Cinema 4D Tip: Cinema 4D: Export Multi‑Layer OpenEXR for AOV‑Driven ACES/OCIO Compositing

Quick tip: export OpenEXR as a single, multi‑layer file to keep comps flexible, organized, and space‑efficient.

Why it matters

• OpenEXR stores high dynamic range data in linear color, ideal for ACES/OCIO pipelines.
• One file per frame with all AOVs/passes makes handoffs to compositing apps reliable.
• Modern compression keeps sizes manageable without sacrificing fidelity.

Set up in Cinema 4D

• Project color management:
  • Project Settings › Color Management: enable Linear Workflow or set Rendering Space to ACEScg if you’re using OCIO.
  • Keep tone mapping/display transforms for the viewer only—do not bake them into renders.
• Render Settings › Save:
  • Beauty Image: OpenEXR, 32‑bit float for maximum range.
  • Enable Multi‑Pass (Standard/Physical) or configure AOVs (Redshift/Octane/Arnold).
  • Format for passes: OpenEXR (Multi‑Layer) so all passes write into a single file per frame.
  • Compression: ZIP or PIZ for lossless balance; consider DWAA/DWAB only if your renderer supports it and you’ve tested your comp tools.
• Which layers to include:
  • Beauty/Combined plus Diffuse, Reflection, Refraction, Emission, SSS, Light Groups for relighting.
  • Utility passes: Cryptomatte (for fast, artifact‑free selections), Object Buffers (fallback), Position/World, Normal, Z‑Depth, Motion Vector.
  • Keep Z‑Depth and utility passes unclamped; prefer 32‑bit for depth and position to avoid banding and precision loss.
• Naming and automation:
  • Use render tokens (e.g., $take_$camera_$prj_$frame) to keep output consistent across variations.
  • Render Queue/Team Render: confirm shared paths and bake simulations/caches to avoid mismatches.

Compositing workflow

• After Effects: ProEXR reads multi‑layer EXR natively; import as “Footage” to access all layers. Set the project to 32‑bpc, linear, and apply ACES/OCIO display transforms in your view, not on the data.
• Nuke/Fusion/Resolve: EXR layers/AOVs appear as channels; verify pass names and bit depths. Keep Cryptomatte lossless and in float.

Quality and size tips

• Avoid lossy compression on mattes, vectors, and depth (Cryptomatte requires lossless ZIP/ZIPS or PIZ).
• Half‑float (16‑bit) can be fine for beauty in some pipelines; test before switching from 32‑bit.
• Disable clamping and do not bake display LUTs into renders; apply in comp.
• For test iterations, render only key AOVs; for finals, include the full set needed by the compositor.

Troubleshooting checklist

• Banding in depth? Switch that pass to 32‑bit and confirm linear workflow.
• Broken mattes? Verify Cryptomatte is float with lossless compression and consistent ID sources.
• Unexpected brightness shifts? Remove baked color transforms and ensure the comp app uses the same OCIO config/ACES setup as Cinema 4D.

Looking to standardize your EXR pipeline or upgrade render tools? Explore Cinema 4D, renderers, and training resources at NOVEDGE. For licensing advice and bundle options, reach out to the NOVEDGE team.

You can find all the Cinema 4D products on the NOVEDGE web site at this page.