Tom Greaves, Chief Marketing Officer - DotProduct LLC
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It is a long story but Covid-19 drove me to find a way to store my 15,000 pound displacement sailboat in my driveway this summer, at least until Maine, where I usually keep her reopens to “people from away”.  Big problem – I need my driveway for our vehicles, so the solution was to extend the driveway.  The paving contractors we called were all very nice and had great references, but this thrifty Yankee had sticker shock.  I estimated I could do the project myself for one third the cost, including materials. The cut part of the project was to remove the topsoil down to 9” depth over a 15’ x 25’ area.  The fill part of the project was to lay down 3/4” pack gravel in the volume previously occupied by the topsoil.

Dot3D Pro to the Rescue
My trusty DPI-8S running Dot3D Pro V3.3.1 helped me verify the fill quantities.  The problem with ordering too much gravel is that it is not so easy to get rid of any surplus.  My wife was not enthusiastic about starting a gravel pit in the back yard.  Order too little gravel? Then you’re faced with ordering more and the transportation cost adds up. 

Step One – the cut operation
This is a great country. I easily rented a Takeuchi TB230 Compact Excavator and my son Garrett and I got the excavation done in a couple of hours.  This included learning how to operate the equipment from a cold start.  The power of the opposable thumb on the bucket makes you feel superhuman.  I bow to the experts who operate this equipment and bigger every day, of course with much more efficiency.

​Step Two – Volume Measurement
​I had staked out the area of interest using a tape measure and string and marked some stakes with the 9” desired depth to guide the excavation. Next, I scanned the pit with my DPI-8S – see Figure 2 and then I used the volume calculation tool to estimate the excavated quantity. The tool calculates the volume between the base of the excavated surface and a plane fit to the four corners of the top surface of the hole.  The plane elevation can be adjusted manually too.  See Figure 3.

It turns out you order gravel by weight, not volume.  The conversion used locally is 1.4 tons per cubic yard so I ended up ordering 15 tons which corresponds to a volume of 289 cubic feet.  I could not determine if the volume weight conversion applied to packed gravel or unpacked, however.

Step Three -  Fill Operation
I confess I felt a thumping in my chest when the gravel truck showed up. The operator was very skilled and helped as much as possible to distribute the load.  I covered the bottom surface with landscaping mat to prevent weed growth prior to laying down the gravel. 
The tried-and-true armstrong method was used spread the remaining gravel.  Many thanks to my son Garrett and daughter Emma for helping me with the shovel work. 

Figure 5 shows the end result.  I compacted the gravel by driving over it with a two-ton SUV and the elevation matched better than I’d dare hope.
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Conclusion
Handheld scanning provided a fast, accurate way to estimate hole volumes for small projects like this.

​Billy Bush, a District Lead Reconstructionist for Oregon State Police’s Collision Reconstruction Unit testified at Hendricks’s trial following his investigation. The defense claimed he was the passenger in the vehicle, not the driver, and therefore was not responsible for the crash or the loss of Mayhak’s life. Three years after the incident, Bush, an ACTAR accredited Reconstructionist, reopened the investigation when the defense successfully moved to exclude the admission of expert testimony from a non-accredited CRU member who had led the investigation in 2016.
 
Following Bush’s investigation, the core of the prosecution’s case was showing the vehicle dynamics, occupant kinematics, and Principle Direction of Force excluded the possibility of the passenger surviving the crash. Consequently, the survivor was ultimately determined to be the driver.
 
Bush obtained a search warrant for the vehicle, which was kept as evidence and used a DT Research DT301X-TR tablet equipped with an Intel RealSense D415 sensor and Hemisphere GNNS sensor and running DotProduct’s Dot3D Pro software to produce a 3D point cloud of the wrecked vehicle. First, four AprilTags were positioned around the vehicle and their centers were surveyed with centimeter grade accuracy using the Hemisphere dual-frequency GNSS sensor onboard the tablet running Leica Evidence Recorder software. The AprilTag coordinates were then imported to DotProduct Dot3D Pro for post-processing of the point clouds collected with Dot3D Pro using the RealSense D415 sensor. According to Bush, it would have been impossible to use a tripod laser scanner effectively for the data collection because of the proximity of nearby vehicles and obstacles in the evidence yard. Storage space is at a premium and vehicles are stacked close together.

​The crash reconstruction showed that the vehicle had hit a tree on the passenger side and that the tree had ripped off the passenger-side A-pillar and roof. It was also determined that the cargo partition behind the passenger had been displaced to the rear and the passenger had been caught in the path. At the trial, Bush used the Dot3D Pro software to show the jury the force lines and vehicle crush navigating in real-time to multiple points of view, including perspectives from the front of the vehicle looking back, the side of the vehicle looking in and the top of the vehicle looking down. Bush measured the deformation caused by a tree impacting the front of the vehicle matching this to the tree diameter and damage orientation. Using the point cloud data and after extensive cross-examination, Bush established for the jury that beyond a reasonable doubt, the passenger had perished in the crash.

Herein lies the power of point clouds for crash reconstruction. The reconstructionist can bring the vehicle to the jury and show it from any point of view. Often it is not practical to take the jury to the crash scene or the evidence yard and even more challenging to show jurors the evidence from the same point of view. Photographs and video presentations are necessarily limited to the point of view of the camera at the time the images are collected. Viewing the data from the top of the vehicle, for example, would not be possible with photographs unless the scene photographer had thought to photograph from that vantage point. The interpretation of point clouds can be restricted to real-world measurements, unlike animations. In this trial, while the judge excluded IIHS videos showing exemplar crashes, he admitted the Dot3D vehicle point cloud after defense objections were met with responses further establishing its scientific foundation.

Of course, the defense also has to have access to the data without the burden of having to purchase expensive proprietary software. Standard operating procedure for the Oregon State Police is to provide industry-standard outputs including PTS, LAS, LAZ and E57 files, all of which can be exported directly from Dot3D. OSP also provided the defense the DotProduct binary .dp file and link to the company’s free viewer. According to Bush, this standard operating procedure more than satisfies discovery requirements.

More Information
More information about the incident can be obtained for a modest fee from the Oregon State Police Central Records Section citing OSP Case# SPI6 224289.