[VMAX-6228] Force Matte objects issues.

[david.anastacio]

Hi,

Looks like the Force Matte objects list is not completly working. Some residual stuff can still be seen in some renders.

In this example, this opbject is used has a Matte object in the ROP, I exposed up a bit to see it better.

RGB:


Alpha:


Looks like this guy needs to be set to 0.0 when you use the Force Matte objects in the ROP.



Best,
David.

[david.anastacio]

Hi again,

Got to bug you, sorry. Can I get a fix for this as soon is possible please?

best,
David.

[Gosho.Genchev]

Hey David,

this parameter is actually already set to 0 in the export:



Any chance you could share a scene with us ? If not, a screenshot of the material/shading network assigned to the geometry in the screenshots above may help to try to figure out what's going on.

Best regards!

[david.anastacio]

Hi Gosho.Genchev, I tested it further, it's not the shaders (tested it with a black shader with no relfection), it's the Aerial Perspective, it's showing up over matte objects.

Best,
David.

[david.anastacio]

I noticed a [VMAX-6228] code was added to the title, so it's safe to assume you guys are on to it?

Best,
David.

[bdancer]

It's safe to assume that the issue is logged into our bug tracker.

[Gosho.Genchev]

Hey David,

Yes, it's a know issue that is already logged in the bug tracker, as Andrei has mentioned above. I didn't answer right away because I was hoping for a workaround, and I can't say for certain when the problem will be fixed.
I've asked colleagues around the office and the suggestion is to use the Matte Shadow / Atmospheric elements together with either Cryptomatte or Multimatte for a Back to Beauty composite. The problem is that the matted geometry is visible in the background and atmosphere elements which are added to the final RGB plane. Comping things back together with a tweak to those two based on the matte geo mask should produce the proper result.

Hope that helps!

[david.anastacio]

Hey David,

Yes, it's a know issue that is already logged in the bug tracker, as Andrei has mentioned above. I didn't answer right away because I was hoping for a workaround, and I can't say for certain when the problem will be fixed.
I've asked colleagues around the office and the suggestion is to use the Matte Shadow / Atmospheric elements together with either Cryptomatte or Multimatte for a Back to Beauty composite. The problem is that the matted geometry is visible in the background and atmosphere elements which are added to the final RGB plane. Comping things back together with a tweak to those two based on the matte geo mask should produce the proper result.

Hope that helps!

Of course workarounds are already in place ou our side to get rid of it, but I would rather not have it there in the first place. For example it screws up the "data Window crop", as it becomes much bigger that it needs and frames are then slower to load in nuke. Also requires a proper multimatte to be set up that econtains all the visible geo of the objects visible to primary rays, since Cryptomattes with motion blur are not perfect. And also the added render time (not much).
Hope you guys can come up with a fix for it rather than leave it as is.

Best,
David.

[david.anastacio]

Hi,

I'm assuming this issue is fixed Gosho.Genchev and bdancer?
Just test in the latest nightly and the issue is not present anymore.

Best,
David.