Making sense of cryptomatte usage in third party programs

[txo]

@JeroenBakker

Thanks for the analysis.Be aware that the project isn’t finished and there are other patches that should land to get stuff better. From a developer perspective it is better to use multiple smaller patches

Thanks for replying! I hope the analysis made some kind of sense…
I had seen the patches that you mentioned, but the thing that worried me (and why I made this post) is that the implementation that is being worked in eevee would work the same way as it does through the compositor, which is the less useful when trying to fit it into an Arnold-Nuke centered pipeline.

@JeroenBakker

Somehow/somewhere a mapping needs to be made from the render result meta data and the meta data that is needed when using the file output node. The mapping is needed as the layer names could be totally different.

I completely agree. I was just talking about the cryptomatte in here for conciseness, but indeed there is need for that in general. I actually made a post about it a little while ago, in which I talk a little more generally about the output. And I even think it should be encompassed by an overall design for a more structured renderLayers manager (I think now is kind of all over the place)

@JeroenBakker

The compositor is sometimes ‘mis-used’ as a pipeline integration tool.

The problem, in my opinion, is that there is no way for a flexible output (that can accomodate a studio’s needs regarding custom layer output, naming, etc) other than the compositor. I wouldn’t say it’s a misuse…I use it because I have no other option to render different multilayer exr files per view layer.

@statixvfx

Since our compers are using crypto materials we need to re-render the beauty JUST to get the metadata in the file out panel instead of the using the compositor, landing us additional 20% rendering overhead pr shot for this

Kind of the same happens in my case. If you have many viewlayers (e.g. main chars, secondary chars, some fg elements, and bg), that may not be even an option. You have to rerender every layer from the main output panel, otherwise if you use the “beauty”, the fg elements are overlapping your main chars, those are overlapping the bg and secondary chars, and so on. And then, weird artifacts appear at the borders when tryin to mask them and do any kind of heavy compositing.