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