Hello, What is the best way to get center of mass Jacobian? My best technique is to use the following expression, using the fact that x_COM = sum { mi/M*x_com_i } . Is there any better way to get this ? Code: // --------------------------- COM Jacobian mjtNum mi; mjtNum *jacp_i, *jacr_i; mjtNum *jacp_COM = new mjtNum[3 * (m->nv)]{}, *jacr_COM = new mjtNum[3 * (m->nv)]{}; for (int i = 1; i < m->nbody; i++) { // exclude i=0 the world body mi = m->body_mass[i]; mi = mi / m_tot; mj_jacBodyCom(m, d, jacp_i, jacr_i, i); mju_addToScl(jacp_COM, jacp_i, mi, 3 * (m->nv)); mju_addToScl(jacr_COM, jacr_i, mi, 3 * (m->nv)); } //------------------------------------------