Category: SL Tech

The following notes are taken from the Content Creation User Group meeting, held on  Thursday, July 20th, 2017 at 13:00 SLT at the the Hippotropolis Camp Fire Circle. The meeting is chaired by Vir Linden, and agenda notes, etc, are usually available on the Content Creation User Group wiki page.

Medhue Simoni live steamed the meeting to You Tube, and his video is embedded at the end of this article. These notes present the meeting in terms of topics discussed, rather than a chronological breakdown of the meeting, so the provided time stamps may appear to be out of sequence in places. All time stamps are provided as links which will open the video in a separate browser tab, allowing the discussion to be heard in full.

Animated Mesh

Project Summary

The goal of this project is to provide a means of animating rigged mesh objects using the avatar skeleton, in whole or in part, to provide things like independently moveable pets / creatures, and animated scenery features via scripted animation.

• At this point in time, this is not about adding fully functional, avatar-like non-player characters (NPCs) to Second Life
• Animated objects will not (initially):
  • Have an avatar shape associated with them
  • Make use of an avatar-like inventory (although individual parts can contain their own inventory such as animations and scripts)
  • Make use of the server-side locomotion graph for walking, etc., and so will not use an AO
  • Use the avatar baking service
• The project may be extended in the future.
• It will involve both back-end and viewer-side changes, likely to encompass new LSL commands to trigger and stop animations (held in the object’s contents)
• It will most likely include a new flag added to an existing rigged object type in order for the object to be given its own skeleton.

Current Status

[3:33- 4:29] Work is focused on getting right-click selections and wire frames to work correctly (e.g. when you right-click on a mesh, the object stops moving, the correct menu is displayed and the mesh is shown as a selected wire frame. All of this seems to be working well, and while Vir is still not in a position to give a time frame estimate of when a project viewer will appear, his feeling is that there are no major obstacles sitting in the way.

[13:24-16:54] Performance impact assessment: The work isn’t sufficiently advanced to carry out any kind of assessment on the impact multiple animated objects may have on simulator and viewer performance. Animated objects should not have as significant a cost as avatars tend to have, but it could get expensive with multiple rigged vertices being animated in a single location.

Vir’s view is that the relevant test will likely be how many joints are actively animated and rigged to, rather than just how many bones are in the scene, given that idle bones aren’t really going to impact anything. Until sress tests can be held and the figures refined, any cost / impact values assigned in a project viewer will be place holders, subject to change.

[43:50-58:00] Attaching animated objects to avatars / rigging prims or non-rigged mesh to skeleton bones:  A discussion encompassing BUG-134018 and attaching animated objects to avatars. Vir sees the problem with the latter as being primarily a performance question / costing issue (large numbers of objects with potentially no land impact be which influence performance).

Attaching avatars to animated objects (outside of sitting on them, as is done with vehicles, etc., currently) is seen as more complicated because the animated object is being controlled by a viewer-side skeleton about which the simulator has no notion, and so ideas of attachment points become vague, and questions open up on how things are tracked by the simulator, given there is no notion of agents associated with animated objects. This discussion also encompasses issues of attaching avatars to bones within animated objects, raising questions of parenting, animation synchronisation etc.

Bakes on Mesh

Project Summary

Extending the current avatar baking service to allow wearable textures (skins, tattoos, clothing) to be applied directly to mesh bodies as well as system avatars. This involves server-side changes, including updating the baking service to support 1024×1024 textures. This may lead to a reduction in the complexity of mesh avatar bodies and heads.

Current Status

[4:32-4:39] Anchor Linden has been working on other projects recently, but the hope is he’ll be back working on bakes on mesh soon.

[5:40-6:19] Bakes on mesh should allow alphas / transparent textures to be used as they are with the system avatar at present: if an alpha / transparent channel is in a bake, it will place “holes” in the mesh just as they can be used to blank parts of the system avatar. However, once the bakes on mesh project has progressed far enough, this will requiring testing to confirm.

[58:27-58:48] There is no estimate on when a project viewer, etc., for bakes on mesh might appear.

Other Items

Increasing the Build / Mesh Import Size

[6:24-12:18] It was asked if the current upper limit imported objects could be increased so that very large items such as region-sized landscape / terrain models could be imported with having to break them into smaller segments.

There are currently no plans to make any increase in the size of prims / single mesh imports. It’s also unclear how massive objects might be affected by land impact. The latter include things like the overall area of the object, the amount of screen space it might occupy based on its dimensions, etc; so having one large piece of terrain could have an exponentially larger land impact than  using a number of smaller sized pieces to achieve the same result. Additional concerns include the increased risk of encroachment issues, etc., for very large objects.

JIRA feature requests outlining why an increase might be useful and the kind of use cases it could meet are invited.

Maya .ANIM Exporter

[17:39-18:28] Aura Linden continues to work on the .ANIM exporter for Maya (which she has been developing in her own time), and which she plans to make available as a open-source offering. There are also the pre-Bento (translations on mPelvis only) and post-Bento (translations on all bones) .BVH exporters available on the Bento testing page of the wiki.

In Brief

• [18:59-19:42] Various requests were put forward to extend the mesh object physics types which can be specified at upload (e.g. cube, basic havok presets, etc.). Vir requested a JIRA be raised so it could be noted and as / if / when time allows, pain point could be looked at and perhaps improvements / changes to the uploader made.
  • [20:40-22:54] Discussion about a specific issue in uploading a model cat using the official viewer (which crashes) and Firestorm (which manages the upload).
• [25:13-29:26] Discussion (primarily text) on dynamic mirrors STORM-2055 and water as a reflective surface.
• [31:35-34:18] Discussion (primarily text) about BUG-134006 “Viewer code is not aligned to server code when calculating physics shape for thin objects”. This has been accepted by the Lab, but as it is seen as a conflict between the viewer and the server, no decision has been made on whether it should be a server-side or viewer fix. Firestorm have adopted a viewer-side fix, which will appear in the next release. The root of the problem appears to be changes made in the physics costings as a result of mesh being introduced. This is followed by a further conversation on the physics uploader, “custom pivot points, and issues through to 42:14.