Binding

Binding (Assign Armature)

[PS Showtime url=”/wp-content/uploads/2012/08/map_skinning.png”]

After you have modeled your mesh (Character or Attachment) the next step towards animating your work is skinning the mesh. This is basically the process of attaching the mesh to a rig (Armature) and defining how exactly the mesh gets influenced by the Armature’s Skeleton. Avastar’s Skinning Panel provides a convenient starting point for this work.

Basic Preparations

Cleaning up the Mesh

Ensure that the mesh does not have any implicit scale or rotation from one of its parent objects. This issue typically happens when your mesh is still parented to another object (Mesh, Rig, Empty,…) which has a scale and or rotation defined.

Easy Fix (recommended)

Select the Mesh
Object -> Parent -> Clear and Keep Transformation
Object -> Apply -> Rotation and Scale

Advanced Fix (not recommended)

Select the parent of the Mesh
Apply Scale and Rotation
Do the same for the Parent’s parent and so on…

This avoids unexpected behavior and it ensures that your object can be bound to another rig without distortions.

Hint: It is in general best to have as few objects as possible in your visible layer. So you best move all objects into another invisible layer which are not directly involved in the bind action. This ensures that you keep track of what happens.

Reposition and Bind

You prepare the binding step as follows: First you align your new mesh attachment as good as possible to the Avastar character. Then you select both the armature and the new mesh attachment:

Go to Object mode
Select the attachment with RMB. If you want to bind multiple new attachment at once, select all of them now (order does not matter).
SHIFT RMB select the Avastar Armature.

Now you have selected the Rig and all mesh attachment which shall be bound to the Armature.

Note: If you are familiar with Blender, then you can simply parent the selected meshes to the armature (using Object -> Parent -> Armature Deform).

The Skinning Panel

For your convenience we have added a Bind to Armature button within the Skinning Panel in the Tool shelf. This button and its associated properties only appears when you have selected at least one Mesh and one Avastar Armature as described above.[break] The Weight Option allows to select from where the initial weight maps will be generated. The 5 check marks below the Weight Option provide more basic fine adjustment (see below for details).

Note: You can not expect that this function automatically creates optimal results! Hence you must be prepared that in most cases the resulting weight maps have to be fine adjusted manually. Please look at the Create an Attachment tutorial on this website.

The Skinning Panel Options

Weight:

This Property defines from where the Bound meshes will get their initial weights. We provide 4 Weight sources here:

Meshes: The weight maps are copied from all Meshes which are already assigned to the same armature and which are currently Visible in the 3D viewport.

Hint: If you have hidden all Meshes, then you will get an error message from Avastar that it could not find any weight sources.

Bones: The initial weights are created automatically from the Bones. This function is provided by Blender ( “assign automatic from Bones” ) We added this here for convenience.

Hint: The automatic weight assignment sometimes runs into an issue where it can not find solutions for one or more vertices. This is typically due to intersecting and/or unconnected mesh parts in your object.

Empty: Weight maps will be created, but not populated (no weights will be calculated). If the mesh already has weight groups assigned, then these groups will be preserved. You want to use this option when you later plan to assign weights manually.

This option will only create missing weight maps. Weight maps which already exist in the Mesh will not be touched and kept as they are.[break] Hint: The Empty option should be rarely used. In almost every case you will be better with the next option.

Keep: No weight maps will be created. If the mesh already has weight maps they will be preserved. You want to use this option when your mesh has already been weighted, and or when you want to manually weight your meshes.

This option is almost identical with the Empty option, only you will not be cluttered with empty weight Maps. Since weight maps are created on the fly during your weighting activities, in almost every case this option is the best to use when you intend to create your own weight maps.

Note: Directly after a mesh was bound to an Armature, you will find this section replaced by a weight Generator section from where you can regenerate your weights completely or partially at any time. For more details see in the skinning help section.

Clear Weights

The weight generators only replace weights. Hence if your weight maps already contain weights for whichever reason, then all weights which are not replaced by the weight generators will be kept as they are.

When this option is selected, then Avastar will first remove all weights from affected weight groups so that the weight generators will operate on fresh weight groups.

Selected verts

If this option is checked, then only the currently selected vertices will receive mesh weights.

With Eye Bones

By default the Eye Bones are considered to not influence any other parts than the eyes them self. this avoids weird weighting results in the face where eyes and meshes typically intersect partially, thus the weighting generators often create bad results.

When this option is set, the eye bones are treated by he weight generators exactly like all other bones.

Interpolate (only available with Weight:Meshes)

If this option is checked together with the “with weight copy option”, then Avastar subdivides the source meshes (meshes attached to the armature and currently visible) to get a smoother distribution of the weight values on the target mesh.

Alter to Rest Pose

The current Pose of the Armature is also taken into account (see note below). It is mandatory that either the mesh has already been weighted or either the weight:Meshes or Weight:Bones option is enabled (see above).

Note: Avastar will reject a mesh that is not fully weighted when this option is enabled.

What is Alter mesh to Rest Pose ?

This video is about what the Alter to Restpose feature actually does for you[break] Below you find some explanation.

In principle this option does the equivalent of the following procedure:

The current pose (“mesh pose”) is made the armature’s default pose.
The mesh is parented to the new default pose
The pose is set to the actual T-Pose (and the mesh gets bent into T-Pose)
The mesh is frozen (pose applied and mesh unbound from the armature)
The armature’s default pose is set back to T-Pose
The mesh is parented to T-Pose.
When now the armature is posed into the original “mesh pose” then the mesh looks exactly like it looked when it was not yet parented.

Avastar does not step through the above process, but instead calculates the needed modifications and applies them directly to the mesh, then parents to the Avastar Rest pose (T-Pose).[break] Note: Since Avastar is modifying your mesh directly, you should use this tool with caution.

When your mesh fits well to the Avastar mesh, then you probably want to initialize your weight maps by setting the Weight option to “Meshes”.
Only when you have to pose the Avastar in order to get a good alignment to your mesh, then you will also want to enable “Alter Mesh to Rest Pose”.

Note

When the option “Alter mesh to Rest Pose” is enabled then your mesh will be altered on vertex level. The mesh will actually be bended into the Avatar Rest Pose (which is the T-Pose). Such that when the current pose gets applied later then the current shape of the mesh is almost exactly preserved.