Vray next; cryptomatte jagged edges with no lights

[asin_asinn]

Hello, we have issue with cryptomatte, (either it using material ID / obj / node name) the render result will be jagged if no lights visible in render layer, we need to disable the lights to optimize render time, so it will be render black.

render setting as follow
how to build the issue, create any basic geometry, that overlap each other put vray material on it, , disable the light and default light, put cryptomatte and render

maya 2018.6 windows 8, vray next maya update 2.2 v4.30.02 april 24 2020



Cheers

[seandunderdale]

Im working with a guy who worked at the studio where they developed cryptomatte. I had jaggy issues lately, and his response was to set min and max subdivs the same. I used 5min / 5 max, and it seemed to work. At least the comp guy said it improved the quality.

[dougWilkinson]

we ususally override off GI, shadows and add only one light when re render "info" passes and crypto. the reason we do this is because if you render black you get jaggies... There needs to be some contrast in the image or else vray will think there's no need for any more than one sample.
the min/max that seandunderdale mentioned should give you the same results more or less. this problem isn't specific to vray tho, and its more about adaptive rendering in general.

[Buck]

we ususally override off GI, shadows and add only one light when re render "info" passes and crypto. the reason we do this is because if you render black you get jaggies... There needs to be some contrast in the image or else vray will think there's no need for any more than one sample.
the min/max that seandunderdale mentioned should give you the same results more or less. this problem isn't specific to vray tho, and its more about adaptive rendering in general.

agreed. And you can also limit the global material trace bounces too, to get render times down for this utility pass.

[SonyBoy]

Yeah it's really not necessary to have ZERO lights on a pass. You might save a few nanoseconds per frame by having none, over having enough lights to completely clean up this issue.

[seandunderdale]

Ive found no lights to be a lot quicker. If Im doing an 8k+ car interior with leathers in bump shaders and complex suede materials, no lights + high min samples really hammers through a utilitiy pass containing a crypto. It chugs if it has to render off all those textures.

[Buck]

Ive found no lights to be a lot quicker. If Im doing an 8k+ car interior with leathers in bump shaders and complex suede materials, no lights + high min samples really hammers through a utilitiy pass containing a crypto. It chugs if it has to render off all those textures.

if you're just trying to get a crypto output, and the textures are chugging it, you can globally turn off textures.

[SonyBoy]

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[SonyBoy]

Ive found no lights to be a lot quicker. If Im doing an 8k+ car interior with leathers in bump shaders and complex suede materials, no lights + high min samples really hammers through a utilitiy pass containing a crypto. It chugs if it has to render off all those textures.

I'm not suggesting doing a full beauty pass, and you can turn off all glossy effects, SSS and GI. I'm talking about the difference between rendering a pass with and without lights, assuming all these other obvious optimizations are also done.

[asin_asinn]

the thing is this is for separate in character animation, that we need render all BG, char, shadow separatly and 1 more pass for full cryptomatte, because some char may intersect with the set, etc, ofcourse we already did test with glossy reflection etc off, but with fix sampling the render time still not change that much vs with 1 light no shadow.