Forensic Animation in MapScenes PRO | Back to User Tips

Reprinted from ARC Network Newsletter, 2003

Traffic collisions are very complex events that occur in a very short duration of time. A problem facing crash reconstructionists is trying to relay the results of their analysis to the Court in a manner that is fully comprehended. As a crash reconstructionist, hours of expert witness testimony is often needed in order to explain the results to the jury. In addition, testimony may have to be supplemented by illustrations or exhibits. Some examples of these exhibits may include the pre- and post-impact movements of vehicles, view obstructions, and many other things that may or may not have been factors in a crash.

Forensic animation is an extremely powerful tool for doing this. It illustrates the expert opinion in a very short duration of time (usually a few minutes). The animation also presents it in a manner that all jurors can understand. After the jury views an animation, there is an increased chance the individual jurors will have a uniform view of what idea the expert witness is trying to convey. Furthermore, there have been numerous studies showing that jurors have a much higher retention level when information is presented visually instead of verbally.

A demonstrative animation is a series of scale diagrams shown at a specified rate (usually 30 frames per second or 30 fps). This is analogous to children’s books that have a sketch in the corner of the pages. When one flips through the pages quickly, it gives the illusion the sketch has movement. When playing animations at a rate of 30 fps, the human eye cannot detect the transition from frame-to-frame and creates the illusion of motion.

As with any demonstrative evidence, the animation must be a fair and accurate representation of the crash scene in order to be admitted into court as evidence. Photographs, scale diagrams, and even witness statements can support the accuracy of the animations. It must not be prejudicial or be too dramatic. It should not show graphic effects such as blood, body injuries, facial expressions, and so forth, because it may excessively persuade the jury. Individual judges control the admissibility of evidence into the courtroom. Given the effectiveness of forensic animations, attorneys will undoubtedly do everything they can to suppress this type of evidence.

The animation feature in MapScenes Pro is a welcome addition, once again raising the bar for the other popular programs available. This inclusive package is so nice to work with. No other modules or add-ons. Everything that is needed is on one cd.

The surprise here is not in the complexity of the program. Creating a two-dimensional or three-dimensional animation is very easy while maintaining data integrity. Maintaining the data integrity is of critical importance because this is a common point of scrutiny when challenged by opposing counsel.

Before beginning the creation of the animation, some planning is involved. The measured locations at impact and rest, orientations, speeds, and accelerations of the objects being animated must be determined. The “objects” in this case are mostly motor vehicles such as cars, trucks, and motorcycles.

MapScenes PRO provides the flexibility of two different methods of constructing an animation. It utilizes two methods of generating frames between the keyframes. In animation, a keyframe is a frame that marks the position of an object at a point in time. A series of keyframes show the object at key positions during the course of motion. The first method is a simple linear interpolation between keyframes, or in-betweening. In-betweening is the process of adding frames between keyframes to produce smooth motion. This is based on the time difference between the two keyframes. This interpolation determines the position of each object for each of the in-between frames. The second method defines the speed, acceleration, and direction of movement of an object at a keyframe. The location of each object for the in-between frames is calculated based on the speed, acceleration and direction of movement for that object. The kinematics equations in the Scene Analysis menu can be used to aid in the calculation of the object’s positions and orientations required to create accurate keyframes.

When all the attributes of the various objects within the animation are defined, MapScenes PRO can create a preview. During this preview stage, the user has full control to evaluate the animation. Once the user is satisfied with the results, they can create a movie of the animation that can be viewed on any computer. This is effective in communicating with the jury. The end result is the ultimate method to relay highly technical information to the jury in a manner that individual jurors can understand and retain.

MapScenes Pro is tried and tested technology that meets the needs of today’s reconstructionists while respecting the logical input of data and time management. Whether complex or simple, MapScenes PRO is able to take the data directly from the total station and produce highly detailed diagrams of the scene. Land contours and roadway profiles can be seamlessly created. The software also has a new Symbol Librarian for inserting specialized symbols into a drawing. With over 7,000 two- and three-dimensional symbols, the user usually finds the symbol that is needed. If not, creating one is a simple process.

The Scene Analysis feature is unique when compared to other CAD programs. It allows me to calculate vehicle speeds using the conservation of linear momentum, kinetic energy, and other methods of speed determination. I can also calculate time and distance values using the numerous kinematics equations listed for this feature. All of these things help the reconstructionist plan out their animation.

This affordable, well-rounded package offers me the tools needed to reconstruct a crash and prepare for Court with confidence. Combining the knowledge of the reconstructionist along the innovative features of MapScenes Pro produces professional results that are simply unmatched by the competition.

By Gregory Gravesen
Greg is an A.C.T.A.R. Accredited Accident Reconstructionist and state law enforcement officer. Greg is also a partner in Collision Analysis and Reconstruction Services, providing collision reconstruction services and expert witness testimony since 1987.