skin 

The controller element may contain either a skin element or a morph element.

Element Information

Model

bind_shape_matrix{0,1} , source{3,unbounded} , joints , vertex_weights , extra*
Children: bind_shape_matrix, extra, joints, source, vertex_weights

Attributes

QName Type Fixed Default Use Inheritable Annotation
source xs:anyURI required 
The source attribute contains a URI reference to the base mesh, (a static mesh or a morphed mesh).
This also provides the bind-shape of the skinned mesh.  Required attribute.

Source 

<xs:element name="skin" type="skin_type">
  <xs:annotation>
    <xs:documentation>The controller element may contain either a skin element or a morph element.</xs:documentation>
  </xs:annotation>
</xs:element>

Sample