Abstract. We present a novel armature structure for 3D articulated shapes, called SBall short for ‘skeletal balls’, which includes two parts: a one-dimensional skeleton and incident balls. Our algorithm mainly focuses on constructing the armature structure. This structure is based on an approximation skeleton which is homotopy equivalent to the shape. Each ball in the structure connects a skeletal joint and an interior region of the shape. The boundary vertices on the shape surface are attached