Vensim 6.4 Released.

Get It

Vensim 6.4 is available for download or purchase in the Vensim Store .

Upgrades are easy – just visit the download page and enter your license key information.

  • If your maintenance is current, you can download immediately.
  • If you don’t have a current license, you can extend your maintenance easily – just follow the Upgrade link that will be generated.
  • Can’t find your license? Need other options? No problem – contact sales at for help, volume quotes and other information.

PLE is always free for noncommercial use, and the Model Reader is free for redistribution of any model.

What’s New?

Optimization improvements
o All optimization settings, including MCMC, stochastic optimization and extended payoff types are now available directly from the user interface. See the sections on Payoff Definitions and Optimization for more details.
o Payoff reports have been improved
o A new payoff type permits elements that contribute to Kalman filter updates but not to the optimization payoff
o Payoffs now skip points with NA values of model variables
o Minor bug fix to prevent randomization of MCMC internal processes
o Faster payoff computation
o Kalman filter stability has been improved, particularly for models with many measurements and few states
Sensitivity simulation improvements
o The VECTOR distribution has new options for testing only endpoints
o Improved distribution parameter validation
o Enhanced data export – see next item.
Data import/export – new functionality makes it easier to work with enterprise data sources, statistics, visualization and business intelligence packages
o Vensim can now import and export two new data types, relational and tidy. See: VDF2DLIST, VDF2TIDY, DLIST2VDF, TIDY2VDF
o Sensitivity simulation export has been greatly enhanced, and also includes tidy and relational formats – see SENS2FILE
The Runs Compare tool can now be used with non-simulation sources (i.e. .vdf files from data)
Many bug fixes on the Mac.