voXSim is an amelioration of Fiberfox which, contrarily to the latter, allows its users to control the white matter bundle generation through the command-line interface (CLI). Also, Simulation Generator offers a high level Python API to voXSim. There are no equivalents for Fiberfox.
voXSim and Simulation Generator are both developed by Alex Valcourt Caron from the Sherbrooke Connectivity Imaging Laboratory (SCIL).
The .fib file format is
a legacy VTK file format. More
information can be found on the VTK website.