While molecules are generic and will eventually be made for use with all system dynamics software, the current implementation works only with Vensim.
For older Vensim installations, you may install the molecules manually.
The molecules addition requires Vensim (PLE, PLE Plus, Professional, or DSS) version 5 or later.
Getting Ready
Download the molecule installation program if you have not already done so. The Windows version is called molecule.exe, the Macintosh version is called molecule.hqx. If your web browser does not automatically do so, you will need to convert the .hqx file into a Mac executable using a BinHex converter.
Installing—Windows
If Vensim is open close it. From the file manager or explorer, run or double click on molecule.exe. (the .exe portion will not always be visible). Read the copyright and license agreement terms. Click on Accept to accept the terms. A dialog box will appear asking for the directory to install the molecules in. The default directory is C:\VENSIM\MOLECULE. You can choose another drive and directory if you wish. Click on Install and the molecules will be installed.
Installing—Macintosh
If Vensim is open close it. Double click on Molecule Installer. Review the Copyright and license information and click on continue to accept the terms. Choose a folder to install the molecules into and click on Install. It is probably easiest to install the molecules into the folder containing the Vensim program file.
Configuring Vensim to Use Molecules
If the molecule installation program is successful, you can simply use the menu item Windows>Molecule command to open the master molecule. If there is a problem with installation, or if you install Vensim after you install the molecules, you will need to specify the full path to the molecule directory for Vensim. This path takes the form C:\VENSIM\MOLECULE\ on the PC (it is important to keep the last \ in place) and :MacintoshHD:Vensim:Molecule: on the Macintosh (it is important to keep the last : in place).
Vensim PLE/PLE Plus
If Vensim PLE fails to open the molecules from the Windows>Molecule command, you will be prompted to type in the path for the molecule directory.
Vensim Professional and DSS
Under Tools>Options>Startup there is an entry for Molecules. Type the full path name next to this entry. You will need to close and reopen Vensim after doing this.
