Realistic motion simulation lets you test your designs in a virtual environment.
Michael Swaine
Rating: Very Good/Outstanding (4.5 of 5 mice)
WORKING MODEL APPLIES the laws of physics to computer-based motion simulation so accurately that it's become a trusted tool in accident reconstruction and product-liability lawsuits as well as in design engineering and analysis. The latest version gives you more flexibility by adding a programming language. This version also has improved speed, ease of use, and compatibility with other programs and file types.
Joint Cooperation
You create the objects for your simulation, such as cars or an engine, by dragging and dropping basic shapes from the tool palette into the main window. Then you connect the shapes with rotating, sliding, or fixed joints, which you also pick from the tool palette. When you click on an object, a Properties window appears, in which you assign physical properties -- such as mass, elasticity, and static friction -- to objects.
Once your objects have real-world properties, you set up your motion simulation. You can give objects their own velocity and trajectory by either drawing velocity vectors or selecting any one of a variety of forces, including directed and twisting forces against or between bodies, from the tool bar. You can set environmental variables such as air resistance and gravity with menu commands. Last of all, you decide how fast you want your simulation to run and how you want to display the variables your simulation calculates. Working Model automatically takes into account your object's properties, the forces you're using, and the environment when it creates a simulation.
Setting up simulations isn't considerably different in Working Model 3.0 than in earlier versions. However, Working Model 3.0 includes Working Model Basic (WM Basic), a complete object-oriented programming language that's similar to Microsoft's Visual Basic. You don't have to use WM Basic in order to create simulations in Working Model, which is fortunate, since the language is difficult to master without previous programming experience.
But if you put in the effort to learn the language, it can be invaluable. You can write a WM program to automate the testing process. For instance, you can run a long series of simulations that test how varying a parameter, such as speed or elasticity, affects the results and then log the results to a file. You can create simulations and build a shell for them, so that a user who's unfamiliar with Working Model can still explore the laws of physics just by clicking in a few dialog boxes or changing a parameter. WM Basic also makes it possible for developers of other programs to create and sell Working Model add-ons to link their products with Working Model. For instance, with such a program, you could assign Working Model physical properties to objects while you designed them in a CAD program.
Information Exchange
Thanks to WM Basic's Apple-events support, other applications can query Working Model for a simulation's results. This means you can also write a complex program that processes data from real-time user input or a spreadsheet and pump the values into a Working Model simulation.
Smart and Smarter
Even without WM Basic, you have more control over your simulations in this version. You can now position or reposition an object by typing in its x and y coordinates in the Properties window.
The Smart Editor keeps objects linked together correctly during the course of a simulation. In Working Model 3.0, the Smart Editor also adjusts the joints and keeps them in their proper place when you resize an object.
Some real productivity-enhancing improvements are the use of point- and geometry-based parametrics. For any object, Working Model allows you to use point-based information, such as position, velocity, and acceleration, and geometry-based information, such as width, height, and centerpoint, in formulas. The ability to use these parametrics tightens up the control you have -- for instance, now you can keep the endpoint of a spring tight against the midpoint of a rectangle as you enlarge the rectangle.
Working Model is now also more consistent with CAD-program standards. This version features a new center-of-mass symbol, and you can snap objects to geometric points such as centers and endpoints.
Working Model 3.0 reads files from Addison-Wesley's Student Edition and any previous Working Model version. You can also save Working Model 3.0 files as Stu-dent Edition or Working Model 2.0 files. However, since geometry-based parametrics don't exist in those versions, the parametrics are converted to numeric constants.
Overall, Working Model 3.0 is faster -- which almost makes up for the lack of a PowerPC-native version. The speed boost is due in part to the faster -- and more accurate -- Kutta-Merson integration technique, which Working Model now uses in calculating simulations.
The Bottom Line
The addition of Working Model Basic adds so much power and functionality to Working Model that it's practically a new product to those who can take advantage of the language. And version 3.0's improved speed and flexibility are added pluses.
Price: $2,495 (list). Company: Knowledge Revolution, San Mateo, CA; 800-766-6615 or 415-574-7777. Reader Service: Circle #412.
Thanks to a new embedded programming language, Working Model lets you link its motion-simulation capabilities to CAD programs, scientific input hardware, and more, so you can streamline your testing process.
