3D Printing – A New Dimension of Expert Testimony


3d Printing and Expert WitnessesWhile some of the techniques used on criminal dramas like CSI may seem like science fiction, recent advances in 3d printing have made the technology increasingly accessible to litigators and forensic experts alike. As a result, 3D printing is shaking things up in the courtroom and the presentation of expert testimonies. With the presentation of 3D replicas in the context of litigation on the rise, we compiled some advice for attorneys interested in leveraging this exciting technology in their own practice.

What is 3D Printing?

Three-dimensional printing is a technique by which 3D scale models can be created to stunning accuracy by a printing machine, using information captured by digital photographs and measurements. Examples of these digitizing systems include laser scanners, light scanners, and photogrammetry. The equipment has become significantly more accessible (and more affordable) over the past few years, allowing the technique to proliferate and find uses in a variety of industries.

Digital images of virtually any real life object, from an entire landscape, to a part of the human body, to the tiniest components of machinery, are uploaded to a 3D printer, which then takes the digitized images and replicates it using one of a variety of materials, such as plastic, metal or ceramic. The entire object is then put together by stacking thin layers of material (much like in the game of Jenga,) and the results are extremely accurate representations of the real thing – essentially a clone. 3D printing is not limited by the size of an object, as it can be used to miniaturize or magnify whatever it may be printing with perfect fidelity.

How Can This Help an Expert in Court?

Attorneys have begun to combine 3D printing with their experts even before litigation ensues. In many instances, using this kind of technology with an expert can help tighten up the central claim, and even reveal the weaknesses or frivolity of a claim. Once in litigation, the use of 3D printing can be extremely helpful where expert witness testimony is concerned. Expert witnesses often face the challenge of presenting to the jury highly scientific subject matter that can be very difficult to understand, let alone visualize. Three-dimensional printing allows for a juror to actually see or even hold  a piece of evidence, which can have an extremely powerful impact on their understanding of an expert’s testimony and ultimately on the outcome of the case.

Examples of use


Medical Malpractice

3D Printing Expert WitnessWhen an expert witness testifies in a medical malpractice case, he or she is often explaining a science-intensive fact that is verbally complicated and difficult to visualize. The use of 3D printing in this context can help jurors quickly understand the expert’s testimony with the benefit of a visual, even tactile, aid. For example, when explaining why an artificial heart valve surgery was negligently performed, an expert first has to explain the relevant structures of the human heart and its place in the cardiovascular system. Now, with the use of the 3D printing, a juror can personally observe and even hold an exact replica of the client’s heart, bringing the substance of the expert’s testimony to life.

Using information from images captured by digital CT scans, 3D printers can replicate details down to the smallest nooks, crannies and crevices that may be present in tissue or bone. These extraordinary details offer clear insights that could not otherwise be observed without invasive procedures. Actual-size replicas of human organs can be created, revealing muscle and tissue irregularities, allowing an expert to explain that a physician was not negligent and that the injury was a result of a condition unique to the client. Even better, since 3D replicas are printed in “layers”, any replica can be split to show cross-sections. In a recent article on 3ders.org, Josh Weinberger, CEO of 3D Printed Evidence, notes that “you can take an x-ray or a medical scan and print out something that is an exact replica of your client’s bone…versus something that kind of replicates it.”

Patent Infringement and Product Liability Cases

3d Printed Expert Witness

One of the most frustrating experiences in a patent infringement case is trying to explain the exact features of the allegedly infringed-upon item to the jury. Charts, graphs, and diagrams are of limited help to the juror when she is asked to picture and comprehend the components of scientific equipment, or the technology inside a new pacemaker on the market. Using 3D models in this context illuminates the expert’s explanation in a way that is not only engaging, but also extremely accurate. In the context of a patent infringement case, 3D replicas are great tools for making comparisons. The expert in such a case can use models of both the original and infringing product to directly demonstrate any material differences or similarities between the two, making his testimony that much more concrete.

This same application is also appropriate in product liability cases where an expert must testify about the mechanics of the product. In such a case, an accurate model of the defective component can be created, then compared to a model without the defect, to illustrate the expert’s analysis of causation. For example, the shape of a bottle’s neck may have been negligently designed, making bottles of that type easy to break and thus dangerous to drink out of.

An expert can present the jury with a model of the defective design, with the accurate shape and thickness, as he explains why the glass is more likely to fracture. He can then present a model of a safe bottle design to drive the comparison home. What’s more, 3D printing can be used to magnify a portion of an item or show full-scale overview, making it easy to highlight subtle features in the product. By giving jurors something tangible to inspect and observe, experts can more effectively educate them on the important details of their testimony.

Accident Reconstruction

3d Printed Accident Reconstruction

Whether the issue is personal injury involving premises liability or a vehicular accident, 3D printing can be extremely useful in reconstructing the scene of an accident. This is useful in cases that involve varied landscapes and structures that are difficult for a person to visualize, and would be prohibitively expensive to model with more traditional techniques.

For example, a mini-model of a damaged car as it was discovered at the scene of an accident can be created if a laser scanner was used to preserve the image at the time of the accident. As an increasing number of law enforcement agencies are incorporating this kind of technology into their departments, preserving images of accident scenes for later replication. According to 3ders.org, the Roswell P.D. in New Mexico recently acquired a Faro 3D laser scanner to capture 3D panoramic images of accident and crime scenes. Sometimes, the complex nature of an accident requires probing into facts beyond those that are easily discernable from just photographs or video. A 3D model helps jurors understand all of the moving parts in an accident, and how they contribute to injuries or demonstrate causation.

In a case involving a structural engineering issue, a scale replica of the structure can be made quickly and cheaply using 3D printing. This enables jurors to see a smaller, but accurate model of a giant industrial crane or scaffold. Especially in large industrial accidents, it is important to pinpoint the cause of the failure and take steps to ensure that a similar accident is prevented in the future. In the context of litigation, a structural model can be of immense help to an expert witness trying to explain the engineering and physics behind the accident. For example, Haag 3D Solutions has created 3D replicas of industrial cranes and placed them in wind tunnels to investigate the influence of wind on a crane failure.

As the technology becomes more advanced and easily accessible, its use to preserve or replicate crime scene details will continue to expand. The scene of a violent home invasion could be captured in perfect detail with 3D scanning, and rapid 3d printing can easily recreate every detail of the scene for the court’s benefit. Though it sounds like a real-life game of clue, this use of 3D printing offers very real benefits.

Forensic Pathology

Forensic Pathology 3d Printing

Extensive use of technology in the area of criminal law is not a novel concept. The field of forensic pathology, the bread and butter of all crime scene investigation shows, often employs techniques such as fingerprinting, DNA matching, and dentition analysis to establish evidence in all kinds of criminal cases. However, the use of 3D printing in the courtroom is starting to bring evidence in this context to the next level.

Now, 3D printing is used to make huge magnified replicas of fingerprints so that jurors can feel and see each individual ridge or swirl and even any small scarring as an expert explains what makes each fingerprint distinct. This transforms the testimony or findings of a forensic expert into an interactive learning experience for the jury, leaving strong impressions. For example, when a  ballistics expert is explaining the bullet trajectory through a wall or worse, a human body, he or she can now utilize 3D printing to offer a model “cut-out” of the bullet’s trajectory and impact. Three-dimensional models will allow the trier of fact to see first-hand specific trauma to an area inside the human body, zeroing in on details as small as scratches and ticks on bone.

So What’s the Catch?

Since the reliability of a piece of “3D” evidence depends on the accuracy of the data, the printer to be used, and the expertise of the modelmaker, 3d printed exhibits can still be somewhat expensive. In a recent Above the Law article by Nicole Black, an attorney is quoted as saying “If you’re not able to settle the case up front and you actually need to create something that can be used at trial, you have to hire even more experts and designers to make sure you’re creating something that would be admissible. Strangely enough, the printer is the cheapest part of the process.”

More to that point, admissibility is a very real legal issue looming in the background of using 3D printing as an evidentiary tool. If a picture is worth a thousand words, then a 3D model might be worth millions. Models can have a lot of psychological power, leading to concerns about evidence that is demonstrative vs. merely illustrative and of course, undue prejudice.

Three-dimensional printing is starting to revolutionize how evidence is admitted and presented in the courtroom as part of an expert witness’ testimony. This method of replicating and presenting facts to jurors actually allows them to personally view and even hold a piece of evidence, making an expert’s testimony much easier to understand.  We have seen just a few examples of how 3D printing is used in medical malpractice, patent infringement, and personal injury cases, but the use of 3D replicas as evidence in litigation is sure to proliferate as the technology becomes more accessible. This will undoubtedly have wide-reaching implications with respect to the rules of evidence and is something to closely track in cases where the admissibility of such evidence is concerned.

About The Author

Mehjabeen Rahman, J.D., is an associate litigator specializing in property and tenant proceedings, debt recovery, bankruptcy, Supreme Court matters, and hearings in Administrative tribunals.