This article was recently published by LLF attorney Kristi Schubert in the Louisiana Association for Justice publication, “Louisiana Advocates.”
Bring your Case to Life with 3D Printed Evidence
Three-dimensional “3D” printing is a process of turning digital 3D models into real physical objects. The technology is becoming mainstream in many sectors. In the medical field, places like Ochsner are using 3D printed models of patient anatomy to plan surgical procedures and to educate patients about their health. In law enforcement, 3D printing is being used to aid in forensic investigations.
Despite its obvious potential as a powerful visualization and teaching tool, 3D printing has yet to become standard in the courtroom. In 2015, in one of the first uses in England, prosecutors used 3D printed evidence to obtain a conviction of a man who had dismembered his victim with a saw. Prosecutors needed to show the jury that the victim’s bones, when viewed up close, showed traces of saw marks. They could not introduce the actual bones due to health concerns, as well as concerns about the emotional impact on the jury and the victim’s family.[i] Instead, prosecutors used scanning technology to scan the bones and 3D print perfect replicas. The jury could then see the saw marks as they held the replicas in their own two hands.[ii]
What follows is a summary of some basic information you’ll want to know when considering using 3D printed evidence in your own cases.
The Cost of 3D Printing:
The cost of a 3D print object varies based on two factors. The first factor is the time required to prepare the digital file for printing. If you can provide the printing company with a print-ready file at the outset, you can save a substantial amount of money. If you cannot, a 3D printing company may charge a rate of around $50-$100/hour for the time spent preparing the file. The amount of preparation needed varies based on the complexity of the print and the type of data you provide.
The second factor is the type and amount of print materials used. Many print companies charge by the cubic centimeter of material consumed in the print. The price of the materials varies greatly by type. Items can be printed in plastics, resins, metals, nylons, and sandstone. Some materials can be printed in color. More than one material can be combined into a final product, as depicted in these photos of 3D printed objects. Simple materials like plastic can provide great accuracy at a low cost, but the item won’t have the weight or feel of a more expensive material.
Speed of 3D Printing:
3D printing is quite fast. For example, Entrescan, a New Orleans printer with whom I recently consulted, can typically produce a finished product within 2-4 days after receipt of a print-ready file. If you are unable to provide a print-ready file, it may take anywhere from one to four weeks, depending on the complexity of the print.
Size of Print:
3D printing provides you with the unique ability to produce accurate-to-scale replicas of an object at various sizes. Items that are too large to bring to court can be printed as precise miniature replicas. Items that are too small to be seen from afar can be printed as detailed larger-than-life recreations. When deciding on the size of a 3D print, keep in mind that you are charged by the cubic centimeter of material consumed, and thus the cost increases exponentially with the size of the print.
Duplicating Original Items of Physical Evidence:
Physical items of evidence (e.g. the shoe a client was wearing when he fell or the defective machine part that malfunctioned) can be scanned and duplicated. Current scanning technology has a resolution of as much as 43,000 times greater than regular CT-scan imaging. The duplicates created from such scans can be extremely accurate.[iii]
Printing Your Client’s Injuries:
Your client’s 3D medical image data from MRIs or CTs scans can be used to print a 3D replica of their actual bones, tissue or organs. This could be particularly helpful in cases involving disc injuries. Imagine being able to provide the jury with a perfectly scaled model of your client’s own bulging disc. They can hold in their own hand and compare to an equally sized model of a healthy disc. To print your client’s injury, you will need to obtain the DICOM data. Many health care providers purge the original DICOM data after a few weeks, so you will want to request it as soon as you possibly can. A 3D print created from DICOM data will often be accurate enough to introduce as substantive evidence. It is merely a 3D representation of data collected from already scientifically proven technologies. However, even where a judge is unwilling to accept the 3D printed model as evidence, it should be allowed as a demonstrative aid.
Where you do not have MRIs or CTs, a 3D designer may be able to the 2D medical images (e.g. x-rays/ultrasounds) to recreate an approximate model of the injury. However, such a recreation would only be suitable as a demonstrative aid.
Printing Architectural Models of Accident Sites or Buildings
Lawyers have been using architectural models in the courtroom for years, but with 3-D printers, you can typically do it faster, cheaper, and with more accuracy. Models of an injury site can be created using the computer aided design (CAD) file, or based on measurements taken at the location. Once you have the 3D model, you can print it infinite times in various sizes. You could provide your expert witness with one large version, and provide each juror with their own smaller version so they can follow along. Depending on the material used, you can request that a witness draw directly onto the model, such as by putting an X at the location they were standing when they witnessed an injury.
Obtaining a Print-Ready File and a Cost Estimate for the Print
In a recent case, where my client sustained a severe femur fracture after falling from his second floor apartment building due to the negligent removal of a guardrail, I listed the following 3D printed items as exhibits: “(1) 3D printed reproduction of the building, (2) 3D printed replica of the plaintiff’s broken femur, and (3) 3D printed replica of the rod and screws which were implanted in the plaintiff’s leg.” At the pretrial conference, the judge indicated willingness to admit all three items of 3D printed evidence so long as it was presented to opposing counsel well in advance of trial.[iv] What follows is a summary of how I obtained a CAD file and estimate for the cost of printing the building.
Print-ready files are typically in the .STL or .OBJ format. However, if you are unable to obtain a .SLT or .OBJ file, printers will often be able to accept exports from any major CAD program (Revit, Solidworks, Inventor, etc) and convert them into a print-ready format. In my case, I obtained the blueprints of the relevant building and attached them to the following request for production:
Please produce an electronic copy of the computer aided design (CAD) file (e.g. Revit, ArchiCAD, AutoCAD, Chief Architect, Rhino3D, CATIA or any other CAD software) used to produce the attached blueprints of the plaintiff’s apartment building. If feasible, please produce the requested information in the form of a .STL or .OBJ file.
In case the defendant refused to provide the CAD file, I also sent the following interrogatory:
Please explain the method by which the attached blueprints were prepared, and if they were prepared using computer aided design (CAD) software (e.g. Revit, ArchiCAD, AutoCAD, Chief Architect, Rhino3D, CATIA or any other CAD software), please identify which software was used, what format the blueprint files were stored as, and the current location of the file used to prepare them.
Once you know how the files are stored, you can ask the judge to order their production by pointing out that the requested files are kept in a 3D file format in the regular course of business, are easy to access, and can be easily and inexpensively produced. I recommend you start early, because you may need to send several rounds of requests to get what you need.
Having obtained the CAD file, I requested a price estimate from Entrescan. I asked them to print a model of the first two floors of the building, including the outdoor stairs leading from the second to the first floor. I asked that the model be printed in white plastic and that it be 8 inches tall. I also requested that the guardrail at the top of the stair landing be detachable. I was unable to obtain a print-ready file before the discovery deadline passed, so I would need to pay them to get my file print-ready. They estimated the cost to prepare the file would be approximately $1,500, and that the materials would likely cost around $2,000. Thus, the total expected cost for my model would likely be $3,000 – $4,000. They expected it would take 2-4 weeks to deliver a finished product.
My case settled several days after the pretrial conference, so I was never able to submit the 3D printed evidence. However, given the nearly endless possibilities afforded by 3D printing technology and the comparatively reasonable price, I suspect I’ll have many future opportunities to utilize this powerful tool in the courtroom.
[iv] The case was set for trial in Louisiana’s 24th Judicial District Court.