In the animation process of a human-like 3D model, a skeleton must be specified to define the model’s surface deformation of its limbs. Nowadays the skeleton specification is hand made and very time consuming task. In this paper we propose a novel semi-automatic method for rigging a 3D model in an arbitrary pose using a skeleton defined in an animation datafile with no specific initial pose. First a skeleton is extracted from the voxelizated model, this skeleton is refined and transformed into a tree-data structure. Because the 3D model can be in an arbitrary pose, user interaction is required to select the five limbs correspondence (head, hands and feet), and finally a skeleton taken from an animation data file or a external source is adjusted to the geometric skeleton.