A computer-implemented method for simulating a human or animal body taking a posture, comprising the steps of: a) providing a model (AV) of said human or animal body, including a skeleton comprising aplurality of bones articulated by rotational joints to form at least one kinematic chain; b) defining a starting position and a starting rotational state for each rotational joint of the skeleton, atarget point (T) and a bone, called end bone, of a kinematic chain, called active kinematic chain; c) for a set of bones of the active kinematic chain, including the end bone, defining at least one axis (GZ) having a fixed orientation with respect to the bone; d) determining a first posture of the body by performing bounded rotations of a set of joints of the active kinematic chain; and e) determining a second posture of the body by iteratively by performing bounded rotations of a set of joints of the active kinematic chain in order to direct a selected axis (GZ) of the end bone toward the target.