2023 week 11: SL CCUG meeting summary

Gothbrooke Forest, January 2023 – 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, March 16th, 2023 at 13:00 SLT. 

These meetings are for discussion of work related to content creation in Second Life, including current work, upcoming work, and requests or comments from the community, together with viewer development work. They are chaired by Vir Linden, and dates and times can be obtained from the SL Public Calendar.


  • These meetings are conducted in mixed voice and text chat. Participants can use either to make comments / ask or respond to comments, but note that you will need Voice to be enabled to hear responses and comments from the Linden reps and other using it. If you have issues with hearing or following the voice discussions, please inform the Lindens at the meeting.
  • The following is a summary of the key topics discussed in the meeting, and is not intended to be a full transcript of all points raised.

glTF Materials and Reflection Probes

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.
  • In the near-term, glTF materials assets are materials scenes that don’t have any nodes / geometry, they only have the materials array, and there is only one material in that array.
    • It is currently to early to state how this might change when glTF support is expanded to include entire objects.
  • 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.


  • The PBR Materials project viewer updated to version, on March 15th 2023. Note that this viewer will only function on the following Aditi (beta grid) regions: Materials1; Materials Adult and Rumpus Room 1 through 4.
  • Texture handling / management:
    • As a result of data gathered by the Lab revealing a lot of users only have around 1 GB of texture memory, Dave P (Runitai Linden) has been making another pass through texture handling to making loading faster and memory use more efficient.
    • VRAM management has been improved to more selectively release texture memory on systems which might otherwise “run low” on available VRAM.
    • The hope is these will reduce texture trhashing issues (texture blurring, clearing, blurring, clearing) in the future for those so affected.
  • Geenz Linden continues to work on the Mac side of the PBR work; Comic Linden is finalising UV treatment  and Bed Linden is working on the one remaining server-side bug the team is aware of and  is working on atmospherics and issues with rendering them in linear space.
  • Brad Linden is working on a series of bugs in PBR materials handling where editing via LSL or manually sees the updates (changes) dropped rather than applied in various edge-cases and situations.
    • The simulator-side fixes for this issues are in place; fixes within the viewer are awaiting inclusion in a upcoming viewer update.

In Brief

  • glTF format for geometry (mesh), animations, etc., this is something the Lab does want to do, but will take the form of follow-on project(s) from the current glTF PBR materials work.
    • supporting glTF geometry imports is seen as a major project as it will likely require handling of arbitrary hierarchies, which is not something SL currently handles – although it is acknowledged that once done, will offer a lot of benefits.
  • There  was a general discussion on terrain improvements. This is something that LL had been considering, but content creators attending the CCUG meeting favoured the PBR work and graphics updates, so the terrtain updates have just to be put back onto the road map. Where it would slot, is not clear, as the desire from creators is to see the glTF work continue with geometry import support, etc., as noted above.
  • Another major graphic project waiting in the wings is the introduction of support for the Vulkan graphics API / MoltenVK (for Mac). This would likely take priority over any significant terrain work.

Next Meeting

  • Thursday, March 30th, 2023.


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