5.5. Bone Weighted Vertex (element)

5.5.1. Attributes

5.5.2. Description

This element defines a bone weighted vertex in a subdivision (a mesh). Bone weighted vertices are used for skinning and define the weights of the bones in order to control the vertex displacements.

The index attribute defines the index of the controlled vertex v_c in the tabvertexbone table. The k value of the size attribute defines the number of bones that control the vertex v_c.

This element must contain k pairs of numbers. Each pair is made of one integer, the bone index k_i, and one float, the weight w_i of the corresponding bone. The displacement of v_c is computed from the k transformations associated with each bone k_i as follows:

Equation 5-1. Linear Interpolation

5.5.3. Expected child

None.

5.5.4. Expected values

k pairs of numbers made of 1 integer value (the keypoint index) and 1 float value (the w weights of the transformation).

5.5.5. Example

The example below defines the 41st bone weighted vertex that is controlled by the 1st, 2nd, and 4th bones. Its transformation is the center of gravity of the vertices obtained by applying separately the three transformations of the 1st, 2nd, and 4th bones to the vertex.

<vertex index="41" size="3">
  1 0.3333       2 0.3333        4 0.3333
</vertex/>