Project Bento User Group update 11 with audio

Project Bento – extending the SL avatar skeleton
Project Bento – extending the SL avatar skeleton

The following notes and audio were taken from the weekly Bento User Group meeting, held on Thursday, April 14th at 13:00 SLT on Aditi. For details on each meeting and the location, please refer to the Bento User Group wiki page.

Note that this update is not intended to offer a full transcript of the meeting, nor does it present the discussion points in chronological order. Rather, it represents the core points of discussion to Project Bento, grouped together by subject matter were relevant / possible.

Viewer Status

A new version of the project viewer arrived on Thursday, April 14th. Version brings with it:

  • Addition of a mFaceChin bone to the face to support the use of appearance sliders
  • Addition of “Left Hind Foot” and “Right Hind Foot” attachment points
  • Added or improved support for a large number of sliders,  notably those for the avatar shape.

As previously noted, the slider support means that many of the Edit Appearance sliders will work with both the original avatar form (using morphs) and with mesh avatars utilising the Bento skeleton. This means that height can be adjusted via the sliders, the face can be adjusted (eye or mouth position, nose and chin shape, etc.). However, musculature changes are not supported as there are insufficient bones available to properly support this.  The update also includes a number of bug fixes, including one for some graphics glitches in the mesh upload preview.

Unless serious problems are encountered when using this version of the viewer, there are no plans to make further changes to either the skeleton or the sliders going forward, and the emphasis on viewer work will primarily be on bug fixing.

The humanoid avatar models on the Bento testing wiki page should also be updated to reflect these changes, and Avatar should have an update to match the skeleton shortly (if not already available).

Sliders and Animations

A point of note with linking the appearance sliders to the Bento bones is that they can change both the position and the scale of the linked bones. Any changes made using them may therefore clash with animations used within the avatar to also reposition the same bones, or may have an impact as a result of the scaling being changed via slider adjustments (Second Life currently doesn’t support the ability for animators to control bone scaling themselves). How to limit the impact of this when users are changing their avatar shapes may be an issue, although initial testing suggests that using bone rotations on those bones which are linked to the shape sliders can reduce the impact of conflicts.

The lack of bone scaling within the SL animation system is recognised by the Lab as a limitation, but is seen as being a separate project, were it to be addressed in the future, rather than something directly encompassed by Bento, due to the amount of work involved in defining the necessary tracks to manage scaling and extending the format for how scaling data is stored and represented.

Moving to Agni

The Lab is still looking to move Bento to the main grid (Agni) during the second quarter of 2016. The final time frame hasn’t been determined, but there may be more on this at the next meeting, however it is likely to be sooner rather than later. This means that the Lab will be focused on resolving the more major / obvious bugs people are currently experiencing and will be looking for feedback on experiences with the latest version of the project viewer ASAP.

Arrival on Agni won’t signify the end of the project, but it will mean that creators will be able to upload and test content on the main grid, and more users will obviously be able to see Bento content. The project will likely be promoted by the Lab through blog posts and videos, and they will be inviting people to submit their own Bento videos and content.  Details on how to get involved in this will likely be discussed at the next Bento project meeting.

It has been suggested that once Bento has been moved to Agni, the Mesh Dev in-world group becomes the medium for handling Bento related general discussions and information exchange for content creators, rather than establishing a dedicated in-world group.

Other Items

Partial Joint Offsets / Overrides

There has been some discussion on the forums concerning partial overrides and best practices with regards to the Bento skeleton, and Vir has offered some thoughts on the matter. Some problems have been encountered in using some of the bones within “worn” pets, with offsets with these bones appearing to affect others in the skeleton. However, further investigation is required to determine whether this is a potential issue, or possibly a problem within the models being used.


  • Odd deformations seen in the Bento viewer: Medhue's fly should be standing on all six legs, not standing upright
    Odd deformations seen in the Bento viewer: Medhue’s fly should be standing on all six legs, not standing upright

    Deformations: avatars are sometimes still being seen as deformed by some using the Bento viewer (prior to the latest release). The issue is still being looked into by the Lab as to potential cause or causes

  • Spine Joints: the added spine joints are proving difficult to use in some cases – snakes and similar are proving difficult to animate
  • “idle” animation state: when transitioning between animations, or when ending an animation, the default animation system uses an “idle” animation (e.g. if an animation generates a look of surprise on an avatar’s face, the “idle” animation will return the expression back to a neutral look when the animation stops running). However, because the default system is unaware of the Bento bones, then these “idle” animations get ignored (so that the avatar’s face remains stuck with the surprised look, for example, or a transition between animation states fails to ease-in / ease-out correctly). To avoid this, one suggestion has been to encourage animators to explicit set their own “idle” animation.

While not directly related to Bento, a long-standing issue was raised at the meeting: that of the default walk failing to play under a variety of circumstances (running an animation unrelated to walking / crossing from one region to another / wearing something / etc), with the result that the avatar appears to “slide” over the ground. While long-standing, it appears a JIRA has never been raised against it, so a request has been made for one to be raised so that the Lab can dig into things outside of Bento.

One thought on “Project Bento User Group update 11 with audio

  1. This is amazing progress. By the way, this means that mesh heads developed by third party developers could theoretically support complex facial expressions and even authomate mouth movements on voice speech?


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