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This script is used to analyse geometrical properties in MD trajectories. One measured variable can be specified at commandline, multiple variables can be defined in an input file.

It works not only with atoms, but also with groups of atoms. In the groups, their center of mass is used as the coordinate unless specified otherwise.

Measured properties:

Commandline options

measure [options] trajectory_file

Input file, expressions

Input file is a text file that can contain multiple expressions to be measured, one per line. Blank lines and lines starting with # are ignored.

Basic expressions have format:

expression_type(selection; selection; ...)

or they can be named:

name = expression_type(selection; selection; ...)

The expression types are: