av->id_board = skeleton_bone_id( sk, "board" );
av->id_wheel_l = skeleton_bone_id( sk, "wheel.L" );
av->id_wheel_r = skeleton_bone_id( sk, "wheel.R" );
av->id_board = skeleton_bone_id( sk, "board" );
av->id_wheel_l = skeleton_bone_id( sk, "wheel.L" );
av->id_wheel_r = skeleton_bone_id( sk, "wheel.R" );