Category: SL Tech

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.

Continue reading “Project Bento User Group update 2 with audio” →

Useful Links

• Project Bento overview – this blog
• Project Bento Knowledge Base article – Linden Lab
• Project Bento Skeleton Guide – Linden Lab
• Project Bento Testing – Linden Lab
• Project Bento discussion forum

The first public user group meeting for Project Bento took place on Thursday, January 7th 2016, marking the start of what will be a regular event, although the exact frequency, particularly in terms of day and time, may vary, at least initially.

The purpose of the meeting is to provide an open forum for more direct and real-time conversations between the Lab and content creators about Project Bento than can perhaps be achieved through forum posts, etc. This, and the reports which follow from it are intended to provide a synthesis of these meetings, together with relevant audio of discussions and feedback, where appropriate. My apologies for the quality of the audio in places; these was partially the result of recording over voice and also due to the audio strength dropping out on me quite frequently.

Translation vs. Rotation

As I’ve previously reported, there has been an ongoing discussion about providing bone translation rather than just rotation in order to better handle facial expressions (see BUG-1090, “[Bento] A formal method of bone-translating animations is vital for the creation of proper facial expressions”), with the initial disallowing of translations within Bento (where they had previously been possible by means of a workaround) being a particular point of contention.  Medhue Simoni was one of those particularly concerned at the lack of available translation capabilities, and as I noted in my coverage of the 100th Drax Files podcast, he has produced a fairly comprehensive video explaining the issue.

Given the amount of conversation that has been generated, it should not  be that surprising to learn that this was the first item up for discussion in the meeting. In particular, Vir announced that the Lab has revised its thinking on the matter pointing to a Bento forum posted providing more of the Lab’s original concerns. So with this change, animations using translations can now be uploaded to most regions on Aditi.

Vir on the rethink concerning allowing bone translations

So does this mean translations will be allowed going forward? Vir was cautious in his reply, noting that nothing about Bento will be finalised until such time as it goes to the main grid, so there is no definitive decision on the matter at present. However, based on the way things are going, it would seem likely that translations will be enabled and there is nothing the Lab currently has planned which might cause them to be disallowed. However, Vir did warn that were this to be the case, there may be bugs / limitations in how they work.

Vir on whether or not translations will be allowed going forward

Stretching and Scaling Bones

The current mechanism for stretching / scaling bones is via the shape slider, and Vir indicated that it is not likely that the Lab will be moving to support scaling in animations as a part of this phase of Bento, although they might revisit doing so at some point in the future (without any guarantee they would).

As a part of the explanation for why this is the case, Oz indicated that the Lab’s belief in approaching Bento was that for most non-human avatars and shapes, their expectation was that creators would do the basic repositioning of joints as a part of the mesh prior to upload, and then adjust them as needed, and so the need for translation  would be marginalised.

However, as several of those present at the meeting pointed out, effectively “baking” positions into a mesh in this manner prior to upload is itself limiting, and translations can help handle odd glithes in the avatar shape which can occur. Given this, and  the shift in stance on translation mentioned above, Oz indicated he’s very interested to hear back from people on what might be considered “best practice” for handling bone repositioning, scaling, stretching, etc.

Vir and Oz on scaling and stretching bones and the Lab’s initial approach to Bento

Avatar Deformation and Resetting

One of the things the Lab is trying to achieve through Bento is a means of more reliably providing a mechanism by which avatars suffering from deformations as a result of rigged meshes, complex shapes, etc., can be reliably restored.

As Vir noted in the meeting, the Lab has been working on trying to make mesh positions behave better, but there is still a lot going on under the hood, such as changes made by sliders or attachments or animations, or a combination thereof,, the initial values defined by the skeleton, etc.,  which can influence the overall shape / appearance in an unpredictable order which can leave someone in a difficult to resolve state.

In particular, and as stated by Oz, the Lab would like to be able to offer the capability that if a user experiences deformations as a result of running animations, they can be reliably reset to a default position that includes and joint position movements implied by any mesh attachments worn at the time the issue occurred (with the exception of those implied by animations).

To this end, he and Vir urged people to file bug reports on any issues of deformation they encounter when using the Bento project viewer (as well as any other issues they encounter), even if the issue has been previously encountered prior to Bento but has remained unresolved, and to provide specific examples of the problem with related models, etc., so that the Lab can use the project to attempt to investigate and resolve as many issues of this kind as they can. The Lab cannot promise that everything will be fixed, but by the same standard, it shouldn’t be assumed that just because something hasn’t been addressed thus far, effort won’t be put into trying to see if it can be resolved.

Vir and Oz on bug resolutions and seeking a means to consistently reset deformed avatars

Continue reading “Project Bento User Group update 1 with audio” →