Animate Your CAD

One picture is still worth a thousand words. But "one animation is worth a thousand pictures," says Jeffrey Simon, president & CEO of Immersive Design, Inc. (Acton, MA).

Animations tell a story. And, continues Simon, animations can communicate complex designs worldwide while bypassing the linguistic barriers that come from text or speech translations.

Or the not-so-worldwide linguistic barriers between technical and non-technical people. Visit a typical design review meeting, for example. "We would all sit around looking at blueprints or some kind of detailed 2D drawing," muses Richard Tomazin, Engineering manager for DCD Technologies (Cleveland, OH), a designer and manufacturer of medium-sized die-cast molds (typically for 400-ton to 1,200-ton die casting machines). "A lot of people sat around shaking their heads, saying they understood." In reality, they didn't. Animations can change that. "Seeing objects move around, interacting with one another in an assembly or disassembly sequence, puts new light on what you're actually seeing," says Tomazin.

Lately, several software products have been adding a fourth dimension—time—to conventional three-dimensional (3D) solids modeling. The result: Animations that impart far more information than conventional, static computer-aided design (CAD) drawings and 3D models.

Creating Animations

IPA (Interactive Product Animator) from Immersive Design creates interactive, photo-realistic animations of product designs from 3D solid modeling files. Once created, these animations are not dependent on the source CAD package. Nor IPA, for that matter.

This Windows 32-bit application can execute from within a CAD system, similar to a plug-in for Netscape, or as a standalone application. In the former configuration, IPA can be a plug-in within Parametric Technology's Pro/Engineer, SDRC's I-DEAS Master Series, SolidWorks, and Unigraphics Solutions' SolidEdge. IPA becomes just another "menu pick" on a drop-down menu within these CAD systems. When operating IPA as a standalone application, the user can simply "drag and drop" a native CAD file onto the IPA window.

In either configuration, IPA reads CAD file or database for the object or assembly tree, part constraints and attributes (such as color), and tessellated data. Reading this information can take a few minutes for CAD files containing about 500 parts; for larger files containing upwards of 6,000 parts, the process takes about 10 to 15 minutes.

The IPA user interface consists of several windows that show the assembly tree, the model, and an animation time grid. In the assembly tree window, parts and sub-assemblies can be dragged-and-dropped to different locations to change parent-child relationships. This is also the window to set part properties, such as activating or hiding parts, and setting visual parameters.

In the model window, users can dynamically manipulate parts and viewpoints. Following "key framing" techniques, the user identifies a part's location at various moments in time. These locations are recorded as a series of individual time steps. IPA then interpolates the part's path and movement between time steps, creating smooth motion—animation. These recorded movements can be played back for individual parts or complete assemblies. Moreover, the movements can be updated or deleted, and new motions inserted between time steps.

Using the time grid window, the user can then set start times, speeds, and durations, thereby creating complex part movements.

In each of these windows, IPA offers a host of features to manipulate 3D solid model files into animation. For example, IPA provides editable motion paths, definable start and end frames, and the ability to animate the attributes of objects (such as position, color, and transparency), environment (such as background images and color), and light (such as intensity, color, angle, and orientation). Visualization features include 24-bit true color, texturing, detailing, enhanced shadow, true reflection, and anti-aliasing. Users can add text and labels to objects in motion, swap backgrounds and planes to enhance visualization, and continuously change view orientation during animation. And there are Wizards to help out users.

An update feature helps ensure that IPA animations reflect changes made to the source CAD file. Once initiated, this feature opens the modified source CAD file and transfers any new information into the existing IPA animation.

IPA accepts data in a variety of file formats, including 3D solid model files from SolidWorks, Pro/Engineer, I-DEAS, and Solid Edge, as well as stereolithographic (STL), Windows bitmap (BMP), Tagged Image File (TIF), JPEG, PhotoWorks (LWI), and Truevision Targa (TGA). IPA animation outputs include Microsoft Video for Windows (AVI), BMP, JPEG, TIF, and Virtual Reality Modeling Language (VRML) and VRML 2.0.

Two items of interest regarding these file formats. First, the input side. STL has become a common neutral format for generating, albeit limited, faceted design file. Most, if not all, solid modelers can produce STL files. Ergo, IPA can create animations from most, if not all, solid modelers.

Second, the output side. Microsoft AVIs can be viewed on any Windows-compatible computer. Moreover, AVIs can be easily "dragged and dropped" into any Microsoft Word document and PowerPoint presentation, sent by email, posted on web sites, and can include hyperlinks to relevant web sites, applications, or files.

Benefits Go Beyond the Visual

IPA solves a variety of problems associated with CAD data. It lets anybody with a Windows-compatible computer view 3D models—better, 3D animations, namely the AVI files. There is no need for proprietary or native CAD applications. "The animations can be shared over e-mail and the Internet, decreasing the time it takes for the product to move through its lifecycle," says Simon. The model files are small—kilobytes rather than megabytes—so they move from computer to computer without much network overhead.

And the product is easy to use, so engineers and management are more apt to want to use the tool to communicate engineering product design data to people outside of engineering. DCD's Tomazin estimates that a user can be creating animations in two hours—in an afternoon tops—using IPA.

In fact, Tomazin considers IPA to be a "desktop publishing tool to create shared images across an enterprise. It's a tool that lets AVIs float to wherever and to whomever needs to see that visual image." Within DCD, AVI-based training from IPA has halved the training time for a new product or process among shop floor employees. It has also significantly increased their level of understanding and retention.

IPA-generated AVIs also help DCD's design review meetings. These meetings can include engineers, the die makers who are assembling the tools, the operator of the electrical discharge machines, even the scheduling manager who needs to know what components a mold contains.

Case in point: The engineers used IPA animation to explain a new semi-solid process for building new tooling, and in so doing, that one meeting justified the cost of IPA. "Within two hours, everyone had a good idea of how the tool worked. Take the ten people at that meeting and multiply by two hours; that's 20 hours of work. It would probably have taken 20 hours for each individual to sit down and understand the drawings at that meeting."

Outside DCD, the company frequently uses the AVIs as a sales tool, showing end-customers how DCD's finished dies will create the customer's parts.

Animations for Good Measure

There are other Windows-based software applications for creating animations, starting with the CAD vendors themselves. For instance, SolidWorks (Concord, MA) has simple animation capabilities so that users can see how parts and assemblies move. However, these animations can only be viewed using SolidWorks. Moreover, the animations are not particularly fancy; SolidWorks does not generate special affects such as fly-throughs and visuals showing how pieces come together as assemblies. SolidWorks shows simple motions: parts move and the complete assembly model can rotate on the screen.

A more sophisticated approach comes from MSC Working Knowledge (San Mateo, CA), a division of MacNeal-Schwendler Corp., which offers a family of increasingly feature-rich, physics-based engineering software systems that, as Greg Milliken, director of Marketing, puts it, "deal with things across time." Working Model View, for instance, provides viewing, annotation, and markup tools, and can be used to annotate or measure a functioning, moving assembly, or to view the results of simulation tests.

The company's latest product, Working Model Studio, integrates physics-based simulation with traditional photorealistic animation techniques. The resulting animations behave as they would in real life. Gravity, friction, torques, and all those other natural forces that act on mechanical systems, as well as motors and driving actuators, are taken into account.

Another product in the family, Working Model Motion (formerly Working Model 3D), goes beyond Studio by including a variety of "intelligent" objects to represent moving devices, such as conveyor belts and bushings. The Motion product doesn't just simulate how mechanical parts and assemblies will move; it lets users perform kinematic and dynamic analysis by both seeing and measuring what forces are being applied at any point to those parts and assemblies.

Do You Need Sophisticated Animation?

Other software can generate the more complex animations, such as the television commercial that shows how an automobile's engine and car suspension operate under a "transparent" body.

Such sophisticated animations come at a cost, though. For starters, they involve manipulating and then displaying huge data sets. For the nonce, this is still primarily the domain of Unix-based applications, not Windows NT-based computers. Second, generating the animations is often a tedious, intense, time-consuming endeavor. For example, IPA generates animations at 7.5 frames/second; Toy Story needed 30 to 50 frames/second. IPA animations are created in about an hour; at most, 3.5 minutes of animation was produced each week to make Toy Story (least number of minutes required to render a frame of film: 45). "But a lot of the techniques they use, we use," says Simon.

Last, the high-end, Unix-based animation systems are relatively expensive. For example, Engineering Animation, Inc. (EAI, Ames, IA) is a leader in high-end animation systems for engineering applications (versus entertainment). EAI software products sell for $22,000 to $28,000. Immersive's IPA software sells for $2,495 per seat. (Working Model Studio, available in April 1999, is expected to cost about the same.)

At issue is how much simulation—how much like real life—does an animation really need to show your boss or your customer? Not everyone needs the photorealism of human bodies falling off boat decks as in the movie Titanic. Milliken believes that a lot of animation for engineering won't even be photorealistic. "It'll just be smooth-shaded and things may go transparent so you can see the internal workings of a motor or something," he says.

The jury is still out on that. What is known is that animations of 3D part and assembly designs are here to stay. "Right now it's still in the pioneering stage," says Joe Dunne, Gold Partner Product Manager for SolidWorks. "People are just now realizing they like photorealistic renderings. Adding motion is a natural progression."