(a) Event Sequence Reconstruction, a.k.a. Telling a Story: the computer
is an artist's easel; a series of still images are shown in quick succession, thereby
creating artificial motion or the passing of time. The objects (people, cars, buildings,
landscaping) used may be drawn to scale, have great detail, or be just bare outer shells.
Some critics have called them hi-tech cartoons. Others use them as demonstrative
evidence or to supplement opening arguments, and closing statements.
This type of animation is commonly used to: re-create events; summarize or illustrate
the testimony of a lay witness or an expert's opinion; give the jury a "view" of
places that have changed; or simplify complex technical processes.
(b) Simulations a.k.a. Actual Re-enactments: the forensic expert/engineer uses a
specially written software to "re-create" an event or simulate reality inside a
computer. The resulting animated re-enactment or diagram is a representation of the
calculations (speed and weight of the car, road conditions, etc.) that have taken place
inside the computer.
Simulations have been used as demonstrative evidence to help fact finders understand
the Expert's findings, or help form the basis of expert testimony.