Category: SL Tech

The following notes and audio were taken from the weekly Bento User Group meeting, held on Thursday, September 29th at 13:00 SLT at the the Hippotropolis Campfire Circle. and chaired by Vir Linden. 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.

RC Viewer and Scale Locking

The next release of the Bento RC viewer should be appearing soon. When it does, it will have a couple of updates:

Slider Scale Locking

At the last meeting, Vir requested feedback on the proposed ability to effectively make joints in a mesh “slider proof” by overriding the scale as well as position in uploaded mesh models, as seen in the proof of concept viewer put out at the start of September.

The option has now received positive feedback, and will included in the next RC update. It will comprise a check box which, if checked will lock joints against scale changes, and thus the sliders affecting the joint will no longer influence it. Leaving the box unchecked for the joint will allow scale changes.

Performance optimisations

There has been one noticeable “hot spot” of viewer performance degradation as a result of all the new Bento joints. This has been sufficient for the Lab to make some changes which should help improve FPS for users when in a region with a lot of rigged mesh.

Going to Release

The question on when Bento will reach a release status tends to come up at every meeting, and the answer remains the same. Bento’s promotion to release status is dependent on a number of factors, including:

• The viewer’s crash rate compared with the current release viewer and other RC viewer in the release channel
• Whether exposure to a wider audience of users uncovers non-bento bugs or regressions which require additional fixing
• Relative priorities between Bento and other projects.

However, there have been few Bento-specific bugs raised against the RC viewer, and while it still requires time as an RC as changes are still being made, Vir’s hope is that it will be weeks rather than months until the viewer is promoted to release status (bugs and other priorities allowing, as noted.

Joint Position Locking

A joint’s position can be locked from slider influence by setting a custom position for it. However, the slider’s influence isn’t completely disabled, as a change to scale can still have influence. For example, if the scale of a parent join is changed, it can influence where a child joint appears, even if the child has a custom position set (hence one reason for the scale locking. However, there has been a suggestion that joint position locking may not be working smoothly, so Vir is interested in hearing about situations where this might be the case.

The question was asked in joints could be locked from within Second Life – that is, after upload. the short answer to this is no, as it would require a significant amount of reworking which falls well outside of the scope for Bento.

Animation Priorities And Formats

As all SL animators know, the platform supports two animation types: .BVH and .ANIM. The differences between them, in essence, is that .BVH is a format which pre-dates Second Life. During the upload process, an attempt is made to process the .BVH file to make it more efficient. The .ANIM format is more of an internal format for Second Life, and bypasses all the processing common to .BVH files; all the settings are already baked in, including the priority.

Generally speaking, the priority in which animations play is based on their priority; those animations with a high priority than other will take precedence in playback. If to animations with the same priority are called, it can be indeterminate as to which may play first. There have been some proposals to make this more deterministic, but it is a non-Bento effort, if it is being actively pursued.

However, if using the .ANIM format in Blender, it is possible to set the animation priority on a per joint basis, prior to exporting for upload to Second Life – although it is not clear if the Second Life .ANIM format supports a per-joint field for prioritising animations. Also, all of the options available in the .BVH uploader for Second Life are available for .ANIM files from within Blender / Avastar, and can be set from there prior to export.

Maya also has a native .ANIM format, but it is important to note that this is not the same format as the Second Life .ANIM file, and it is not  compatible with Second Life.

Other Items

Mixing and Matching Bento Parts

One of the aims with Bento is to allow users to mix and match Bento parts. So, for example, if you have a Bento elephant, you might in theory be able to get a set of Bento wings and add them to become a flying elephant. To achieve this, a Bento mesh no longer has to define positions for all the joints in the skeleton – only those it actually uses need to be defined.

However, this still means customers must be aware of the joints being used by different mesh models to avoid potential conflicts. Again, if the elephant mentioned above uses the wing bones to animate its ears, that’s going to conflict with the use of wings using the same bones  – and yes, I’m avoiding Dumbo and his ear-flapping flying for the purposes of this example! 🙂 ).

One way to avoid this might be for creator to document the joints they’re using in their mesh models when selling them (e.g. in the Marketplace listings, on their vendor boards, etc). But quite how this might work in practice remains to be seen – and will largely rely on the community to consider matters.

MayaStar Update

Cathy Foil has reached a point of getting all the sliders working with the all of the bones, although some are not yet working properly. She hopes that MayaStar will be updating a in the next couple of weeks. She also reminded people that Aura Linden is, in her own time and unpaid, writing an exporter for MayaStar for .ANIM files. This will be provided as an open-source project.

Bento Follow-up?

After the main meeting had finished, Cathy Foil indicated that she and Matrice had discussed a possible follow-up for Bento with Vir, which he was positive about. This would be to add a further appearance slider which would allow an avatar to be correctly / proportionally scaled larger or smaller.

This would apparently be a relatively simple addition, although work would also have to be put into correctly scaling walks, runs and flying to avoid things like Mach 5 tinies roaring across a region because the scale of their steps remains unchanged (the upper and lower limits of avatar size would also need to be defined). Given the potential benefits of such a slider – more efficient land use as avatars could be more easily scaled down to make use of smaller spaces, etc. -, it could also be a useful task for one of the few remaining slider slots which are available.

The discussion included the idea of using animations or even a file (/script) to define avatar scale, with Cathy indicating that animation scaling was ruled out early in the project on the grounds of cost, and that Vir was unsure of a way to easily allow file-based avatar scaling.

Next Meeting

Due to the Lab’s monthly internal meeting, which conflicts with the Bento meeting, the next Bento User Group meeting will be on Thursday, October 13th.

Addendum

Those interested in the Bento mega-wolves by Medhue can now obtain them through the Marketplace, and read about them on Medhue’s blog. You will require a Bento-enabled viewer to render them correctly. With thanks to Whirly for the pointer.

Additional Links

• Project Bento testing page (wiki)
• Avatar body size (wiki)
• Bento Skeleton Guide (wiki)
• Project Bento user group page
• Project Bento discussion forum
• Project Bento coverage in this blog (including weekly user group meeting updates)