Maps of relative orientations between the orientation angle, θ, of the selected structures and the projection of V_M onto the plane of the sky, for the Gaussian model in which V_M0 is set to 0. The mask described in Sect. 4.2 is applied. We show the two fields of view presented in Fig. 17: Taurus (left) and Chamaeleon (right) molecular complexes. The white (black) structures correspond to alignment (anti-alignment) between the projection of V_M onto the plane of the sky and θ. This figure shows that projection effects cannot account for the elongated and coherent structures in the relative orientation maps of Fig. 17 (right).