There seems to be many preconceived notions about forensic animations and their overall use in litigation. Many times, lawyers or accident reconstructionists will say that “An animation can show whatever the animator wants” or “Animations are difficult to admit in a court of law”. However, to a forensic animator, this is also like saying, that your accountant can “fix your books”. In reality, it is far from the truth.
Misconception #1 – “An animation can show whatever the animator wants”
Perhaps it is the fact that so much of what we see on television and in films is altered with lifelike special effects that we tend to associate anything with 3D visualization with more than a hint of skepticism. Ironically, much of the same software used to animate films such as “Spiderman” or “Lord of the rings” is also less known to be used in scientific visualization, research and forensic animations. People may associate the fact that an experienced special effects animator is capable of creating surreal, yet realistic looking effects. Therefore, it must not be accurate.
The greatest difference between a forensic animation and just any other type of animation is the “forensic” part. This implies that there is a large effort in understanding the details of what is being animated and that there is a large emphasis ensuring a high level of accuracy. An animator can spend more than 70% of his time on activities related to the verification of data and ensuring accuracy in the animation.
An experienced and qualified forensic animator would tell you that a large effort goes into building and checking each step of the animation process to the correct and accurate dimensions. In fact, very little is left to the imagination since most recreations are based on accurate data typically provided by the expert witness. A simple example is the terrain data of a particular scene. This can be obtained by means of a total station along with the positions of important features such as signs, traffic lights, debris or tire marks on the roadway.
Even the animation and motion of objects in a 3D recreation is typically based on information or data provided by the expert witness. This data is often obtained through careful calculations or through the use of simulation software. In the case of simulation software, the data can be directly converted or imported directly into the 3D animation software, leaving little room for error.
There may be cases where the forensic animator is provided with less than ideal information, however, even in these rare instances, an experienced forensic animator will have enough knowledge to ensure that the basic rules of geometry and physics (i.e. motion) are applied and adhered to.
Misconception #2 – “Animations are difficult to admit in a court of law”
Somewhere along the way, there have been animations which were so poorly constructed or erroneous they simply could not have been allowed in court. It would seem that these cases tend to stick in the minds of litigators and cause reluctance for future use of what is a perfectly acceptable and effective use of technology.
Normally, it is an inexperienced animator or lawyer which does not follow some of the basic rules of demonstrative evidence.
Some key points to consider when considering a forensic animation are:
1. The animation needs to support the testimony of the expert witness and should be considered an extension of the witness’ report. The expert witness should be directly involved in authenticating and reviewing the animation.
2. Disclose the animation well in advance of the trial date. Evidence needs to be disclosed in a timely manner and the opponent requires time to cross examine the evidence.
3. The animation fairly and accurately conveys the data or matter that it purports to convey or depict. The animation should not be prejudicial in that it outweighs the probative value.
4. The animation should be relevant.
5. The forensic animator should be prepared to testify that the works created are based on sound technology, process and algorithms such that the final works are a reflection of the expert witness’ opinion.
There are, of course, many other factors to consider which may be case dependent. Further materials and references are available for review including a paper entitled “The Admissibility of Demonstrative Evidence in Jury Trials:” Written by Barbara Legate of Legate and Associates and available at the AI2 forums (www.ai2-3d.com/Forums).
Today, most forensic animations are admitted into court since there are greater considerations and groundwork taken into account to ensure the accuracy, validity and quality of the animations. By choosing an experienced forensic animator and by adhering to the rules of demonstrative evidence, the risks associated with inadmissibility are greatly reduced.
Misconception #3 – “Animation and Simulation are the same thing”
There are two distinct ways to develop an animation and although the end result may try to achieve the same thing, they are fundamentally different in the means by which they are created.
A simulation is typically the output of a program which is operated by a qualified accident reconstructionist. The program has a set of key behaviours (i.e. mathematical equations) which define the movement of objects when given a set of known parameters. It is up to the accident reconstructionist to define all the input variables and ensure they are accurate. Once this is complete, the program is initiated to calculate all the positions of objects through some specific time.
The simulation software may also output the motion of objects in the form of exportable tabularized data and/or animation. However, most manufacturers of simulation based software programs have not been able to achieve the same level of realism as most animators are able to do with 3D visualization software. There may be a number of reasons to this which deal with further complicating already complex software or that perhaps the time spent on development is in the mathematics behind the simulation software and not primarily in the visualization or presentation of the data.
Another important issue which is common with simulation software is the validity of the data available. The old saying “garbage in, garbage out” is applicable. Since a simulation would typically be used as substantive evidence, it can get difficult to prove something is accurate without having solid data to back the animation up.
Demonstrative Evidence – illustrates how something works or how something happened based on the testimony of the expert or eye witness. The animator, not the software is responsible for accurately moving and positioning objects over time.
Does not try to prove anything, but just facilitates the account or testimony of a witness.
Substantive Evidence – Takes actual dynamics and physics into account. The objects are not animated by “hand”, but by software based on calculated inputs or data.
Tries to prove that something may have occurred a certain way.
Visually, an animation is more eye catching and realistic.
Simulations are improving in their presentation, but are still lacking realism.
On the other hand, an animation may be based on an eye witness testimony, calculations of the accident reconstructionist or from data output by a simulation package. All the events of an animation in a typical 3D visualization package are calculated and setup by the animator. Animations are almost always disclosed as demonstrative evidence and they do not try to “prove” anything. They are merely another form of expressing the opinion of the expert witness and are always presented as demonstrative evidence.
Misconception #4 – “We need it yesterday”.
There have been many advances in the technology that forensic animators use which has improved the speed and efficiency of their work. Computer processing speeds have grown exponentially and the advances in software have allowed animators to do things which were simply not possible several years ago. There are even tools provided to animators which allow them to write custom scripts for repetitive tasks and specialized functions.
These advances in speed and ability would make one think that the time to complete an animation should also have been greatly reduced; however, this is not the case.
Part of this reason is simply the nature of the animation process. Much work needs to go into the understanding of the case, reading reports, taking measurements and verifying accuracy. This part alone can take a large part of the man-hours to create the animation.
Also, creating the 3D models (“scene assets”) necessary to populate the animation is still a time consuming process. There are some advantages when a “library” of standard models is used (i.e. stop signs, light poles, traffic signs), however since each case is different and the specific details need to be reflected in the animation (such as the scene topography or specific damage to the vehicle), time must be spent to customize or create models from scratch.