![]() ![]() So in practice your mesh will only need weight groups for the bones which are used for its animation (for example “ankle” and “knee” bones for a boot made for OpenSim and similar)Īctually it also turns out that a bone weight map typically is populated mostly with 0.0 entries, because of the same reason as mentioned above: An arm bone will not take control over a part of the mesh near the foot, etc… A bone will typically only need weights for nearby vertices. For example when you rig a pair of boots, then the entire set of upper body bones will not have any influence on the shoe, and the weight groups for the remaining bones can be omitted, because they are empty anyways. In practice it is possible that a mesh is only influenced by a small subset of the skeleton bones. And each weight groups will contain exactly one weight for each vertex of the mesh… So when you create the weighting for a character, then (in theory) you will end up with exactly the same amount of vertex groups as you have bones. In Blender the weight maps are stored in vertex Groups, where the vertex Group and the corresponding bone have the exact same name. Thus when the character’s skeleton moves, then the character’s mesh moves along with the skeleton according to the sum of all influences defined in the entire set of weight maps. So actually we need to define a mapping between each bone of the skeleton and each vertex of the mesh, that is: we define one weight map for each bone of the character. Any value in between 0 and 1 indicates the amount of influence on the corresponding vertex.A value of 1.0 means: the vertex moves in parallel to the bone.A value of 0.0 means: whatever the bone does, it does not affect the vertex.It can be expressed as a value in the range where: The influence of each bone on the mesh is defined separately for each vertex. Each of the bones can influence the entire mesh when it is moved around. ![]() The skeleton is a set of bones (26 for OpenSim and similar). So, instead of defining many separate mesh models, we create an easy to handle abstract model of our mesh, the skeleton. we would end up with tens, even hundreds of separate meshes just to animate one single character. However that is not a practical solution. The straight forward approach to reach our goal would be to model each pose separately, and later use a sequence of mesh models to animate the character. ![]()
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