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I’m working on a small animation/film, I will render the frames out as PNG then sequence them together. How do I use the cryptomatte/render passes feature on this animation because when I add an image strip, all of the passes/cryptomatte are gone. Thanks,

Noobmaster69
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1 Answers1

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Png does not work with cryptomatte, as it requires a 32bit float precision which PNG can not provide. You must use EXR in float32bit !

Blender will save out either a OpenEXR or OpenEXR multilayer. If you want all layers in one EXR file per frame, choose the multipayer option.

If you wish to save out multiple EXR per pass (Diffuse, Specular, Crypto ..) you must do via the Compositor "File Output" Node.

Apparently Blender will not render out multiple passes as EXR unless from inside the compositor. See also this answer here: Save all render passes to EXR image?

Mdkai
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  • Ok thanks, but will the cryptomatte data and render passes (such as mist) stay in the image like the metadata? Will it still stay when I render to a folder then import the images back into blender compositer as an image sequence? – Noobmaster69 Feb 26 '21 at 21:52
  • Yes, it was designed for exactly this purpose ! EXR is a multichannel format that can store arbitrary channels of any sort.

    Keep in mind that cryptomatte can be very memory intensive, as it grows with the possible data shown.

     – Mdkai Feb 26 '21 at 21:55
  • Thank you very much! – Noobmaster69 Feb 26 '21 at 22:00
  • I just rendered a image and exported it as openEXR with RGBA color and full float color depth and the default zip lossless codec, I then add the image in the compositer but I don’t see the render passes/cryptomatte. I don’t get why it is not working. – Noobmaster69 Feb 27 '21 at 04:48
  • If you want to render all passes in one go please use the multilayer exr so all passes will be saved into one file ! i edit my answer to be more clear. – Mdkai Feb 27 '21 at 06:13
  • Thank you for your help! – Noobmaster69 Feb 27 '21 at 07:58