November 30, 2020

Host: Michael Dolan

Attendees:

  • [X] Mark Boorer (TSC) - Industrial Light & Magic
  • [X] Mei Chu (TSC) - Sony Pictures Imageworks
  • [ ] Sean Cooper (TSC ACES TAC Rep) - DNEG
  • [X] Michael Dolan (TSC Chair) - Epic Games
  • [X] Patrick Hodoul (TSC) - Autodesk
  • [ ] John Mertic - Academy Software Foundation / Linux Foundation
  • [X] Carol Payne (TSC) - Netflix
  • [X] Mark Titchener (TSC) - Foundry
  • [X] Carl Rand (TSC) - Weta Digital
  • [X] Doug Walker (TSC Chief Architect) - Autodesk
  • [X] Kevin Wheatley (TSC) - Framestore
  • [x] Bernard Lefebvre - Autodesk
  • [x] Deke Kincaid - Digital Domain
  • [x] Joseph Goldstone - ARRI
  • [x] Matthias Scharfenberg - Industrial Light & Magic
  • [x] Nick Shaw - Antler Post
  • [x] J Schulte - Industrial Light & Magic
  • [x] Alessandra Tomassi - Industrial Light & Magic

OCIO TSC Meeting Notes

  • Doug to recap goals of OCIO v2 and relation to OCIO mission:

    • Some recent discussions about controversial topics. Thought it would be useful to recap what we're doing with v2 from AD point of view - clarify motivation for some of these new features. As written in origin proposal, goal is to be able to use OCIO across apps more broadly, and to rely on it entirely as our color management system (CMS). We would like to standardize on OCIO across apps. Need OCIO to do a variety of color management tasks. When thinking about how OCIO is used, there's color space based transformations (OCIOColorSpaceNode, etc.) and other operations which are more ignorant of color spaces (OCIOFileTransform, etc.). In ideal world, only the former would exist, since it requires the least knowledge from user. Reality is though there is need for people to apply independent transforms, in apps where it's expected the user knows a reasonable amount about color management (e.g. Flame - users know how to load a LUT and apply it). Don't want two separate libs for applying LUTs. For things like dynamic properties and NamedTransform, it's more the latter case, using the same CMS to apply the independent transforms. We aren't trying to change the existing config way of working - very supportive of that workflow. Don't want to enable people with ability to edit individual transforms in a config to edit look of a config.
    • Mark B: Caught up with Doug offline to discuss. The way Doug describes it now, it makes sense. Objections were based more around how these features would map to configs. Some of the objectional features don't map to configs, so we're ok with that.
    • Deke: Really useful for tools like Nuke, where you have to jump over a wall to implement things differently based on what workflow you are doing. Would be nice if Foundry could have one code path instead of two separate ways.
    • Mark T: Agree. We would like that too and hope to standardize on OCIO in Nuke and across products.
    • Doug: Would be helpful to write whitepaper to try to establish best practices. Sometimes we have people who are asked to implement color management but are not color management experts, and implement without being aware of best practices. Think having something that documents this more extensively than current docs would be helpful. Hope TSC can focus on this once v2 is out. Help people understand color management and implement it correctly.
    • Deke: Any support for deep merging of multiple configs?
    • Doug: There is a way to convert between multiple configs in OCIO v2. USD for example could reference one scene config, and import an asset using another config. We added a processor command which can convert between a known color space present in both configs. Looks for these two roles that have been added which act as an interchange. Also added a version where you can provide your own interchange (common color space used across studio).
    • Deke: No way to merge two configs though? To support vendors having configs which inherit from each other.
    • Doug: No.
    • Mark B: Any use case where you're trying todo that?
    • Deke: If vendors could have their own internal config and add it on top of yours. You could add it above or below and merge them together and have access to those transforms. Also for MaterialX, USD, etc. Point to someone else's config to get transforms without cleaning up and ingesting.
    • Mark B: Need to use the solution Doug describes since you don't know if the two config are compatible.
    • Deke: Could also be a studio vs show level config.
    • Mark B: We have same thing, facility, show, shot. We merge them through custom sanitizing tools.
    • Deke: Same. Inherit from ACES config and build on it.
    • Mark B: Might put out another doc to clarify what was discussed with Doug offline. Might be more to discuss but inconsequential compared to other stuff.

  • Named Color Transforms - Continued discussion:

    • Michael: Is this topic still up for debate? Or was it resolved through offline discussion?
    • Mark B: Didn't cover this topic. Still up for discussion.
    • Doug: We implemented ability to make NamedTransforms inactive. Commit pushed to existing PR that does this. Zach proposed alternative way to make them inactive. I replied that we are open to implementing that instead of or along with what was done. His idea was to use env var to disable named transforms all together, instead of treating them as inactive color spaces where they are disabled one at a time.
    • Michael: Could be good to have a config attribute in that case too since the env could be cleared accidentally when shelling out to a process. That would prevent it in a persistent way. Like how active displays and views are handled currently, with env var or config property.
    • Doug: The individual inactive flags are persistent, so can be used in that way.
    • Michael: Does that answer ILM concerns?
    • Mark B: Our concern is feature itself, not the implementation. And how it's exposed inside of tools. Does processor take NamedTransform constructor?
    • Doug: Would call getProcessor which takes generic transform, and pass in NamedTransform. Same approach as using FileTransform.
    • Mark B: Based on conversation earlier, don't have strong objection. If intent to enable DCC to expose individual transforms where they won't get confused with other transforms.
    • J: Yes, and this is progress on previous discussion. With beta going out and implementation being considered, need to get standardized view on implementation.
    • Mark B: In terms of enabling/disabling, like active displays/active users, sounds reasonable.
    • Carol: As aside, another useful case Matthias and I were discussing. This would be the perfect vehicle for the ACES gamut compression transform. Would be nice to be able to do that separately, in ACES config. Fits nicely.
    • Mark B: One point we discussed. Two very separate use cases for OCIO. One we're trying to defend is config author creating black box, being represented properly. Second use case with graph and a skilled artists making decisions with toolbox of consistent math. In terms of first users, don't see much use for NamedTransforms. Can see benefit for second group of people though.
    • Michael: Use of NamedTransforms could be covered in Doug's proposed whitepaper too.
    • Nick: Would that be a separate node in Nuke?
    • Mark B: Think so
    • Mark T: Yes, think that would be the case.
    • Michael: Wanted to propose we form a UX working group to discuss these topics and forming standards for OCIO v2 implementation in DCCs. We could transition from the doc working group to that. If anyone is interested in helping lead that, please reach out.
    • Others: Agree.
    • Deke: ACES has own UI rules, could collaborate between projects.
    • J: Don't think OCIO UX being involved with ACES is good fit, since there are workflows that don't involve ACES.
    • Doug: As config working group moves forward a lot of the same questions are going to come up. A lot of questions from initial config discussion was on things like naming and interface.
    • TODO: Michael will help organize a UX working group.

  • Categories discussion (Issue #1222):

    • Doug: At last TSC meeting talked about this. Created issue #1222. Trying to collect a number of new features and discussions on how color spaces appear in application menus. Motivation is the new categories attribute. Hadn't gotten to the list of proposed categories, or sorted out how we expect applications to use this. Want to make sure we're all on the same page in case tweaks are needed to get this working as expected. Proposed some tweaks in the issue. One of the things that came up in v2 working group meetings was request from people that they want to specify, from studio perspective, env vars to filter color spaces for artist groups, like compositors, lighting artists, modelers, etc. Different from app developer point of view with different menus for tasks. Proposed both use cases and something which could work on both ends. Want feedback on whether I've captured this correctly. See issue content: https://github.com/AcademySoftwareFoundation/OpenColorIO/issues/1222
    • Kevin: Have existing concept of roles. Fixed set of assumed roles plus extended set. How would we choose to filter those with this. Nuke now shows roles in menus, and would be good to filter those as well.
    • Doug: App helpers code has setting to show roles or not.
    • Kevin: Want users to find the roles they want to find. Artists trained to use particular roles for certain tasks.
    • Deke: Mari has roles listed too, and has its own roles.
    • Mark B: Intention for roles was just to make sure basic color spaces were there. Roles have been misused since then. Don't think roles should appear at all in menus.
    • Deke: Like roles there, but need to filter them.
    • Mark B: Category system is powerful. If DCCs have prefs as to what category might be associated with a dropdown (i.e. texture in Maya). DCCs can assign categories to UI elements and only show those. Don't think this should be OCIO-wide env var. Should be per-DCC.
    • Doug: Yes, would be fixed for certain menu. Specific documented category so config authors know what an app uses.
    • Mark B: Could end up with overlapping categories. If up to user they could define that themselves.
    • Doug: Proposing standard categories to encourage consistency, but doesn't need to be limited to this. The key part is there is a set pre-defined to an application. So Maya would say what categories it's using for different menus. There is another set that is end-user defined and would expect to find those at runtime.
    • Mark B: What if you have both types of categories?
    • Doug: Then would use the intersection. So for texture, you could have file-io intersected with an end-user environment variable (basic-3d etc.)
    • Mark B: If either is empty, defaults to other?
    • Doug: Yes.
    • Mark B: Would make these categories configured by the config author. DCC authors would allow users to customize the category names, or fallback on the default list.
    • Carol: Something to fall back on is good. Most people just use defaults. Don't have a problem with proposed options.
    • Mark: Defaults from DCC (as documented) is fine. Want to avoid problem with roles where categories are inconsistent between apps. If all left to user can be very explicit.
    • Michael: More topics for discussion at UX group.
    • Mark T: Agree. Highlights importance of best practice to show how things are intended to be used. Developer may not find the right thing and use something outside standard use. UX stuff really important.
    • Mark B: App helpers has concrete implementation for reference.
    • TODO: All: Read through issue #1222 and provide feedback there or in next TSC meeting.

  • Items for next TSC meeting agenda:

    • Finish discussion on standard categories.
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