Animation and Scale Drawings
By: Jack Murray, Jr., CLI

It used to be that any animation we did had to be done by an outside studio and usually the cost made it prohibitive for all but the biggest cases. Now, there are several packages available that give you the capability of doing your own animated reconstruction presentations.

Vehicle Dynamics International, 2600 Forum Blvd., Suite C, Columbia, Missouri, 65203-5431 has a software package (LVDS), developed to investigate the complex dynamic responses of light vehicles in a variety of maneuvers including skidding, spinning, and rollover. LVDS utilizes state of the art techniques inmodeling tire behavior, tire roadways interaction, suspension effects, steering control systems and vehicle dynamics. A3-D non-linear vehicle model of intermediate detail is generated according to used specifications, and properly accounts for vehicle forward, lateral, vertical, roll and directional dynamics. The program is menu driven and fully interactive and allows the user to reconstruct and investigate any vehicle motion.

The LVAS Software package , is a package of micro computer programs developed to provide state of the art accident animations utilizing data obtained from LVDS or other simulation programs. Any three dimensional vehicle motion can be animated and played back in real time, in slow motion, or frame by frame, on color and monochrome monitors. LVAS software programs enable the user to quickly assess and analyze the overall response of all types of light vehicles in critical accident situations. This is particularly useful in visualizing the time history of response variable for a given vehicle, quickly and reliably.

Engineering Dynamics Corporation, 8625 SW Cascade Boulevard, Suite 200, Beaverton, OR 97005, has a package of five vehicle dynamics programs, called EDVAP.

While each program is suited to a particular need, all the programs have the same menu structure. The user responds to a series of questions regarding the vehicles and accident site. The results are then displayed in a format requested by the user. Some of the capabilities include high resolution, color accident site drawings and vehicle/occupant motion. Intercommunication of data between programs allows merging of results from input, output, and graphics, automatic loading of typical vehicle and occupancy information and on-line help prompts.

Scale Drawings
Many of us have been doing scale drawings for years without any kind of computer aide, but like everything else, this area is now so much easier and more efficient with the use of computers you are almost forced into their use.

I was never very good at college drafting courses, but with a set of K & E pens, scribes, lettering templates, etc., I survived. Depending on the amount of detail that was necessary, a considerable amount of time would be spent laying out streets, noting final resting place of vehicles, making sure you got the correct scale and everything "fit." The original would be in pencil and then you had to go back over it in ink. One little slip, and you had a real time problem on your hands. Clients don't pay for your carelessness.

With any number of CAD programs on the market, you can take your same measurements, do a rough field sketch, take a good set of photos and then go back and put together a professional quality diagram in about a third of the time it used to take and it's generally a lot more accurate. Here, more than anywhere else, the finished product is a reflection of your accuracy in developing the input. Never has the "garbage in, garbage out," theory been more prevalent.

At present we do our measurements, shoot the film, and take our field work to a professional engineering firm that produces court size scales, as well as extra 8 x 10s for depositions, interviews with witnesses, etc. This is cheaper for us and saves a lot of time. Ultimately, we will probably be doing our own CAD work, but for the moment, we farm it out. A good suggestion for those of you who do not do a high volume of this kind of work.

The actual measurements at a site are now a lot simpler with the use of laser guns and laptop computers. Laser Technology, Inc., 7399 South Tucson Way, Englewood, CO 80112 has a package called LTI20-20 which is basically a laser gun that you use with your own laptop or home-based computer. The gun is guaranteed to be accurate plus or minus six inches, working on non cooperative targets for easy triangulation. It has a non detectable lazer beam, is lane selective and has computer interface technology available. I have worked with an engineer here in the Dallas area who uses on of these units and they are really neat for very complex intersections, and/or cloverleafs. They can save you an unbelievable amount of time and their accuracy is superb. The only problem is the cost: about $8,000 plus the laptop. Here again, budget is a serious consideration. We just don't do enough drawings requiring this kind of usage to justify owning one. It is much simpler and economically more feasible to subcontract the work.

Everything we have discussed here is geared to IBM compatibles as that is the format with which I am most familiar. I know there are programs out there for MacIntosh, like Collision Calculator produced by Joe Coyle & Associates, 5694 Mission Center Road, Suite 328, San Diego, CA 92168. This package advertises as being able to calculate 65 separate equations that instantly calculate all of the things that STARS does and is priced considerably less, under $100.00.

Unfortunately, space limitations prevent my going into more detail about the listed products and we have left out a lot of other really good products in the market place. Plans for our new book call for reviewing more equipment, and in greater detail.

Jack W. Murray, CLI, has been a member of NALI since 1984. He is the author of several books on investigative subjects. Murray may be contacted at: 3942 Rochelle, Dallas, TX 75220. Phone: (214)902-9156.