functions in pl3d.i - o

    orient3, phi, theta  
 or orient3, phi  
 or orient3, , theta  
 or orient3  


Set the "orientation" of the object to (PHI,THETA).  "Orientations"  
are a subset of the possible rotation matrices in which the z-axis  
of the object appears vertical on the screen (that is, the object  
z-axis projects onto the viewer y-axis).  The THETA angle is the  
angle from the viewer y-axis to the object z-axis, positive if  
the object z-axis is tilted toward you (toward viewer +z).  PHI is  
zero when the object x-axis coincides with the viewer x-axis.  If  
neither PHI nor THETA is specified, PHI defaults to -pi/4 and  
THETA defaults to pi/6.  If only one of PHI or THETA is specified,  
the other remains unchanged, unless the current THETA is near pi/2,  
in which case THETA returns to pi/6, or unless the current  
orientation does not have a vertical z-axis, in which case the  
unspecified value returns to its default.  
Unlike rot3, orient3 is not a cumulative operation.  
Interpreted function, defined at i/pl3d.i   line 127