3D Printing: A New Dimension of Expert Testimony

Three-dimensional printing is transforming the way attorneys and expert witnesses present demonstrative evidence in court. By creating precise, tangible models of injuries, products, and accident reconstructions, 3D printing allows jurors to see—and even hold—key pieces of evidence that might otherwise be difficult to comprehend. This cutting-edge technology enhances expert testimony, making complex concepts more accessible and persuasive. As 3D printing becomes more widely available, its role in litigation continues to expand, offering a powerful tool for illustrating crucial case details with unprecedented clarity.

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 them 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.

The Evolving Role of 3D Printing in Litigation

Three-dimensional printing has transitioned from an emerging technology to a widely adopted tool across industries, including law, medicine, and engineering. Today, attorneys and expert witnesses increasingly rely on 3D-printed models to present demonstrative evidence in court with unparalleled accuracy and detail. Modern 3D printers are faster, more affordable, and capable of producing highly detailed models using an expanded range of materials, including advanced polymers, metals, and even biological tissues.

One of the most significant advancements in recent years is the increased availability of high-resolution 3D scanning technologies. Digital photogrammetry, laser scanning, and structured light scanners have dramatically improved the precision of 3D-printed evidence. As a result, attorneys can now present more detailed anatomical models in medical malpractice cases, reconstruct accident scenes with greater accuracy, and provide jurors with tangible representations of intricate mechanical components in patent disputes.

Additionally, the cost of 3D printing has continued to decline, making it more accessible for legal professionals and forensic experts. While early adoption of the technology required significant investment, many law firms and litigation support companies now have in-house 3D printing capabilities or can access affordable on-demand printing services. This shift has allowed attorneys to integrate 3D-printed models into their case strategies more frequently and cost-effectively.

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

When 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 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.

Patent Infringement and Product Liability Cases

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 a 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

Whether the issue is a 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. 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.

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

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 an 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.