Project Bento User Group update 13 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 28th 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.

Issue Fixes

Partial Joint Offsets

As noted in my last update, one issue facing Bento is in how best to handle defining partial joint offsets – a mesh that specifies the override positions for some of the joints but leaves  other joints alone, which would allow different meshes to be mixed and matched to create an avatar look. Currently, the viewer doesn’t handle  multiple root bones in a mesh with partial rigging correctly, and to help correct this, Vir Linden has published a proposal for moving forward. Essentially, this would filter out any joints which have a position unchanged from their expected default, even if the mesh claims to use an offset, with only a very small adjustment (0.1mm or greater) is required to have a joint treated as having its own offset.

Offset and Slider Conflicts

Another issue which has been discussed recently is that joints offsets (notably translation offsets) can conflict with adjustments made using the appearance sliders, resulting in adjustments made using the sliders “snapping back” to their original location on leaving edit shape or following a relog or after removing / rewearing the avatar mesh.

An adjustment has now been made so that where an offset has been set for a joint, adjustments made using the sliders which only affect the offset will be ignored, only changes to the scale of a joint (length, height) made using the sliders will work. It is thought that this fix will also address the likes of BUG-11854.

Work in progress: Aki Shichiroji demonstrates a wearable wyvern utilising Bento bones for animation.

Work in progress: Aki Shichiroji demonstrates a wearable wyvern utilising Bento bones for animation.

It has also been noted that BUG-10991, “[Bento] Mesh rigged to the new joints either partly disappears, collapses or melts when viewing that avatar as an imposter” has not been fixed with the latest version of the project viewer. It will hopefully be one of the issues addressed with the next update.

Next Viewer Update

The above fixes, coupled with other work which has been carried out are regarded as being sufficient to kick-off another update to the project viewer, although there is a further piece of work Vir hopes to include. If all goes according to plan, this should see a new version of the Bento project viewer appearing in week #18 (week commencing Monday, May 2nd).

Animation File Size Limit

Currently, there is a file size limit of 120 Kb on animation files enforced by the back-end servers. With the increased number of bone available for animation. As it is now possible to animate a far large number of joints, some creators have started to find this limit a problem, and a request has been put in for it to be increased (see BUG-11836).

While there is potential for this to be done, it is currently unclear how much the file size limit should be increased. There are also other considerations to take into account, such as the intention for animation assets to be moved to the CDN for better delivery.

If there are specific examples of animation with large file sizes which could be attached to the JIRA as examples, they would be welcomed by the Lab. It has also been suggested that the Lab establish a best practices guide for animations files on the wiki.

This lead to a brief discussion on interpolation and the differences between .BVH and .ANIM animations, with Vir providing background information on how each are respectively handled.

Sliders for Remaining Bento Bones

While many Bento bones  – notably those of the face / head – have been tied-into the existing appearance sliders, there are still those which do not have slider support because they would require the development of dedicated sliders. this has been considered outside the scope of the initial Bento work, and it is far from certain it will be taken up in the near-term future, if at all.

Part of this comes down to the added complexity further sliders would thrust into the viewer UI, and also – as Vir explains – because the use of many of the Bento bones is intended to be arbitrary, therefore providing sliders to adjust them may not suit all of the uses to which they might be put, and cause further confusion / unpredictable results when used.

BentoRoll-out to  Agni and Lab Chat

An upright coyote Medhue Simoni is developing for Coyot Linden

An upright coyote Medhue Simoni is developing for Coyot Linden using Bento capabilities

Torley Linden is now working on the Agni roll-out videos for Bento. content creators who have models (complete or otherwise) using the Bento skeleton who would like to be considered for inclusion in the videos should contact Torley ( or Tory ( as soon as possible. In particular, Torley would like to hear from anyone who has perhaps been experimenting with using the bones to animation fashion and appearance accessories (e.g. hair, gowns, etc.), or who have demonstrations of animation previously impossible in SL, such as finger movements, facial movements etc.

The target for deploying Bento to Agni remains Q2, possibly late May, but certainly by the end of June unless something major occurs.

Again, as previously noted in this updates, this doesn’t mean the project will be “complete”. The viewer will still be iterating through project and release candidate cohorts as bug are found or necessary improvements are noted (although these are unlikely to include any changes to the skeleton). However, it does mean that Bento content can be uploaded to the main grid and viewed through any video incorporating the Bento updates, as these reach RC status and are adopted by TPVs.

As I’ve reported elsewhere, the next Lab Chat session, scheduled for Friday, May 6th, will include Project Bento, with both Oz and Troy Linden answering question on the project (see the forum thread to place questions). There may be an opportunity to screen Bento related videos for the audience attending the event.

Other Items

“Bone Standardisation”

A point of discussion through Bento has been on the subject of “bone standardisation” – providing some guidelines of which bones should preferably be used to achieve certain results in order to avoid potential conflicts for users when wearing multiple Bento items (e.g. if modelling hair, than “group x” of bones should preferably be used; if modelling wings, then “group y” should preferably be used; if animating a gown or dress, then “group z” should preferably be used, and so on).

There are apparently no plans on the Lab’s part to make such recommendations, although it is recognised content creators may wish to do so. See also an initial discussion here.

Medhue Simoni Videos

Medue Simoni has been producing both demonstration and tutorial videos to help content creators get more familiar with Bento, and I’m embedding his latest below as a further example of what Bento. can achieve.

Next Meeting

There will not be a Project Bento User Group meeting on May 5th due to a conflict with an internal meeting at the Lab. The next user group meeting will therefore be on Thursday, May 12th at the usual time of 13:00 SLT on Aditi.

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