Working Model 2D Version 4.0.1 combines improved speed, new built-in features, Working Model Basic utilities, and user-interface enhancements to increase the overall productivity of this versatile simulation software.

Version 4, now a 32-bit application, is about twice as fast as Version 3 on the same platform. I compared the speed of Versions 3 and 4 for a variety of simulation models. For reference, I ran Version 3 on two platforms: a 486, 66 with Windows for Workgroups 3.11; and a Pentium 133 with Windows NT 3.51. Version 3 ran 3.5 to 5 times faster on the Pentium than on the slower 486, demonstrating the value of using the most powerful PC available. The new release, Version 4, solved the same models 1.6 to 2.5 times faster than Version 3 on the Pentium/NT platform, a speed improvement apparently due to the change to a 32-bit application. Knowledge Revolution reports speed improvements as great as 8 to 1 for some models.

Version 4 expands the set of body primitives to include NURBS-based curved bodies. Curved bodies are fully supported by collision detection, providing a basis for modeling the interactions of cams and followers as well as a wide variety of other curved machine elements and free bodies. This is an important addition, providing exceptionally flexible modeling of body interactions. Curved body solutions run rapidly. I found them practical for a variety of applications.

Curved body control coordinates can be imported and exported via the clipboard; however, output interpolation, which is offered for curved-slot output, isn't available for curved bodies. This would be a useful addition to increase the accuracy of geometry output to other applications.

Version 4.0.1 adds several WM Basic script files that provide useful functions and excellent examples of the capability of WM Basic as a construction tool. The first, pin friction, adds a motor at a previously defined pinned joint. The utility adds controls which vary effective pin radius and bearing coefficient of friction. The motor generates a torque which models bearing friction as a function of the pin joint constraint force. I've created similar joints myself, and welcome this automatic feature. It saves time and reduces the potential for error in entering the functional description of the friction torque.

The second script file creates a simple, finite-element model of a constant-section, flexible beam. Given a rectangle which defines the beam's height and length, the utility divides the rectangle into evenly spaced sub-rectangles which are joined by pin joints with rotational springs at the joints. Parameters include the number of beam elements and the beam's EI. Discretion is needed when modeling stiff components, since the meshed models can include multiple, high-frequency modes which are computationally intensive. Flexible elements should be used sparingly; but when appropriate, the script utility creates them easily. Adding a nice touch, another script file automatically returns these meshed models back to their original form.

In addition to the printed tutorial, Version 4 adds Workshop Projects to the Help database. These are step-by-step tutorials that can be viewed beside an active Working Model project. This approach offers the potential to include a very large database of example problems; however, screen limitations make it difficult to retain the needed illustrations with the associated text. Improvement in presentation is needed to make this training aid preferable to the printed lessons.

The user interface now includes dockable tool palettes, offering flexibility in workspace organization. This full complement of tools eliminates the need to use pop-up palettes, making it easier for beginners to find tools, and faster for experienced users.

Version 4 is a significant improvement. The speed increase and addition of curved bodies, alone, make the upgrade worthwhile.

Spec box: Working Model 2D Version 4.0.1

Working Model is a dynamics simulation tool with easy-to-use, pictorial input and powerful output-data presentation capabilities. It includes a powerful collision solver, making it easy to model complex machine element interactions. A Pentium with at least 16 MBytes of RAM is recommended. This is a 32-bit application and requires Windows NT 3.51 or higher, or Windows 95. Version 4 uses a Hardware Key for security.

List Price: $3,500

Knowledge Revolution, 66 Bovet Rd., Suite 200, San Mateo, CA 94402; ph: (415) 574-7777; http://www.krev.com

A similar product: Analytix -- Saltire Software, Box 1565, Beaverton, OR 97075.