Category: SL User Group Meetings

The following notes and audio were taken from the weekly Bento User Group meeting, held on Thursday, October 13th 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

The Bento viewer is now on its third version as a release candidate (version 5.0.0.320160 at the time of writing). It is performing well crash-wise in comparison with the current release viewer, so the hope is – bugs allowing – it might not be too long before the viewer moves up to release status.

The first of the bugs mentioned by Vir in the audio is that the scale locking capability recently added to disable shape sliders from having any influence over joint positions has been reported as working intermittently at times. Vir is still looking into this.

The second is a report instance of pre-Bento content being deformed when viewed on the Bento viewer – see BUG-40672.

The problem appears when a sub-mesh contains bad joint position overrides for various joints that the model is rigged to. Prior to Bento, these joint position overrides were not applied, because the Lab was enforcing a 20-joint minimum: if a sub-mesh was rigged to fewer than 20 joints, then it was not treated as rigged, and the joint positions were ignored.

For Bento, this restriction has been relaxed to make it easier to produce meshes only affecting part of the avatar (wings affecting wing joints positions, head that affects only head join positions, etc.), making it possible to “mix and match” different meshes. Unfortunately, it also means that any model with “bad” (but previously “invisible”) joint positions defined may now appear deformed.

Reverting the viewer to its previous behaviour is not seen as optimal, because of the potential to break some Bento models and make the extended skeleton less useful (no more mix and match of meshes). Similarly, it is currently unclear as to how much content might be affected if the updated behaviour is retained, so the Lab is still considering what to do.

Makers of pre-Bento mesh avatars are asked to check BUG-40672 and then test their avatars using the current Bento viewer to see if similar issues manifest themselves. The most direct way to “fix” things is for affected content being re-uploaded with the bad joint positions removed, or by adding an animation to fix the joint positions after the fact (assuming said animation doesn’t conflict with others the model is using). Of course, if the model does not require joint positions at all then the option could also simply be unchecked at upload time.

Animating Hands

A complex discussion has been unfolding on the discussion forum concerning animating hands (from around page 122 onwards), and which also encompassed a part of the user group meeting (in text). It’s a convoluted subject involving several elements, of which perhaps the most important thing is understanding how best to animate hands.

To try to address this, Cathy Foil has produced a comprehensive video on hand animations, which anyone developing mesh hands for Bento may find informative and helpful, and so is embedded below.

Cathy also provided some hints and tips during the meeting.

Feet

There has also been forum discussion on feet. Bento doesn’t add and further joints to feet, and there are no plans to change the rig specifically to a support for animating feet. However, as Vir pointed out, there are more joints than the system avatar does not use – mToe and possibly mFoot – which might offer a degree of flexibility for mesh creators. If these are used, a point to keep in mind is that they are not used in the avatar height calculations, so some unexpected results my occur.

Other Items

Bounding Box Clipping / LODs

A non-Bento issue which can be frequently seen at Bento meetings due to the number of meshes being worn is that of bounding box clipping – part of the avatar appears to vanish as a camera is pulled back.

This generally occurs when the viewer is operating at the limit of its imposter avatars setting, and a conflict occurs trying to both display the avatar mesh (which the viewer will try to render at a united LOD (level of detail) whilst also trying to switch to displaying an avatar as an imposter. It can be overcome by setting the imposter slider to No Limit in Preference > Graphics.

While fixing this issue is not part of Bento, it raised the subject of why LODs aren’t used rather than the imposter setting. Vir explained that one reason is this idea that the viewer will try to render avatars and their attachments at a high LOD, rather than stepping down through LOD models, as is the case with in-world mesh objects. Another isse us that many creators tend to only use high LOD models, and incentivising people to use the LOD system correctly isn’t easy, although there are tools (e.g. Decimator in Blender) which help in the creation of LODs for models.

As the whole issue of rendering and associated costs and calculations is now being looked at by the Lab, changes might be forthcoming to help with matters – time will tell on that.

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)

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)