Version 3.0 of ST-Sim, a spatially-explicit State-and-Transition Simulation Model framework, is now available for free download. This version adds a number of important features including: support for user defined probability distributions; enhancements to multiprocessing of model iterations and scenarios; the ability to display stock/flow model pathways; command line utilities for setting model inputs, running the model and exporting model outputs; and enhancements to link external models to ST-Sim.