Links to these commercial packages can be found on the Environment page.
Either locate the default directory for user-installed Mathematica packages (e.g., ~/Library/Mathematica/Applications for Mathematica 5.x on Mac OS X) or create a directory specifically for the purposes (e.g., ~/pendtoolkit). Download the master archive from the Toolkit page, and unpack it and all subarchives into the package directory. Each package comes in .nb and .m versions. The .nb file is the source and contains the comments. The .m file is the version actually loaded. It is automatically regenerated whenever the corresponding .nb file is edited. Make sure that all the .nb and .m files are at the top level, moving them out of subdirectories if necessary.
Even if you only want to use one model for the moment, it's a good idea to create a single directory to hold all models created using the toolkit, e.g., ~/pendmodels . Within that, create a directory with a name reflecting the model you want to use, e.g., ~/pendmodels/mbtriple .
Choose a model from the Models page and download it. Unpack it into the directory created in the previous section. This results in ~/pendmodels/mbtriple/current or the like. (The reason for the extra level is that if a new version of the model is ever released you can rename current to old or the like, bring in the new version and then transfer over any cases you've created for the old version.) This directory is called the model directory, and contains the model definition notebook, called ASUS3ModelDefn.nb or the like, plus subdirectories containing the results for different cases.
Each case subdirectory (e.g., default) contains a calculation notebook with a name like ASUS3ModelCalcDefault.nb, and a subdirectory called precomputed with archived intermediate results for that case.
The code that drives the calculation is in the calculation notebooks, and each copy has three hardwired paths that need to be set for the other code to be found: the custom package directory (if the Mathematica default is not used), the model directory, and the case subdirectory for the current case. Therefore, upon downloading and unpacking the model files, repeat the following for each case:
Each model comes with a number of predefined cases, and a good way to start becoming familiar with the software is to load one of them and try the plotting and analysis functions. Look in the case subdirectory and open the calculation notebook. Look for an assignment to useprecomputed at the beginning of the notebook and check that it is set to True.
If you have been working with another model or case, it's a good idea to quit the Mathematica kernel at this point. Select and evaluate from the top of the calculation notebook down through the Preliminaries section. If the paths have been set up correctly, the model definition notebook should be loaded, which in turn should load the toolkit packages. Finally the status window should open. If it doesn't, check for error messages where the path variables are set and used.
Then, select and evaluate some of the sample plots. The calculation has a number of stages. In Stage 0, everything but the wire stiffness is included. Stage 1 adds the wire bending and torsional elasticity. Stage 2 adds the effect of the extra longitudinal extension as wires are bent away from the straight line between the attachment points. Each plotting section begins with a call to Calculate[] (e.g., Calculate[Stage2]) to load or calculate anew the results for a particular stage, followed by some sample plots using the results for that stage. Be sure to evaluate the call to Calculate[] before the associated plots. Since useprecomputed is set to True, you should see messages in the status window indicating that archived results are being read as the Calculate[] call runs. Copy some of the plots and experiment with different parameters.
Take a working case and copy the entire case directory. Give the new directory a name reflecting the purpose of the new case. Rename the calculation notebook in the new directory to match. (The correspondence here doesn't have to be exact - it's just a reminder if you have more than one calculation notebook window open.) Open the notebook, and look for the assignment to modelcase. Change it to match the directory name. (The correspondence here does have to be exact.) Look for the assignment to useprecomputed near the top, and change the right hand side to False.
Then look for the assignment to overrides a bit further down and add, delete or modify substitutions to implement the new case. If you've been working with another model or case, it's a good idea to quit the Mathematica kernel at this point. Finally select and evaluate the entire notebook.