See Also
Stella will open any XMILE file and most Vensim® (from Ventana Systems, Inc.) .mdl files directly. If the source model had stock and flow diagram information it will be retained. If the source model was missing some of all of this information then the diagrammatic information will be created using the same basic algorithm used to create CLD as described in CLD Generation. Larger models will be broken up into modules to simplify the overall layout.
Select Open from the File Menu and then select Vensim MDL file from the type dropdown. Simply select the model and open it.
The opening of Vensim .mdl files (.vmf and .vpd files will not work) is based on the open source project XMUTIL. If parts of models do not translate correctly please leave a note or pull request for that project. We build each release of Stella from the current source as of the time of the release.
If the original Vensim model contains any GET XLS DATA or related function
To the extent possible, the diagram in the original Vensim model will be retained. Views will be placed into modules. Missing variable will be added to the diagrams, in the modules they are most closely associated with. In some cases, it is necessary to create net flow equations since Vensim does not enforce clear inflow and outflow identification or conservation of flows, so additional variables may be created during translation.
When working with Vensim models it can be very useful to export a run from the Vensim model as a tab delimited file and load it in using the Load External Data dialog box. Be sure to check the "Match unqualified names if possible" checkbox.
You can open data files that are in the format described in Creating Import and Export Files using the open command by selecing csv or txt from the dropdown. When opened the names in the file will be used to create variables, and the file itself will be treated as an imported file as specified in the Import Data dialog box. File can also consist simply of a list of names. This is a convenient way to load in and explore data, or create a number of variables from a text file. The variables will all be given the equation NAN.
The opening of XMILE files should work without difficulty. If models in those files contain features not supported by Stella, there may be some difference in results, or some adjustment may be necessary to make the models run. Again, if diagrammatic information is missing it will be added.