The second public user group meeting for Project Bento took place on Thursday, January 14th 2016, continuing discussions on the new avatar skeleton extensions for Second Life. The following is intended to provide a summary of the discussion, together with audio excerpts from the meeting. It is not, however, intended to present a full transcript.
Additional / Alternative Bones and Experimental Region
The experimental region for those wishing to try additional / alternative bones (see my report from the first Bento public UG meeting), is now available on Aditi at BentoExperimental1. It had been misbehaving when first set-up, but is now thought to be running smoothly.
One concern among content creators who are already working on Bento is the potential for additional / alternative bones to be disruptive, that has they are added, it will break content being used for ongoing testing of Bento, particularly for those working on complex, multi-limbed avatars.
Vir pointed out that while the Lab don’t want to necessarily add to the workload in testing new bones, it’s better to look at possible additions / alternatives sooner rather than later, and accept test content may break if charges are to be made in the near future as a part of developing the project.
He also pointed out that so far, the focus on additional / alternative bones has been on the face, which shouldn’t have any impact on those working with the new wing bones, etc. Although that said, there is no limitation on proposing additional bones for wings, legs, etc., even if they do prove a little disruptive at this point in time.
End dates and Selecting New Bones
Currently, the Lab hasn’t determined any date by which proposals for additional / alternative bones must be made, or the process by which any of the proposals might be adopted. However, creators are encouraged to use the experimental region to develop models as demonstrations sooner rather than later.
While it is not 100% certain, given there is currently no clear consensus as to what additional / alternative bones might be seen as a priority among those proposing them, the Lab is considering making any potential selection the matter of a poll at some point in the future, and make any determination based on that.
Vir also indicated that ideally, the Lab would like to make as few further changes to the skeleton as possible, and so may opt to add additional bones as a single pass in the viewer, rather than gradually adding them (which might also cause problems when testing, due to the repeated risk of breaking test models as noted above). Either way, the code will be stabilised well before any attempt is made to move Bento to the main grid, in order to ensure that people have adequate time to test things and to allow TPVs sufficient lead-time to integrate the Bento code into their offerings so that they can support it when it is deployed.
IK Bone Issues
A problem has been noted within the skeleton between the new toe bones and the IK (inverse kinematics) bones which connect the avatar physically to the world. The latter are focused on the foot bone in the avatar skeleton, with the result that when the new toes bones are used to animate the avatar (as might be the case with digitgrade legs), a conflict with the IK bones can occur, causing the animation to go awry. It doesn’t happen all the time, but when it does, it is very noticeable.
Exactly what can be done to deal with this is open to question; Vir’s initial thoughts were to consider changing the logic so that IK bones are focused on the toe, rather than the foot. Alternatively, Oz suggested adding a new flag which would allow a mesh to indicate it does not want a joint manipulated by IK, and idea which was seen by some creators as offering greater potential for use.
To help the Lab better understand issues and gain a thorough insight what might be required in order to address issues where they can, a request was once again put forward for very concise in-world examples and models.
Both Oz and Vir concurred that any large-scale alternations to the IK chain, such as extending it to include the new bones is unlikely, due to the risk of breakage with existing content on the main grid and due to the additional overheads it will place on Bento in terms of testing, lead times, etc.