How to use the meshcat.transformations.translation_matrix function in meshcat

# visualize all valid contact forces
        for contact in self._contacts:
            # Compute pose of contact cylinder `C` in world frame `W`.
            R = np.zeros((3, 3))
            magnitude = np.linalg.norm(contact.info.contact_force())
            y = contact.info.contact_force() / magnitude
            R[:, 1] = y
            R[:, 0] = [0, -y[2], y[1]]
            R[:, 2] = np.cross(R[:, 0], y)
            X_WC = np.eye(4)
            X_WC[0:3, 0:3] = R
            X_WC[0:3, 3] = contact.info.contact_point()
            # Scale cylinder
            visual_magnitude = self._get_visual_magnitude(magnitude)
            T_scale = tf.translation_matrix(
                [0, visual_magnitude / 2, 0])
            T_scale[1, 1] = \
                visual_magnitude * self._force_cylinder_longitudinal_scale
            # - "expand" cylinders to a visible size.
            T_scale[0, 0] *= self._force_cylinder_radial_scale
            T_scale[2, 2] *= self._force_cylinder_radial_scale
            # Publish.
            vis[prefix]["contact_forces"][contact.key].set_transform(
                X_WC.dot(T_scale))

        # update time
        self._t_previous = t

+ np.array(start_ray.direction) * short_length
                    )
            colour = wavelength_to_hex_int(nanometers)
            ids.append(self.add_line_segment(start, end, colour=colour))

            if baubles:
                event = start_part[1]
                if event in {Event.TRANSMIT}:
                    baubid = self.get_next_identifer()
                    vis[f"exit/{baubid}"].set_object(
                        g.Sphere(bauble_radius),
                        g.MeshBasicMaterial(
                            color=colour, transparency=False, opacity=1
                        ),
                    )
                    vis[f"exit/{baubid}"].set_transform(tf.translation_matrix(start))

                    ids.append(baubid)
        return ids