OCIO Aliases Feature Not Fully Working #96049

New Issue

Zijun Zhou · 2022-02-26T22:07:51+01:00

Zijun Zhou commented

2022-02-26 22:07:51 +01:00

System Information
Operating system: Windows-10-10.0.19043-SP0 64 Bits
Graphics card: NVIDIA GeForce MX130/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 511.79

Blender Version
Broken: version: 3.2.0 Alpha, branch: master, commit date: 2022-02-25 22:47, hash: ac3f4db719
Worked: none

Short description of error
OCIO has an Aliases feature, here is the description from official OCIO doc:

The aliases key is used to define alternate names for the colorspace. For example, it may be useful to define a shorter version of the name that is easier to include in texture path >names. Or it may be necessary to define an older version of the name for the color space for backwards compatibility.

aliases: [shortName, obsoleteName]

This is an important feature to keep the "Filmic upgrade to OCIOv2" new config to be backward compatible with older *.blend files.
However it does not seem to work in Blender, I suspect it to be a bug.

Exact steps for others to reproduce the error
For simplicity of the bug report, I will not use the AgX (Filmic upgrade) config here.
Based on default Blender

Open the config.ocio file with any text editor, find the stanza for the color space "Linear"
Change the name to whatever, I am changing it to Linear BT.709 [D65](https://archive.blender.org/developer/D65)
add a line under it and type aliases: [Linear]
Now it looks like this:

I will leave the roles untouched, leave the scene linear and default float roles etc. to be Linear for testing purpose.

Save the file and open Blender, open compositor, check use nodes, and drag & drop an open domain/scene referred EXR, see the default float role still works, and scene linear space is also the Linear BT.709 [D65](https://archive.blender.org/developer/D65) space. Check system console, no related error message. This means the aliases work within the config itself.
Now open an older *.blend file saved with the previous config that has open domain EXRs, like this one:
Test Aliases.blend

See the input colorspace setting on the node is empty, and open system console, you see error message:
Color management: image colorspace "Linear" not found, will use default instead.

This means Blender is having a bug with aliases, since aliases works perfectly within the config itself. After you do some operation, Blender will select the colorspace based on the roles, but this would not work for "Non-Color" for example. This is an important feature for AgX (Filmic's upgrade to OCIOv2) to be backward compatible, hope the bug can be fixed soon.

**System Information** Operating system: Windows-10-10.0.19043-SP0 64 Bits Graphics card: NVIDIA GeForce MX130/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 511.79 **Blender Version** Broken: version: 3.2.0 Alpha, branch: master, commit date: 2022-02-25 22:47, hash: `ac3f4db719` Worked: none **Short description of error** OCIO has an Aliases feature, here is the description from official OCIO doc: >The aliases key is used to define alternate names for the colorspace. For example, it may be useful to define a shorter version of the name that is easier to include in texture path >names. Or it may be necessary to define an older version of the name for the color space for backwards compatibility. > >aliases: [shortName, obsoleteName] This is an important feature to keep the "Filmic upgrade to OCIOv2" new config to be backward compatible with older *.blend files. However it does not seem to work in Blender, I suspect it to be a bug. **Exact steps for others to reproduce the error** For simplicity of the bug report, I will not use the AgX (Filmic upgrade) config here. Based on default Blender 1. Open the config.ocio file with any text editor, find the stanza for the color space "Linear" 2. Change the name to whatever, I am changing it to `Linear BT.709 [D65](https://archive.blender.org/developer/D65)` 3. add a line under it and type `aliases: [Linear]` Now it looks like this: ![image.png](https://archive.blender.org/developer/F12888212/image.png) I will leave the roles untouched, leave the scene linear and default float roles etc. to be `Linear` for testing purpose. 4. Save the file and open Blender, open compositor, check use nodes, and drag & drop an open domain/scene referred EXR, see the default float role still works, and scene linear space is also the `Linear BT.709 [D65](https://archive.blender.org/developer/D65)` space. Check system console, no related error message. This means the aliases work within the config itself. 5. Now open an older *.blend file saved with the previous config that has open domain EXRs, like this one: [Test Aliases.blend](https://archive.blender.org/developer/F12888228/Test_Aliases.blend) See the input colorspace setting on the node is empty, and open system console, you see error message: `Color management: image colorspace "Linear" not found, will use default instead.` This means Blender is having a bug with aliases, since aliases works perfectly within the config itself. After you do some operation, Blender will select the colorspace based on the roles, but this would not work for "Non-Color" for example. This is an important feature for AgX (Filmic's upgrade to OCIOv2) to be backward compatible, hope the bug can be fixed soon.

Zijun Zhou commented

2022-02-26 22:07:51 +01:00

Added subscriber: @Eary

Evan Wilson commented

2022-02-26 22:37:47 +01:00

Added subscriber: @EAW

Jesse Yurkovich commented

2022-02-26 23:44:38 +01:00

Added subscriber: @deadpin

Jesse Yurkovich commented

2022-02-26 23:44:38 +01:00

Changed status from 'Needs Triage' to: 'Confirmed'

Jesse Yurkovich commented

2022-02-26 23:44:38 +01:00

Confirmed. Blender will load all the colorspaces at startup into its own list and only uses the name when referencing them from this list later on. As such, only Linear BT.709 [D65](https://archive.blender.org/developer/D65) is known and not any of the aliases.

Confirmed. Blender will load all the colorspaces at startup into its own list and only uses the `name` when referencing them from this list later on. As such, only `Linear BT.709 [D65](https://archive.blender.org/developer/D65)` is known and not any of the aliases.

Steffen Dünner commented

2022-02-27 16:01:12 +01:00

Added subscriber: @SteffenD