[Chimera-users] Generating trajectory of a user-defined plane

Hi, I am interested in measuring the deviation of an helical segment with respect to the initial structure in a GROMACS trajectory. I have already uploaded my *.tpr and *.trr files into MD Movie and have defined a plane through the helical segment within the initial structure. Is it possible to define another plane through the same helix and track the intersection angle throughout the trajectory? Thank you, Lili