MolTwister is an open source software package. It can aid in the construction of molecular systems used as input to molecular dynamics simulations. However, its primary purpose is to provide a collection of analysis tools for postprocessing of trajectories and data from molecular dynamics simulations. This includes calculation of density profiles, velocity auto correlation functions, radial distribution functions, dihedral distributions and more.
The software runs in a command line window and will act as an extension to the ordinary command line window, running in the background. Hence, an additional set of commands are available for creating and analysing molecular systems from the command line. Commands not recognized by MolTwister is sent for processing as a regular command (e.g., vim can be executed directly from within MolTwister). In addition to the extended command line, a 3D View window will display the molecular system being edited or created.
The command structure in MolTwister follows a simple structure. In the source code, each command is implemented as its own class that inherits from a base command class. A similar structure is also possible with sub-commands. From within the command class, access is given to the entrire state of the molecular system, including atomic positions, masses and force-field parameters. Hence, to implement a new command, copy a similar command class to the one that is to be created, rename it, register it in the command pool and implement its behavior. The class also contains the command documentation, thus providing a complete command implementation.