2023 week 3: SL CCUG and TPV Developer meetings summary

Where Our Journey Begins, November 2022 – blog post

The following notes were taken from

  • My audio recording and chat log transcript of the Content Creation User Group (CCUG) meeting held on Thursday, January 19th 2023 at 13:00 SLT.
  • Pantera’s video of the Third Part Viewer Developer (TPVD) meeting held on Friday, January 20th, 2023 at 13:00 SLT, embedded at the end of this article.

These meetings are chaired by Vir Linden, and their dates and times can be obtained from the SL Public Calendar; also note that the following is a summary of the key topics discussed in the meetings and is not intended to be a full transcript of all points raised.

Note, The TPVD meeting was abbreviated to 20 mins.

Official Viewers Status – TPV Meeting

Available Viewers

  • On Thursday, January 19th, 2023, the Maintenance R RC viewer was updated to version – translation updates and the return of slam bits.
  • On Wednesday, January18th, 2023:
    • The Maintenance (Q)uality RC viewer was updated to version on – new Debug settings UI, quality of life improvements.
    • The PBR Materials project viewer updated to version, on January 19, 2023 – SSR support.
      • This viewer has been reported as “broken” when running on systems with AMD GPUs, a situation that was being investigation as these notes were being written.

This leaves the rest of the currently-available official viewer as:

  • Release viewer: Maintenance P (Preferences, Position and Paste) RC viewer version Monday, December 12, 2022.
  • Release Candidate viewers:
    • Performance Floater / Auto-FPS RC viewer, version, January 4, 2023.
  • Project viewers:
    • Puppetry project viewer, version, December 8, 2022.

General Viewer Notes

  • Vir pointed out that as Microsoft has ended support for Windows 8 on January 10th, 2023, it is no longer regarded as a supported operating system for running Second Life, and the viewer will not be tested against it (and the System Requirements page has been updated to reflect this, specifying Windows 10+ most recent service pack as the baseline supported Windows OS.
  • The second phase of the Github work in on-going, notably updating all the viewer build libraries.

Inventory Enhancement Project – Both Meetings

Linden Lab is looking to enhance the Inventory system.

  • The first element of this work is to be the addition of a fixed-resolution thumbnail preview capability, allowing users to see a small image of a given object (where this makes sense – so the likes of note cards and scripts would be excluded) within inventory, with these thumbnails either being of individual items or entire folders.
  • This work has now started, but it will be “some time” before there is anything user-facing to show.
  • A code contribution from Kitty Barnett (Catznip) for an inventory texture tool tip / preview may well be folded in to this work.
  • Once the thumbnail preview work has been completed, it is possible the Lab will look to further enhancements to inventory management. One future enhancement under consideration is support for folders to be included in the Contents inventory of individual objects.

glTF Materials and Reflection Probes – CCUG

Project Summary

  • To provide support for PBR materials using the core glTF 2.0 specification Section 3.9 and using mikkTSpace tangents, including the ability to have PBR Materials assets which can be applied to surfaces and also traded / sold.
  • To provide support for reflection probes and cubemap reflections.
  • The overall goal is to provide as much support for the glTF 2.0 specification as possible.
  • The project viewer is available via the Alternate Viewers page, but will only work on the following regions on Aditi (the Beta grid):  Materials1; Materials Adult and Rumpus Room 1 through 4.
  • Please also see previous CCUG meeting summaries for further background on this project.


  • Viewer:
    • Screen Space Reflections (SSR) has now been integrated into the Project Viewer, (January 19th onwards), although work around this is still being finalised, notably mixed Reflection Probes with SSR.
    • Some fixing is required to the default colour curves in the viewer.
    • Stability issues have been noted on Intel integrated graphics hardware, and these are being investigated / fixed.
    • There have now been a total of two further weeks focused on optimising the viewer’s performance, and the results of this work should be available in the next update to the Project Viewer.
    • UI updates: the viewer will likely see some UI updates as it progresses:
      • The next update will likely include a new dedicated icon for on the Build floater for creating Reflection Probes.
      • The drop-down in the Build floater Textures tab (Currently Materials and Media on the release viewer, may be re-labelled for PBR (where it is Materials, Media, PBR) to more clearly differentiate between the current materials maps system and “new”” PBR materials.
      • Similarly, the new Materials Inventory folder in the Project Viewer may also be renamed to avoid the potential for confusion between the use of PBR materials assets and the current materials maps system.
      • Further, the menu option Build → Upload → Materials (in the Project Viewer) may be reamed to more clearly reflect it is for PBR materials, not material maps.
      • Exactly was terms will be used is TBD, but the general push (from LL’s perspective is to use meaningful lbeels on options and menus which can be Googled with some relevance by those wanting to know more about the underpinning file formats / standards, etc.
  • Work is going into messaging between the back-end and the viewer to ensure it will scale once the viewer starts to see widespread use.

In Brief

  • As the PBR Materials project is approaching a possible RC release, the questions has been asked as to what is next on the graphics front. While no formal decision has been made, options include:
    • A return to looking at adding something like Vulkan / MoltenVK (for OS X) API support alongside of the OpenGL API (which has been slated for deprecation by Apple and is growing increasingly long in the tooth). This work is being looked at more as a performance optimisation rather than a visual boost to rendering (e.g. allowing SL to be less CPU-bound and make more use of the GPU, reducing the volume of draw calls, etc.).
    • Further expansion of the glTF work to include mesh (and moving away from Collada .DAE), animations, etc. But again, no definitive plans / direction has been agreed within the Lab.
      • While there is a appetite at the Lab to support as much as the glTF 2.0 specification, some aspects will be excluded from the list – mentioned at the meeting were Setting the filter mode and sampler state of textures, both of which were described as “problematic” for implementation within SL.
    • Overhauling / updating support / options for ground textures.
  • The CCUG meeting saw a general discussion on animations, the skeleton and all that it involves (bones, attachment points, collision volumes, rigging, etc., and the rules / policies surrounding them, couched initially in the potential for expanding the skeleton / avatar system – for which there are currently no plans to do so beyond what has already been done.
  • Pivot points: (related to the above) past CCUG meeting saw some extended discussion on implementing pivot points on the skeleton, and LL indicated they would investigate this. Since then, it has become increasingly apparent that a node hierarchy would be beneficial and potentially easier to implement; ergo pivot points have been pulled into the pot for a future hierarchy project.
  • There is a known bug where Premium Plus users  – who gain free texture uploads – are being charged for textures included in mesh uploads. An upcoming simulator-side maintenance update should correct this.
  • A request was made at the CCUG meeting to allow mesh uploads greater than the 64m single object size limit, to make it easier to import large structures  / scenes without having to curt them into sections (and thus avoid potential issues in fit, scale, update, etc, and can result in Interest List related rendering issues).
    • LL is unlikely to change the limit, but would prefer to provide improved tools that can help content creators / scene builders.
    • One should tool discussed – which is currently not in development – is that of a “scene view” tool which identifies every individual instance of an object in scene, and provides a mechanism to allow (subject to permissions, obviously) them to be swapped-out to fix things like “broken” items / those for which there is an update / replacement.


Next Meetings

  • CCUG: Thursday, February 2nd, 2023.
  • TPVD: Friday, February 17th, 2023.