SkeletalMesh is geometry bound to a hierarchical skeleton of bones which can be animated for the purpose of deforming the mesh. Skeletal Meshes are built up of two parts; a set of polygons composed to make up the surface of the mesh, and a hierarchical skeleton which can be used to animate the polygons. The 3D models, rigging, and animations are created in an external modeling and animation application (3DSMax, Maya, Softimage, etc).