Dear all, Here is a single pdb file called modetest_14.pdb. It contains 6 structures: 1 protein MutS (only chain B) with 5 different conformations + another protein MutL (chains A and B). In Chimera, the protein with the 5 different conformations is displayed as model 0.1 to 0.5. The other protein is model 0.6. I would like to calculate the distance between the residue 239 of MutS chain B (for the 5 conformations) and the residue 169 of MutL chain A. I wrote this script which reports this error message: expected an indented block (scriptdistance.py, line 4) *from chimera import runCommand as rc rc(r"open C:\Program Files (x86)\Hex 6.3\examples\New Hex run_SL_250211\FirstRun_S_Ldimer\New_filtering\Eucl_Dist_S246-L297\Top solutions\SL0265B\dockLH248\NMA\Test\modetest_14.pdb") for i in range(1, 6): rc("distance #0.%d:239.B@N #0.6:169.A@N" % i)* May you tell me what is wrong? the script correctly opens the file so I suppose it is the python string #0.%d (intended to specify 0.1, 0.2,... 0.5)!? Thanks for your help Damien