Project Bento User Group update 15 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, June 16th at 13:00 SLT at the the Hippotropolis Campfire Circle . For details on the meeting agenda, 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, grouped together by subject matter were relevant / possible, whilst maintaining the overall context of the meeting.

Simon Linden and Whirly Fizzle wear horse avatars by Teager. Whirly has clearly been Torleyfied!
Simon Linden and Whirly Fizzle wear horse avatars by Teager. Whirly has clearly been Torleyfied!

Viewer Status

As noted in my current viewer releases page and this week’s SL project update, the Bento project viewer updated to version on June 10th. This release primarily contained bug fixes.

In addition, the pre-jump / jump / landing issue reported in my Bento update #14 (and see BUG-18239) This issue appears to have been related to issues of animations repositioning the avatar pelvis (also the avatar centre) causing conflicts as Vir explained in the meeting.

Eye Bug

Coyot Linden demonstrates the eye bug
Coyot Linden demonstrates the eye bug

Unfortunately, the new project viewer has introduced a fair number of new issues, which the Lab is now looking into, However, one which (as at the time of writing) was awaiting a JIRA, was raised for discussion at the meeting by Medhue Simoni.

In short, the problem is that models uploaded using the latest version of the viewer which do not have eye positions / animation set for poses such as a default stand pose (so they use the default eye positions and will move naturally), have the eyes incorrectly positioned as soon as the avatar is worn.

The problem is exacerbated by the fact that even avatars uploaded using the latest version of the viewer ( which do display their eyes correctly can have the eyes reset incorrectly in a person’s view in the Reset Skeleton button is used. however, the eyes will also resume their expected position once any animation affecting them is played.

One possible culprit of the issue might be a new head slider, as discussed towards the end of the meeting.

Relative Bone Translations

A recent addition to the Bento project viewer is the ability to reset all bones in the skeleton. The idea is to correctly reset all bone positions in your view should an avatar deform when changing shapes. However, Gael Streeter has come upon situations where partial bone resets might be required, which prompted a discussion on the forum thread (see follow-ups here, here and here) and led to Tapple Gao offering a proposal (which also sparked further discussion in the thread) to address the issue via relative bones translations, which is also now a feature request.

While Vir Linden see the idea as a “nice to do”, it could entail some deep changes to the avatar system as well as having to extend the animation format; as such, it’s more likely to be something the Lab would consider for a “Bento follow-on” project rather than something they’d might try to implement at this point in time.

Leviathan Flux raises the matter of relative bone translations

Aki Shichiroji, wearing her Bento centaur settles down for the meeting
Aki Shichiroji, wearing her Bento centaur settles down for the meeting

However, there is a significant set of issues facing makers of mesh heads / faces, while could be resolved through relative bone translations which avoid making the shape sliders unusable (which would be the case if they relied on repositioning the facial bones).

A concern was raised that any changes made at this point in time risked the breakage of Bento content which is currently a work-in-progress for creators; however, most of those present at the meeting took the attitude better a breakage now if it yields an improvement,  than down the road, when breakage would be a much greater risk.

Vir’s suggestion is that there should be expanded discussion on the issues and proposals for alternative approaches so that a survey might be put together to determine what, if any, changes should be considered for implementation. A point of concerns with any such changes would be the impact on the avatar .LAD file, which would be a non-trivial item to update.

Vir Linden, Leviathan Flux and Cathy Foil discuss facial bones, pivot points and possible changes (note that this recording concatenates two separate conversations in the meeting into a unified whole)

Vir also suggested a JIRA feature request would be welcome, outlining the approach – what is considered to be required and the benefits it would offer humanoid mesh makers (given that a number of developments if Bento have been focused non-human avatars – although as Medhue Simoni pointed out, there could be benefits for non-human avatar makers as well).

Further discussion on facial bones, including having the mesh uploader modified so that .DAE files are made to observe pivot points, rather than ignore them

Vir’s concluding remarks on changing bone locations and re-iterating further discussions via the forum thread.

Other Items

Height issues / Ground Sits

There are still some issues around avatars standing on / in / over the terrain as a result of how animations, weighting, etc., are set. One of these  has been addressed in the latest Bento project viewer, others are being looked at. Vir also pointed at the potential to use Hover Height to adjust position / pose. One of the issues here is there are a number of different factors in the way avatars interact with the ground.

Maya / Mayastar Animation Exporters

Cathy Foil gave an update on Mayastar:

  • Aura Linden has completed the work on her .BVH exporter, which with export translations and rotations on all bones. This exporter will be made available to everyone, not just Mayastar users
  • Aura is also working on a .ANIM exporter (again in her own time, as with the.BVH exporter) for Maya
  • Cathy is still working on getting the bones hooked-up to the slider support in Mayastar  – but this is still going to take some time to complete.

Further Mesh Weightings / Maya discussions

A good part of the meeting was given over to the subject of weighting / skinning bones, approaches (notably when using Maya and Mayastar), together with further background information on the weighting cap of 110 bones per mesh, and general observations. For ease of reference, I’m listing this conversation as a series of audio files.

Leviathan Flux and Vir discuss mesh weightings, and Vir explains the 110-bone cap

Cathy Foil provides some suggestions for weighting meshes to bone with Maya

Cathy offers further suggestions for Mayastar users on understanding what bones are used, removing unused influences (which can be done from the skeleton itself)

Further discussion on skinning and weighting in Maya / Mayastar