[chimerax-users] Angle between an axis and a plane

Dear All, I am trying to calculate a set of angles between pairs of axes and planes. Example: sel #1/B:348,1052 @ca; define axis sel; sel #1:1052 @ca; define plane sel; angle #1.3 #1.4 My problem is that the angle is always reported positive, no matter whether the axis goes "up" or "down" from the plane, when "up" and "down" are defined relative to the orientation of the molecule. Is there any way how to distinguish between these two cases automatically? Thanks very much in advance. Best regards Sasha Zahradnikova