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ASWF TAC Meeting - July 14, 2021

Video Conference Link

Voting member attendance

  • Kimball Thurston - Chairperson, Weta Digital Limited
  • Bill Roberts, Adobe
  • Gordon Bradley, Autodesk
  • Tony Micilotta, DNEG
  • Bill Ballew, DreamWorks Animation
  • Christina Tempelaar-Lietz, Epic Games, Inc.
  • Brian Cipriano, Google & OpenCue Representative
  • Sean C McDuffee, Intel Corporation
  • Larry Gritz, Sony Pictures Imageworks
  • Jean-Francois Panisset, VES Technology Committee
  • Cory Omand, The Walt Disney Studios
  • Daniel Heckenberg - Animal Logic Pty Ltd / Industry Representative
  • Eric Enderton, NVIDIA
  • Sean Looper, Amazon Web Services
  • Michael Min, Netflix
  • Michael B. Johnson, Apple
  • Greg Denton, Microsoft
  • Sean O’Connell, Advanced Micro Devices
  • Mark Visser, Unity Technologies
  • Ken Museth, OpenVDB Representative
  • Michael Dolan, OpenColorIO Representative
  • Cary Phillips, OpenEXR Representative
  • Joshua Minor, OpenTimelineIO Representative
  • Chris Kulla, Open Shading Language Representative
  • Jonathan Stone, MaterialX Representative

Other Attendees

  • John Mertic, Linux Foundation
  • JT Nelson, Pasadena Open Source consortium / SoCal Blender group
  • Carol Payne, Netflix / D&I WG
  • Rachel Rose
  • Sergio Rojas, Arena World
  • Scott Wilson, Rust WG
  • Deke Kincaid, Digital Domain
  • Alex Meddick, Rising Sun Pictures
  • Jim Helman, MovieLabs



  • Open Source Days update?

    • John: most of you have been working with Rachel, we should be good there. Any questions? All seems good.
  • Project / WG updates

    • Assets WG (Wave): Animal Logic have a USD assets they want to contribute, but don’t currently have a direct project we can go to TSC to accept a production grade asset. So up to the TAC to decide whether an asset is acceptable. Went to USD working group last week, anyone want to volunteer to look at assets? Got a couple of volunteers, Mark Tucker at SideFX (Solaris architect), second person (?), would like to get more people to look at. Darin from AL has made asset available yesterday. Eric: we haven’t accepted anything yet, so don’t have a process yet. Intel and Amazon both offered assets, but didn’t have someone to review USD yet. Eric: an asset like that isn’t only used for USD, can have multiple uses for all sorts of developers both in studios, commercial vendors, researchers. What’s the process to add the ASWF “imprimatur” to determine that an asset is representative of a film grade asset in 2021. But also need to get the process going with some content. Question for John: can the TAC vote to accept an asset for this? Do we represent the ASWF in this way? Kimball: will we have an asset project that tracks all these assets? John: the Governing Board approval is more about using the license (which isn’t an OSI license per se). But to make the decision of “what is a film grade asset”, would see in the context of the project that governs / oversee the assets and should be responsible for this. So maybe time to transition from WG to project, and what the project would look like. Otherwise the TAC has to figure out the ownership structure of these assets. Eric: accepting an asset might not have to be a TAC vote, it could be at the project , just like accepting a PR. So can we put something in short order to approve the submission, since AL would like to have this up and running by SIGGRAPH. Jonathan: is there already a shading model associated to this asset? Wave: this is the chicken & egg with USD, they have a Hydra render delegate, but it’s been stripped off to provide a more generic USD asset. So it’s challenging to start with this. AL would like to get collaboration to develop other renderer bindings for the asset. Have been looking at it in different DCCs and USD View, there are lots of warnings. Hoping the SideFX volunteers will take a look at it. Eric: AL proposed there could be 2 versions, a vanilla version with standard USD Preview shaders, and a AL-specific version that would include future proposals. Jonathan: there are straightforward techniques to translate the shading model from proprietary to open source (presenting on that topic at SIGGRAPH). Can make a Material X binding. Eric: AL would have to be the ones doing this baking / flattening, doesn’t have to be perfect on day one. Kimball: this is where it fits the “project” model, different versions of an asset can be approved separately, with a TSC that can approve the versions. John: the project can make a determination of the qualifications on assets, and adopt the way the TAC can decide what is a good project. For turnover, if there’s a project proposal by the next TAC meeting, it could be accepted then. Eric: if the TAC wants to tell the current Asset WG, approvals can be done within the current WG membership. Vendors show up to a WG since they need the data to test the software, but studios may not. But looking to studio representatives to determine whether an asset is “film level”. Hoping for good representation from vendors and studios. Wave: so far we have 3 people who are from studios but at vendors now. Kimball: if the WG can write a project proposal, we can get this through at the next meeting before SIGGRAPH.

    • Material X / Jonathan. Main focus is prep for Open Source Days. 2 major contributions recently, a new set of BSD Graphs that were designed for RenderMan, means you can render the (LOMA?) nodes and preview, once committed and makes its way to USD repository, will be viewable in USD View (new version allows arbitrary Material X nodes).

    • OpenEXR / Cary: working on 3.1 release, mostly documentation at this point. Should be in good shape for next week, well in advance of Open Source Days. 3.1 is mostly Kimball’s work: new C language API for OpenEXR which is fast, thread safe. Trying to figure out how to communicate about this, but 100% backwards compatible with existing 3.0 release, purely an addition to the API. Missed the previous discussion with Francois/Nick about VFX Platform, but trying to get it in time to be adopted for next year. SO versioning is a pain, not easy to figure out, it’s more difficult than it should be.

    • OpenVDB / Ken: starting to review NanoVDB, still aiming for version 9, but not sure when it will drop, hoping to get into VFX Platform even if don’t make SIGGRAPH deadline. Gave a 2hr presentation, there’s an interactive viewer developed at NVIDIA which is useful but pulls in dependencies, so the viewer will go into a future release. 8.1 is wrapped up 2 weeks ago. SIGGRAPH long course, talk on NanoVDB, and prepping for Open Source Days.

    • OSL / Chris: discussed interactions between OCIO and OSL. Patrick Hodoul looking into this from number of angles, trying to figure out how the projects can play well together. Larry: this also implicates MaterialX. Jonathan: also have been having this conversation with Doug Walker. 2 paths: OCIO can start adding support for each shading language that MaterialX supports, but downside is already more than GLSL and OSL, and adding ESSL and SpirV. Or could emit MaterialX graphs directly. Haven’t come to a conclusion one way or another, but worth discussing. Michael: there’s an open OCIO GitHub issue about emitting OSL graphs. Jonathan: don’t want color transform support for just a subset of shading languages. It would be better if can decouple code generation from color transforms. Larry: that’s a MaterialX centric approach. But if you look at it from point of view of OSL inside renderer, MaterialX is on the outside, could require lots of steps involved. Don’t have a simple solution, but each solution imposes constraints on the other projects. Jonathan: would be nice if all ASWF projects one platform for color transforms, OCIO, and one platform for shader generation, MaterialX. But would make MaterialX a dependency of OCIO. Michael: GLSL support is optional dependency, can optionally build support module. Jonathan: right now MaterialX has to maintain every shading language it supports, so sticking to documented / open source shading languages. Shouldn’t be necessary for anything depending on MaterialX to know which shading languages it supports. Would have to be able to generate shading code from OCIO 2.0 configs for each supported shading language.

    • OCIO / Michael: also preparing for Open Source Days, and SIGGRAPH Long Course (that work is done and ready to go). Finalising 2.1 release, as well as 2.0.2 release around same timeframe. 2.1 has PR for support for imath 3 for half float support, recently merged support for ACES 1.3 gamut compression, starting discussion around OSL / MaterialX. Top of OCIO issues, looking for any thoughts on the topic.

    • D&I / Carol: just had monthly meeting. Preparing for Open Source Days talk, somewhat different format, fewer slides, more people stories. Summer program going great. All “mentees” got tickets to Digipro and Pipeline Conference. Rachel: 20 great students, thank you everyone who helped with reviews and mentors. Students keen to learn about our industry and careers, got a lot of support. Gnomon has been fantastic, gave great discounts and free licenses.

    • OTIO / Josh: have been working with Autodesk to help move forward proposal to bring spatial coordinate systems into OTIO: aspect ratios, positioning of clips in 2D plane, maybe moving slower than they would like, but looks like good direction for OTIO to move in. Having code review / design meetings with Autodesk, who is being fantastic. Getting ready for Open Source Days, a bit behind on getting presentation ready, but have great contributors. A bit stuck with Linux Foundation and Pixar with wording of one of the TSC agreements, not sure how to get that unblocked.

    • Rust / Scott: sent proposal to OpenEXR Slack channel to move ownership of OpenEXR Rust bindings to OpenEXR TSC, looking forward to discussion at next TSC meeting. Also LF has ownership of crates on, need to add someone else to the ownership to allow someone else to push work, right now blocked with LF RelEng team, need someone from TAC to bless that request. Kimball: we can figure it out at tomorrow’s TSC (13:30 PDT tomorrow).

    • OpenCue / Brian: preparing for Open Source days, on track, have a few different presenters. Early design discussions for redesign of scheduler. Also focussing on docs refresh, looking for a tech writer to help with that. TSC members helping with that.

    • USD WG / Cory: working on OS Days presentation, will meet next week so may have more to update after that.

  • Lifecycle resumption

    • Maybe have to wait after SIGGRAPH. John has updated the lifecycle document, idea that we review WGs and projects on a regular process, wrap up a WG, convert a WG to a project… We need to start doing this, good example will be proposal to convert asset WG to a project (adding to agenda for next meeting).
  • Talking through a WG proposal for real time “standards”, is it a good idea for this group or not

    • Some people at WETA interested in talking about interchange “standards” for real-time applications like Unreal, Unity, how do we mix data that has different structure than what we are used to dealing with. But don’t know if this is a good / appropriate forum for this, or should it be handled outside of ASWF. But we are a collection of people who have a shared interest.

    • Jonathan: could be interesting to review which projects apply and don’t apply to RT projects. OCIO, USD have a level of acceptance in Unreal/Unity, could be another lens to view the projects represented here. Larry: these tools are becoming important in most studios, looking for interoperability, potentially very relevant. Michael: what do you want to get out of this discussion? There’s now a new LF Open 3D engine foundation starting up? What do we want to get out of this? Kimball: fundamental goal would be to determine if there are tools that need to be built, and how do we share data consistently. There’s a lot of overlap, and it’s unclear if we’re confusing our scope by trying to talk about an “interchange agreement” if there’s no code involved. But maybe there is code. Wave: this is now part about film and TV workflow, so it is a legitimate part of it. Michael Min: seems like a good idea, there is a convergence happening, could be a good discussion. Also help organize the conversation from our perspective so we can help groups that are setting standards. For instance camera manufacturers want to be the “master clock” on location, but they need to know what they are interfacing to.

    • JT : intersection of Open Standards and Open Source, discussion on #random channel in Slack. Author Guy Martin is in ASWF Slack, may want to invite him.

  • Jonathan: some developers at ILM have been asking about open sourcing a Maxwell shader ball, could be a good contribution to the asset repo, could potentially be all in USD.

  • Eric: will try to look at Project application form, and try to see how it can map to what the Asset WG is doing. Kimball: getting the TSC structure right will be the important thing. Also structure around setting up web / wiki pages to describe the use of the content. Michael: anyone interested can reach out to Eric / Wave to help.