RangeModel (2004-2012) was an animated, graphical, freeware application designed to demonstrate the mechanism behind the mid-domain effect (MDE), with tools for exploring the effects of both theoretical and empirical range size frequency distributions (RSFDs) for one-dimensional domains and statistical tools to evaluate the contribution of MDE to empirical patterns. Unfortunately, RangeModel no longer runs under current operating systems. The User's Guide is posted here for historical purposes.

Fortunately, thanks to Aniruddha Marathe,  an R version is available from GitHub, with key elements of the original RangeModel, and new tools as well.

Range Model User' Guide (historical). RangeModel: The Mid-Domain Effect Users Guide.pdf

Software Notes article on RangeModel in Ecography: Colwell 08 ECOGR RangeModel.pdf