Cryptomatte rendering

[remKa]

Hello Paride,

Is there a way to render exclusively a cryptomatte pass sequence without calculating anything else ?

[paride4331]

Hi remKa,
Unfortunately, it's not possible to render the Cryptomatte as a separate pass. If you need to generate it separately because it wasn't enabled during the original render, there are a few things you can do to reduce the render time. Set the render mode to Direct Lighting and GI to None. Direct Lighting requires significantly fewer samples than the other kernels, especially when GI is set to None or AO. You can also reduce max samples. Avoid going too low, as it may introduce artifacts as it can produce noisy or incomplete matte edges. Disable Adaptive Sampling, disable the Denoiser. Enable only the Cryptomatte AOV.
Regards
Paride

[remKa]

Hello Paride, thanks for your reply, this is what I did but could you explain why it's not possible to render cryptomatte pass with the info channel kernel for exemple ? It would be very handy

[paride4331]

Hi remka,
That's because Cryptomatte is generated using the same rendering process as the beauty pass. It's not like an Object Layer, which can be rendered independently. If all you need is a simple mask, though, an Object Layer might be a better option. You can generate the masks you need in just a matter of seconds.
Regards
Paride

[remKa]

I got it, thanks Paride