Hugh Borbidge, BSME, Director of Engineering Animations ::::
There are many ways to re-create vehicle movement in a 3D computer environment. Some methods are better than others. We will talk about 3 different methods; simple, rigged, and physics based.
The simple method is the easiest and fastest method as the name implies. The vehicle is treated as one object. The chassis and wheels do not move independent of each other. They all move as a unit. In the image above, the red lines represent the tire paths. You can see that the front and rear tires follow the same path even as the vehicle makes a turn. This is not scientifically accurate but can sometimes be useful for a “down and dirty” review for things like basic spatial relationships.
In some cases the rigged method allows us to separate the chassis and wheels to allow for scientifically accurate turns, one that abides by the applicable laws of physics. In the image above, the red lines accurately demonstrate the paths of the front tires while the blue lines demonstrate the paths of the rear tires. As you can see, the blue lines track to the inside of the red lines. This is called “off-tracking”.
The physics based method utilizes a physics based simulation program to define vehicle movement. The vehicle turn is scientifically accurate as is the rigged turn but the physics based method allows us to accurately demonstrate post impact movement based on the laws of physics (i.e. conservation of momentum). See the image above.
All three methods can be useful depending on your specific demonstrative needs.
For additional information on DJS Associates’ Accurate, To-Scale Three-Dimensional Demonstrative Exhibits, please contact Hugh B. Borbidge, BSME, Director of Engineering Animations at experts@forensicDJS.com or by phone at 215-659-2010.