's still so much hidden inside a 32bpc image that monitors can't display, in terms of shades available to a single pixel.
Short answer: no it shouldn't make any difference.

[R2J2]

ok, thanks again for looking into that