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3D laser scanning revolutionizes construction site accident investigation and evidence collection

In early October 2012, several construction workers were killed or injured when the Miami Dade College parking garage collapsed like a pancake, trapping a then-unknown number of workers inside (See http://tinyurl.com/9956xae). Some survived, but some did not.

Post-accident site investigation

Since this tragic loss of life, injury, and property damage, lawyers have no doubt already begun what will be expensive and lengthy litigation. The owner, architect, engineer, contractor, subcontractors, construction workers and their families will all play a part.

The evidence may be sifted and sorted for years before any judges or juries hear about what happened on that fateful day.

Ideally, each party would have ample opportunity to investigate the site, take measurements, and form opinions as to what happened. However, this was not an option in Miami.

Workers needed to be freed. The structure’s potential for further collapse endangered all those around it. The owner had a dangerous pile of rubble where a new parking garage was supposed to stand. Certainly, nobody wanted to preserve site conditions for any length of time.

So, how can evidence of existing site conditions be preserved forever? 3D laser scanners were dispatched to the site immediately.

From onsite scan to a 3D model on your computer

Similar to traditional surveying, 3D laser scanners are set-up on tripods and use light to precisely measure their surroundings. But whereas traditional land surveying instruments take only one measurement at a time and need a reflector to return the light, 3D laser scanners take millions of measurements of everything that they can “see”  within 300 feet.

This data is collected in a matter of minutes and the instrument can be set up as many times as necessary to see the entire site. Technicians then convert this raw information into a 3D model.

Lawyers and their experts can use this model to return to the day of the accident at any time.  They can pan and zoom around the model to find any desired vantage point. Any angle or distance can be measured and re-measured.

Collecting quality evidence

After any given construction accident, investigators take photographs, make measurements and sketches, and interview witnesses.  However, even the most seasoned investigator can miss critical details due to time constraints, site access, or simple knowledge of the facts.

Once the site is cleaned up or altered in any way, the evidence is spoiled. However, 3D laser scanning allows investigators to return to the site at any time to retrieve missed or forgotten details.

Additionally, the evidentiary quality of 3D laser scanning data far outweighs traditionally collected evidence. Photographs provide only a single 2D perspective and each detail must be specifically targeted. Manual measurements are subject to observational and recording error.  Witnesses certainly cannot permanently remember every visible detail, especially in the wake of a tragedy. 3D laser scanning overcomes all of these limitations.

Full access to the site is often limited, for example, from the danger of additional collapse and loose rubble around the parking garage in Miami. This problem is also overcome with 3D laser scanning, as it uses light to measure from a distance. Anything that can be seen can be scanned and recorded for later review.

Using the model at trial

3D laser scans are not new to the courtroom and readily pass muster under evidentiary challenges. Foundation for entering a 3D laser scan on the record can be laid by a professional land surveyor, but courts nationally have allowed scans based on the testimony of laymen who were simply certified to use the equipment.

At trial, 3D laser scans provide unparalleled demonstrative exhibits. Judges and juries will no longer need to travel to visit a site.

As noted by Lt. Warren Hamlin of the Knox County Tennessee Police Department, “It’s almost like taking the jury right to the crime scene. We can show pictures all day long, but when you’ve got a panoramic view that shows exactly how it looked and where everything was, that’s a much better depiction than a photograph. … So, if a guy says, ‘I was standing in that corner,’ you could create a viewpoint exactly where his head would be and look around the model and tell whether, yes, he could see that, or, no, he’s lying.”

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David Headrick has over 14 years of experience in the surveying, engineering and legal industries, both as a project manager for LandAir Surveying and as a lawyer in private practice. He has represented numerous land surveyors, designers, architects, contractors and other industry professionals throughout his career. Today, David serves as an executive and project manager for LandAir, focused on developing and managing the company’s 3D laser scanning department. Contact him at dheadrick@lasurveying.com.

 

 

 

3D Laser Scanning: The New Industry Standard

When we first started laser scanning back in 2005, we replaced some of our total station surveying equipment with high definition scanning technology. As much as anything, this was a great way for us to learn how to use the technology and understand its capabilities and limitations.

Early on, much of the work we did involved transportation projects and large complicated intersection surveys. There were many immediate benefits. For one, our surveyors were no longer put out into traffic and in harm’s way.

Another benefit was that we didn’t have to drive across town or across the state just to check on a few ambiguous points in a survey. Instead, we could just go back and look at the point cloud.

Today, in 2012, the entire scanning world has changed. In addition to the use of laser scanning in architectural and engineering design and construction, this technology is now regularly used by insurance companies and law enforcement agencies for crime scene and accident reconstruction.

While before we had to convince clients of the benefits of using laser surveys, we now have a growing client base that simply will not consider starting a project without one.

In addition to providing accurate spatial information to the forensic engineering, law enforcement, criminal defense, architectural and construction industries, laser scanning saves both time and money.

Here are four primary reasons 3D laser surveys, or high-definition scanning, is quickly becoming the new industry standard when it comes to making precise measurements in complicated environments:

Reason #1: Scanner Speed

The speed of scanning has changed dramatically compared to what it was just seven years ago.

The first scanner we purchased (and still use today) took one hour for a 360-degree spherical orbit. Today, with our current scanners, it takes just six minutes. This speed enables us to take many more scan set-ups than we used to take.

With our phase-based high speed scanner, we can now get 40 to 60 scans per day, which is very adequate to cover a large two-story mechanical room. To get the same amount of scans seven years ago would have taken a week.

In areas like these, it is the detail we look for, not the range. In extremely complicated areas, we make a set of scans on all sides.

Reason #2: Software Improvements

Improved software programming has also contributed to the widespread acceptance of high definition scanning technology.

I remember talking to clients back in 2005 and our message was something like this, “We will scan for you, then give you a 2D deliverable set of drawings that you can use to design your project.” When they would ask if they could use the point cloud in their design, our answer was always the same: “Yes, but you will have to buy $10,000 worth of software.”

As you can probably imagine, this was not an easy sell.

Fortunately, today Bentley, AutoCAD and Revit all have point cloud engines in them. The difference between an engine and a viewer is that we can now load a point cloud into an “engine” for a client and they can use the data in the design without having to purchase expensive “point cloud” software.

In fact, one of the takeaways from a scanning conference I recently attended was that all of the major software providers are moving to full 3D software design systems. They finally understand what we have known for years. Why would you survey in 3D, flatten the data to 2D, design in 2D then build in 3D? It just doesn’t make sense.

Reason #3: Clash Detection

This alone is worth the cost of a 3D laser survey.

Consider that if a project is modeled in the design phase, the completed final design – including the MEP systems, air handling systems, structural system and all of the architectural design – can be placed within the point cloud and clash detected. Anything that interferes with another system can be seen immediately and corrected before construction.

This is huge! What prudent engineer, designer or contractor would not want this advantage?  How important would this be to an owner?

Reason #4: TrueView or 360-Degree Spherical Photography

This technology has also improved quite a bit in the last seven years. When we first started scanning, we were fascinated with the fact that scanners could take photographs of the surrounding area, and then take that photographic data and overlay it with the scan data to make general measurements to the environment.

Unfortunately, back then the on-board camera was not as good as we had hoped and sometimes the pictures would come out octagonal and disjointed. As the process became more refined, we were able to mount a high resolution camera on the scanner and produce a crystal clear, color spherical photograph of the site.

This is a big step because it allows you to view a site from any scan set up. You can add text and information to the photographs and then e-mail a specific view to another agency across the country or across the world. (In this case, some of our clients pay for our scanning fees with their savings in plane tickets!) This tool also enables clients to look out from the center of every scan and saves lots of time and discussion as to what is or is not located in the area of interest.

High definition scanning has quickly evolved from an emerging technology to an industry best practice when it comes to complicated crime scenes and accident reconstructions. The investigation process, similar to the construction process, always includes many unknowns and the chance of errors is always high.

Why put yourself in the position of having to explain how an investigation was slowed down or compromised because a laser scan was not the foundation of the project?

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Tate Jones has over 40 years of experience in land and aerial surveying and was one of the country’s earliest adopters of 3D laser scanning technology. A nationally recognized expert in the field of 3D data capture, he has worked with hundreds of clients in the forensic engineering, law enforcement, criminal defense, architectural and construction industries. Contact him at tjones@3DForensicScans.com, a division of the LandAir Surveying company.