What is Project Bento?
Project Bento is an extension to the existing avatar skeleton to include many new bones, joints, and attachment points. These new bones support rigging and animation to provide the opportunity for a much wider range of avatar body types, facial expressions, and animations than is currently possible in Second Life.
The “classic” (default) Second Life avatar is not changing with the introduction of Project Bento, and all the existing joints in the avatar skeleton have not been altered. This means that all existing avatars and attachments will continue to function as designed and will not need to be updated. However, new mesh avatars and mesh attachments may take full advantage of the new joints and attachment points.
A video created by Second Life regarding Project Bento Project Bento
A summary of the new bones and attachment points:
New limb bones – For wings, additional arms, or extra legs.
Tail bones – Include your tail in avatar animations.
New hand bones – For finer control over hand animations.
New face bones – For complex facial expressions, and animating ears and antennae
New attachment points – Associated with the new bones. Accessorize your new limbs!
Creating content for Project Bento
Creating content for Project Bento is very similar to the current process for creating rigged mesh content. With the addition of more joints, there are some new limitations and differences.
Creating mesh content
As with all mesh content in Second Life, meshes for Project Bento must be created in an external modeling program such as Maya or Blender. These meshes must be exported as Collada (.dae) files for upload into Second Life. Meshes may be rigged to any of the bones or collision volumes of the avatar skeleton, but may not be rigged to attachment points. Meshes may be rigged to a maximum of 110 joints; this is less than the total number of joints in the new extended avatar skeleton, so you must make sure that your mesh does not list more joints than you are actually weighting to. If you need to rig to more than 110 joints, you need to model in more than one piece such that each piece does not exceed the limit.
Meshes may include overrides for the positions of some or all of the included joints to change the shape of the avatar. If you are wearing multiple meshes with different joint position overrides, only one of the meshes is chosen to provide the value for the joint offset. To minimize conflicts, define only as many joint position overrides as you need for each mesh. When uploading, you can choose whether to apply available skin weights and joint position overrides to the uploaded mesh. If skin weight or joint position override information is missing or invalid, these options are ignored.
Creating animations for the new skeleton in Project Bento is very similar to the process for creating animations for existing avatars, with more joints and a few limitations:
Animations may be uploaded in .bvh or .anim formats
Animations can be applied only to recognized avatar joints and attachment points, which are defined in “avatar_skeleton.xml”.
The total size of uploaded animations cannot exceed 120kb
The Avastar Bento Rig Explained
Animating In Blender With Avastar
Bento Hand Poses In Avastar
And a very help guide to get you started Project Bento Skeleton Guide