1.4.1. Blender 3.4 alpha & OCIO v2-beta.030


Setup Blender 3.40 (alpha) to work with OpenColorIO-Config-ACES 0.3.0 (OCIO V2-Pre-Release)

Just in time for Siggraph there is an update to the new OCIOv2 configs.
Here is the announcement on ACESCentral.com.

I wanted to test the new config in Blender in the same way I did in the past with the OCIO V1 configs. The instructions can be found on the previous page and also here in a shortened version:

  • Download the OpenColorIO-Config-ACES 0.3.0 (Pre-Release) from this link
  • github.com/AcademySoftwareFoundation/OpenColorIO-Config-ACES/releases/tag/v0.3.0
  • This time the download contains three .ocio config files:
  • cg-config-v0.2.0_aces-v1.3_ocio-v2.1.2.ocio
  • reference-config-v0.2.0_aces-v1.3_ocio-v2.1.2.ocio
  • studio-config-v0.1.0_aces-v1.3_ocio-v2.1.2.ocio
  • Unzip and place the config in your user folder or on a server location.
  • On macOS I use Automator to create an App called “Blender_3.40_OCIOv2-beta”. In this app I use a shell script to set the OCIO environment variable and start Blender.
  • This time I want to use the studio config, because it provides some camera color spaces that are not provided (and not needed) in the CG-config. But be aware that at the moment there is no IDT for the ARRI Alexa available.

MAC “Automator” script

export OCIO=/Users/daniel/MEDIA/ACES/OpenColorIO-Config-ACES-0.3.0/studio-config-v0.1.0_aces-v1.3_ocio-v2.1.2.ocio

cd /Applications/Blender/blender.app/Contents/MacOS/

./blender

For now this did the trick and Blender starts with the new config and seems to run fine. I re-rendered the old scene I used for my Blender&ACES 1.2 setup guide and compared the two ocio-configs:

Blender 3.4 Alpha with OCIO v2 config – viewer set to Rec.709
Blender 3.40 Alpha with OCIO v2-ACES 0.2.0 config – viewer set to Rec709.

The render results are identical.

macOS 12.5 – 27″ iMac (Intel & AMD) bug

As I was setting up this test on my 2020 27″ iMac, I ran into display bug. By default the Device Display is set to “sRGB”. I rendered the first test images, and only the cyan sphere turned partly magenta somehow. I initially tested this is macOS 12.3, but the bug is sadly still persistent with macOS 12.5.

Blender 3.2 Alpha running a OCIO v2 pre-release config.
Blender 3.20 Alpha with OCIO v2-ACES 0.2.0 config – viewer set to sRGB.
Blender 3.20 Alpha with OCIO v1-ACES 1.2 config – viewer set to sRGB.

With the OCIO v1 config this never happened before. This only seems to happen when the Blender “Display Device” is set to sRGB! After I tested around a bit, I found out that changing the Display Device to Rec.1886 / Rec.709 Video does the trick. The image looks fine again.

Further testing and after posting a bug report for Blender, I realized that I cannot replicate the issue on a M1-Max MBP. So maybe it’s not even a Blender but a macOS issue.

https://developer.blender.org/T96590

I posted this “issue” also on ACESCentral in the following thread:

OpenColorIO 2 Configs for ACES


Furthermore I found out that the PNG writer in Blender from the Render View writes out a broken image. The JPG writer works fine.

I will continue testing and looking out for other problems and issues. For now I am happy to see a modern and small config running OCIO v2 that makes the life in Blender a bit easier when it comes to selecting the right colorspaces.

OpenColorIO-Config-ACES 0.2.0 config with a limited set of colorspaces.