Software Lab 6-8-98

June 8, 1998 Design News

SOFTWARE LAB Reviews on tools of the trade

3D Studio MAX R2

Hunter Davidson, Jr. Mechanical Engineer Northrop Grumman ESSD, Oceanic Systems

MAX R2 offers a dazzling range of enhancements for media production, including modeling, special effects, lighting, materials, rendering, and Video Post features. Since I'm not an artist or media expert, I'll forego comments in most of these areas and stick to my primary area of interest--analysis and visualization of mechanical designs during the conceptual design process.

For my MAX applications, R2's new scripting language, MAXScript, is the single most significant addition. MAXScript provides welcome connections to other engineering applications, and provides valuable tools for control and productivity within MAX.

MAXScript is an object-oriented, full-featured programming language providing access to nearly every MAX command and process available through the normal user interface as well as general file I/O.

In my first application of MAXScript, I created a custom rollout with spinner controls of the mechanical joints of a nine-joint handling mechanism. This provided much simpler and quicker interaction with the model than is possible with the standard user interface, and permitted very efficient exploration of component paths for controller concept development. Critical joint position combinations could be recorded as animation keys, speeding the process of animation development. Since the custom controllers are applicable to forward or inverse kinematics, and can control follow objects as well, the technique is useful for all kinematic options.

Next, I generated a kinematic model in Working Model and exported key joint positions and loads to an ASCII file. I then created a kinematically identical (though geometrically more realistic) model in MAX R2, and wrote a script that read the ASCII file data and recorded the joint positions as animation keys. The R2 model followed the kinematically correct motions, with realistic visualization of the mechanism.

For fun, I added code that mapped the joint loads to component color, providing a rough analog to a FEA model's color contours. Highly loaded components turned red, with cooler colors indicating low loads--with new data automatically transferred from the external application.

This suggests endless possibilities for visualizing design behavior, and could be extended to include animated, 3D "graphs" of any kind of data. Note that all model parameters can be controlled with scripts.

MAX R2 adds a new IK mode using automatically linking bones, providing quickly generated, efficient and accurate, fully interactive kinematic models. I constructed a few simple linkage models, and found the new tool effective. R2 also adds dynamic simulation tools that include inertial reactions to loads, and flexible tools for collision detection. Combined with the ability to import data from dedicated simulation software, and to export solutions for other analysis, MAX is now a powerful mechanical analysis and visualization tool.

I was pleased to find surface following capabilities, both with the new Attachment and Surface Controllers, as well as with scripts. Typical uses include vehicles following terrain. On the rendering front, the addition of global lighting control is a great timesaver for scenes involving many lights.

While I'm very pleased with the results from scripting and other new features, the learning process, particularly for scripting, was more difficult than I'd hoped. The printed tutorial and user's manuals leave many new features insufficiently documented, and the online documentation best serves those who already know what they're looking for. I stumbled on a sample script called "demo.ms," which is one of the best executed, interactive tutorials I've ever seen. I also used the excellent New Riders book, Inside 3D Studio MAX 2, as a supplement. I think that MAX's broad usefulness warrants some more basic instructional material. Not all of us are experts in rotational geometry and object-oriented programming.

That aside, I'm ecstatic about MAX's new features, and believe it's found a home on mechanical engineer's PCs.