The Open EXR Workflow

What is an EXR?

OpenEXR, or EXR for short, is a file type used to contain multiple passes of the same scene. Instead of exporting out to a PNG sequence and baking all of the components into one frame, an EXR file creates multiple passes (selected by you) of the same shot, and each of these can then be edited independantly, meaning you can continue to tweak after you’re done rendering.

This video from ActionVFX explains it well and shows the Cinema4D to After Effects workflow.

The workflow

Create a scene in C4D
Export as EXR image sequence
Import as EXR image sequence into AE
In AE use the EXtractoR effect to turn the sequence into each pass
You can then edit each pass separately

Why use it?

OpenEXR is for when you have the models, camera movement and lights set up how you want, and just want to be able to change smaller things like the amount of AO, or the colours of things, or maybe to add mist using the depth pass etc.

It can also be useful because it gives you the alpha channel, so if you are comping you can use the alpha as a mask for any of your After Effects Layers.

Conclusion

OpenEXR file types can sound really complicated and overwhelming at first, but they’re actually really simple and can speed up a workflow. Yes, it does take longer to render however this makes up for its’ self, once its rendered you can make tweaks and pretty much see them in real-time without having to re-render a highly detailed shot.

Bibliography

ActionVFX, 2019. VFX Tutorial – Render EXR Passes Like A Pro | Cinema 4D. [online] YouTube. Available at: <https://www.youtube.com/watch?v=vi_voPrqpbs&feature=youtu.be> [Accessed 17 April 2020].