Dear all,

I am interested in visualizing the major and minor axes of inertia of a ligand in a PDB structure by using UCSF Chimera. Once I calculate the axis of inertia by entering in command line:

measure inertia sel

I obtained the following info (in reply log):

v1 =  0.985 -0.173 -0.013   a =  6.079   r1 =  2.103
v2 = -0.086 -0.553  0.829   b =  4.564   r2 =  2.765
v3 = -0.150 -0.815 -0.559   c =  1.127   r3 =  3.400
center =   38.682   56.595   62.547

However, I do not still know:

1- What are the major and minor axes of inertia? This info is given by the "a/b/c" or "r1/r2/r3" values?
2-How can I visualize the major and minor axes of inertia as planes (or arrows)?

Thanks in advances for your help.

Best regards,


Andrés Felipe Vásquez J., BSc, MSc.
PhD candidate in Chemical Engineering
Universidad de los Andes
Bogotá, D.C., Colombia 
Carrera 1 #18A-12, Of. ML-754(26)
+57 1 3394949 Ext. 1747