Category: SL Tech

The following notes were taken from my audio recording and chat log of the Content Creation User Group (CCUG) meeting held on Thursday, July 7th 2022 at 13:00 SLT. These meetings are chaired by Vir Linden, and their dates and times can be obtained from the SL Public Calendar.

This is a summary of the key topics discussed in the meeting and is not intended to be a full transcript.

Materials and PBR Work

Please also see previous CCUG meeting summaries for further background on this project.

Outline of Work

• Work on an implementation of reflection probes which can be used both with PDR shading and with legacy content.
  • The overall aim of this work is to provide a means to support more physically accurate reflections in SL than can be currently generated (seen as a requirement for PBR support).
  • It applies to both PBR generated content, once available, and to legacy content.
• Creating a materials type with an associated inventory asset. This will initially comprise the ability to copy a texture entry (with its specific parameters) to inventory, to be followed by initial work to work implement a PBR graphics pipe in the viewer.
• Normals will likely be MikkTSpace, as per the glTF specification, but work needs to be done to see if supporting this could lead to clashes with the current normal maps rendering. This does mean that current Normal maps will not work on PBR materials.
• The initially supported capabilities are:
  • RGB albedo + transparency.
  • RGB Occlusion/Roughness/Metalness: R = occlusion, G = roughness; Blue = metalness.
  • RGB emissive.
  • RGB normal (- alpha).
  • Double-sized supported (disables backface calling before issuing the draw call).
  • Two-sided lighting (so if the back of a triangle is visible, it flips the normal around).
• In addition:
  • There will be an ability to “preview” materials on an item within your own viewer (similar in nature to Local Textures) before actually uploading them.
  • LSL support is still being defined, but should at least allow individual texture UUIDs to be replaced under script control.
  • The approach being taken is to may the system extensible so that further capabilities / plug-ins / options can be added with relative ease in the future.
  • However, Displacement maps will not initially be supported due to not being defined in the core of glTF 2.0; nor will any extensions that are not adopted into the core glTF standard (either glTF 2.0 or 3.0).

Current Progress – PBR Rendering

• Progress has been made on both the back-end and within the viewer, the latter elements being focused on hooking up EEP to work with PBR.
• There is currently an issue with Mac OSX due to the cube map being used at present, but this will be addressed.
• Given the work is still on-going, there is nothing as yet directly visible viewer-wise for users to test (on Aditi).

New Starter Avatars

There was some discussion of the new all-mesh starter avatars (see: SL19B MTL – the Moles (new starter avatars + Linden Homes)), reiterating / stating:

• This is not a re-working of the avatar system; it is aimed towards providing incoming new users with:
  • A selection of mesh avatars with which they can gain familiarity in terms of using / customising.
  • A supporting ecosystem of clothing / accessories rigged to work with the avatars / existing slider system.
  • A “stepping stone to allow them to more readily move towards more complex mesh avatar bodies / heads.
• It is hoped that as the system starts to mature, avatar clothing / accessory makers can be encouraged to support these new avatars by providing clothing / accessories of their own (and also adding to their income stream by doing so).
• There is a concern that the new avatars will be rejected by the existing community, so information will be made available to creators, etc., as the system reaches a point where reliable information can be shared.

In Brief

• llSetEnvironment (for scripted EEP changes) should start being deployed in an upcoming simulator maintenance updates.
• Currently, there are no plans to extend materials support to Bakes on Mesh; current materials or PBR.
• Additional avatar slider discussion:
  • A further request was made for a global scaling slider for the avatar. This was described as being harder to implement that might appear – although not impossible.
    • Part of the problem is the complexity involved in adding a new slider to work within the existing system, and the impact it has on other back-end systems (such as the Bake Service) which then also need to be tested / updated.
    • It is also unclear how the animation graph could be impacted / adjusted to allow for realistic, size-based strides with walking (e.g. so very large avatars don’t appear to be taking disproportionately small steps or tiny avatars are zipping along like they are jet-propelled -although given what is currently possible, it’s not clear if trying to address issues like these would be seen as a requirement by users.
    • As such, while the request has been noted (and has been subject to feature request Jira, it is described as being on the “back burner” of work LL would like to get to at some point.
  • Gender: a request was made to make the Gender slider less of a binary male / female choice. A modification to TPVs helps to provide this – for which LL now has the details – but it would be better to have official support.
• The inverse kinematics system as a whole is being looked at as a part of the avatar puppeteering (formerly avatar expressiveness) project.
• Larger prim sizes than 64m: currently not under consideration; however, LL interested in learning more about how-where they would be used, so they might better determine size ranges, etc., and in preventing Land Impact making structures created by large-scale prims becoming unaffordable.
• Non-physical region surrounds (e.g. by using environment settings to create a 360-degree panorama): still more in the discussion stage internally at the Lab rather than anything likely to be implemented in the foreseeable future.
• Mojo Linden indicated he would like to be able to give some kind of a representative low-poly bakes that would be vertex-shaded, the idea being to give a greater sense of the “vastness” of Mainland than can be gained from extending Draw Distance (which would also have a viewer performance hit in trying to render everything within DD range). These would then someone “fade away” and be replaced by the “real thing” as an avatar moves towards them, with further low-poly bakes appearing in the distance.
  • This is not an immediate project, but something Mojo would like feedback on, in terms of being something worth time in the LL considering.
  • If this were to become a project, the emphasis would be on the bakes being very low-poly, and the progress from a bake to actual objects would not be seamless.
• Terrain texture update: this has been previously discussed, but was put on hold as creators favoured PBR support. However, it is something the Lab will be getting back to in the future – with the potential for PBR support to potentially be extended to the terrain as a future PBR project, with possible PBR texture painting (grass, plants, dirt, etc.).
• There was a general discussion on land: pricing, products, instancing regions (e.g. event / experience regions) being able to spin-up / down regions when in use / not in use.
  • All of these ideas are subject to internal LL discussions, and some have their own inherent challenges (e.g. how do you account for spinning-down regions in which there are scripts running that have an expectation the region will be available 24/7, such as breedables?; how do you offer variable sized regions (e.g. 128mx128m or 1024x1024m) when the system is built around the expectation of a uniform region size (256x256m)?).
  • Beyond ideas being discussed internally and seeking feedback from users, nothing is on the current roadmap in terms of new land products.

Next Meeting

• Thursday August 4th, 2022.