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Autodesk Inventor : PacWest Racing Group

In the fast-paced world of professional car racing, the creation of new cars within very short design cycles can be the harder race to win. The PacWest Racing Group is realizing the benefits of using Autodesk Inventor software, which is helping the company turn new designs around more quickly than ever before.

PacWest Racing Group has competed in CART auto racing since Bruce R. McCaw formed the team in 1993. Julian Karras is PacWest's drawing office manager who oversees product design, detail, and development, as well as all enhancement projects related to the company's race cars.

CAD/CAM/CAE technology helps win races
PacWest works closely with Reynard, its chassis supplier. Reynard uses another CAD system to work on PacWest's new car designs. The two companies must be able to collaborate effectively with one another regarding the design of the car. "Gone are the days of drawing boards and pencils. Now information is exchanged electronically. The use of quality CAD systems is a necessity rather than a luxury," notes Karras.

The CART racing season begins each February and ends in October. That means the window to design, analyze, and test a new car is just three months. In fact, next year's PacWest car designs are being completed right now. "Reynard will begin manufacturing soon and deliver the first car to us for next year's season by November 2000," said Karras. There are 22 races scheduled around the world for 2001.

"Between now and mid February," said Karras, "Reynard and PacWest collaborate to design, analyze, and tweak two cars to be ready for the first race. Next year, the new racing rules disallow all race teams from any in-season testing - no on-track testing. The only methods to test a car will be to do it off-season or virtually using simulation software."

Karras and his team rely on 2D and 3D design information. The design department uses a variety of CAD tools including AutoCAD, Mechanical Desktop software, and Autodesk Inventor software. "We still use AutoCAD because a lot of our drawings from Reynard come to us in 2D format. As far as Autodesk Inventor is concerned, I use the software a lot and I haven't had a single hour's worth of training since installing it just three months ago," says Karras. "I taught myself how to use it. I just started using it, followed the prompts, and made common sense decisions on what I needed to do.

"The software follows along with you-coaching you along as you go. Only certain icons are available to you once you get to a certain stage in a project. The software is very intelligent. It knows where you are at all stages of a particular project and actively guides you along the way-without getting in your way. The technology analyzes whether you are providing good or bad information as well. It's part of the advanced Adaptive Technology that Inventor is based on. The overall interface is more user friendly than Mechanical Desktop or any other type of CAD software I have ever used."

Autodesk Inventor as a design assistant
As recently as last week, Karras was using Autodesk Inventor to design a drive shaft assembly-the output flanges that come out of the gearbox. Each flange has three precision pockets that drive the tripod-like CV joint. Karras says, "I sketched the profile on the front face. However, I sketched it incorrectly because I didn't remove enough material to make it a pocket. Going back to edit that feature was so simple. Inventor knew that I wanted to break out of the pocket into the main diameter of the middle. When I selected that area to add to the extrusion, the software did it for me. It almost knows before you do what you really want to do. Inventor is a huge leap from Mechanical Desktop and the other competitors' programs on the market today."

Karras hope to implement Autodesk Inventor across the board in his design department by the end of 2000. He says that Inventor's simplicity, ease of use, ease of learning, intelligence, and on-screen animations are just a few of the many benefits that he wants everyone involved in new vehicle design to take advantage of.

"One of the greatest benefits of using Inventor," says Karras, "is the on screen animation functionality with constraint driven AVIs. This allows assemblies to operate on screen as they would in real life." He says that proving out mechanical actions on the screen is a huge benefit to check for performance and part compatibility as well as provide assembly instructions for mechanics. Instead of spending a lot of time and effort cranking out a long memo and assembly drawings on how to put together a new assembly or system, Inventor provides the capability to generate a simple AVI to watch over and over on assembly instructions.

In addition, Autodesk Inventor is widely compatible with a range of other software such as FEA and CAM packages. "In the old days," notes Karras, "we faced designing a product, building it, then breaking it because we didn't have the technology or access to the technology to perform FEA or CAM within the CAD application. Inventor makes it easy. We are able to obtain some really accurate results using on-screen simulations."

Moreover, being able to roll the models into FEA allows PacWest to trim excess weight off the vehicle, a critical element when fractions of a second mean winning or losing a race. Then, Karras re-runs FEA situations on the revised part to understand if the vehicle will perform as well or better as a result of the reduced weight even if he reduces weight by tiny amounts on various parts throughout any one vehicle.

"Removing one-fourth of a pound can mean a win or a loss," says, Karras. "Quite substantial gains can be made by saving weight. Shaving 10 pounds is worth one/tenth of a second around an average road coarse. That amount of lead would cover the top five spots in any qualifying grid. So you can imagine the gains that we can potentially make in terms of using the software to reduce weight."

The extensive on-screen design, analyzing, and testing helps save PacWest significant time and money. Karras and his team are also able to very quickly investigate many iterations of alternative designs.

Autodesk Inventor's Sketch Doctor and diagnostics are also exceptional. "Using other CAD software," says Karras, "I could try to blend a fillet into two converging lines that end up being a single point in space. Many times, I would receive an error message that said the ACIS model failed. This caused me to spend time trying to find out what was wrong. Whereas using Inventor, the software notifies the user regarding what is wrong and offers to fix it! Truly, using Inventor, I don't feel as though I am on my own anymore. The software reduces a significant margin for error as it coaches users down the road to the end product much, much faster. Given our design cycle time, that's exactly what we need."

As Autodesk adds surfacing and mold making capabilities to Inventor, Karras believes there is great potential in terms of reducing the amount of physical wind tunnel testing for aerodynamic studies. "Currently, PacWest spends between 30-40 days in the wind tunnel each year. Using Inventor we think we can reduce that time and the costs associated with it."

Karras believes that Autodesk Inventor has huge potential for beyond the design and engineering department and beyond PacWest's four walls. "I predict that sometime in the future Inventor will be used to help graphic designers develop paint scheme for the cars," notes Karras. "The technology will help us obtain a much more virtual understanding of what the paint scheme would look like from different angles. The software will help us, graphics designers, advertising agencies, and our sponsors (Motorola and NexTel) determine what color schemes to use for each car. We will all be able to visualize how the cars will look from different television angles, too."

What learning curve? Learn as you go with Autodesk Inventor.
Since starting to use Autodesk Inventor just three months ago, Karras is hooked. There is no intimidation moving from 2D to Inventor. "I don't think any other 3D product supplier can tout such an easy transition path," notes Karras. He was up and running in an afternoon. In addition, the hardware to drive Autodesk Inventor is not as demanding as some of the other programs. "While it might be nice to have a high-end tool like CATIA," adds Karras. "However, it takes a $40,000 hardware system to run it. That kind of investment is a little hard to justify in most organizations today."

Karras believes that the virtual engineer is just on the racing horizon-someone who designs, analyzes, tests, and proves his design on a virtual on-screen race track. "It used to be that race teams arrived at the track only to find that their design didn't work," adds Karras. "Using all the technology tools that we have today, including Autodesk Inventor, we arrive at the track with a lot more confidence that the car will work the way we believe it will work. With Inventor's help, I am nearly certain that the design will work because I've already run the car through a number of situations before we go to the track."

Author: Laura Carrabine

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Page last modified on September 30, 2000
Copyright 2000 by John Stark