Traditionally, expert engineering testimony is given orally, sometimes with the assistance of charts, drawings, and photographs. Often, however, these forms of evidence cannot adequately convey an expert's opinion of the physical facts, particularly when complex interactions or subtleties of timing are involved. Computer animation provides an effective way to demonstrate these events. Computer animation is not without its own problems.
Judges are rightly cautious of the powerful and potentially prejudicial effect of animation.
The animation must be an accurate and complete representation of the expert's analysis and opinion. Judges must be convinced that the complexities of the events in question require animation to accurately communicate an expert opinion to the court. If the animation is accurate and appropriate, admissibility becomes largely a mechanical process. It is not, however, guaranteed. Opposing counsel must be told about the animation as early as possible, and responses prepared for any objections to its admissibility.