From: Raul Araya (
Date: Tue Jan 19 2021 - 09:21:39 CST

Dear VMD users

I'm using orient and tcl to compute the angle between the principal axes of
two protein domains. However, I'm running into some issue I cannot solve.
Sometimes the X or Y projection of the vectors flip (change sign) and thus
the computed angle also changes. How can this flipping be prevented or

Raul R Araya-Secchi
Postdoctoral researcher
X-ray and Neutron Science,
The Structural Biophysics Group,
Universitetsparken 5,
2100 CPH, DK.