MatID pass comes out textured, what's going on?

[ikercito]

Hi guys

I've just discovered something quite odd. I ran a bunch of renders and saved them in the usual manner. 32bit EXR with all render elements (Cmasking_ID and CGeometry_Zdepth) added automatically as layers to the resulting EXR. I've always worked this way and it's the first time i see the following:

When I reopen the EXRs in Photoshop the MatID pass is textured, instead of being bold and bright colours as usual. There is quite a bit of light/shadow (or albedo?) information in the masks, which makes it impossible to use reliably. I'm attaching an example.

Can anybody help me out? I've re-rendered only the elements in one of the images and saved it straight to TIFF from the VFB and it came out as it should. What went wrong with the EXRs?

[Dionysios.TS]

Don't know the answer to your problem unfortunately but I am having big OpenExr problems since I upgraded to 3ds Max 2017 + last daily builds and I can't use OpenExr anymore!!! -.-

Dionysios -

[maru]

This is the second time I see something like this, and it looks a bit as if sampling focus mask was baked into the image. Unfortunately the other user manage to fix the problem randomly, or it just disappeared (I do not remember) so we did not have a chance to take a closer look at it. Could you send us any scene where this happens?

One solution worth trying would be removing all render elements from the list, and the re-adding them again. It is known to help in many strange cases and it looks like it's a 3ds Max thing.

[ikercito]

Thanks guys,

Dionysios.TS: I'm on 2014 and only started seeing this problem since updating to Corona 1.4

Maru: I'm re-rendering one of the scenes to replicate the problem. If it happens again I'll be sending the scene for debugging (looks like it's not happening anymore)

So I guess I'm going to have to render all the masks again, dammit... :(

[maru]

You can use the "render only masks" option for this (render setup > scene > render overrides). This will greatly speed up rendering!

[Dionysios.TS]

Thanks ikercito but the problem I heve is different but always related on OpenEXR: https://forum.corona-renderer.com/index.php/topic,12623.msg81840.html#msg81840

Don't know yet if is the new daily build or 3ds Max 2017, I need to check this with the 2016 version of Max at this point.

Thanks,

Dionysios -

[ikercito]

Yeah Maru, just rendered the elements, I love that feature.

Long time ago I learned (the hard way) rendering the elements individually helps with RAM usage a lot! Glad we have that feature.

BTW, I've had this same problem repeated a few times now, but it seems to come and go randomly. Once I try to recreate it it's usually gone... But never had it while rendering elements individually, so at least I know the safe option.

If it persists and I can recreate it i'll send in the scene. Thx.