Hugh Borbidge, BSME, Director of Engineering Animation
Synopsis: Engineering animations are an important and useful tool to help explain issues to a jury. This is especially true when there may be a language barrier. For this case, DJS was tasked with completing an engineering animation to demonstrate an incident that occurred when an SUV reversed and struck a gas station attendant.
Scene photographs provided points of rest and a trail of damage left from the event. Witness testimony contributed approximate initial positions of the SUV and attendant with regard to the fuel pumps.
To-scale computer models were built of the SUV, gas station attendant, and the gas station itself. With the available data, we reconstructed the sequence of events and created animation clips showing what had happened. After the motion was finalized, the incident could be viewed from any vantage point. The client utilized two perspective views for this case. Result: Case settled out of court. Hugh Borbidge, BSME, Director of Engineering Animation with DJS Associates, Inc., can be reached via email at experts@forensicDJS.com or via phone at 215-659-2010.
Hugh Borbidge, BSME, Director of Engineering Animations
This animation illustrates a basic configuration of the linkages that steer the wheels when the steering wheel is turned. The steering wheel essentially controls one wheel. The second wheel is connected to the first by a tie rod. This tie rod allows both wheels to steer the vehicle. Should the tie rod fail, the steering wheel would only be able to continue to control one wheel, while the second wheel would be uncontrollable. At high speeds this could have tragic consequences.
Hugh Borbidge, BSME, Director of Engineering Animations with DJS Associates, Inc., can be reached via email at experts@forensicDJS.com or via phone at 215-659-2010.
Lt. Col. Bryan Smith, Construction Site Safety Consultant Case Description: The plaintiff was exiting her relative’s home shower when the shower’s glass door shattered into pieces, and shredded her leg. Expert Analysis: A field inspection was performed approximately three and a half years subsequent to the incident at the request of the homeowner’s insurance company, in order to determine if the plaintiff’s actions were negligent and causal to the incident. Photos and measurements were taken at that time and they evidenced that the shower enclosure door had been replaced in-kind prior to the site inspection. The moveable portion of the shower door was supported by two rollers on a horizontal rail. The rail had cushioned bump-stops at each end of travel.
As the shower user pushed the sliding door open or closed, with more force than necessary to reach the bump stops, the sudden cessation of travel when the roller hit the bump-stop caused the door to rotate in the upward direction. The design of the door hardware included a cam locking device, which was placed below the horizontal track to prevent the track rollers from jumping off the rail. The cam lock device was to be situated and adjusted such that it left a space narrower than the roller’s engagement of the track’s upper surface (see the space between the two yellow arrows). Continue reading “Shattering Shower Door”
Laurence R. Penn, Senior Forensic Animation/Video Specialist ::::
Thanks to powerful software, forensic video specialists at DJS Associates are able to analyze surveillance and dashcam video footage in three dimensions, with high levels of accuracy, in order to reconstruct the circumstances of an accident. Although multiple factors may complicate the process, tenacity and an eye for detail can yield rewarding results. In this case study, the original dashcam video footage showed evidence of lens distortion which needed to be corrected in order to proceed with detailed videogrammetric analysis. After a few phases of lens correction, environment features represented by the red crosses were placed in the undistorted video frame and matched to their locations in the 3D scan data. Once refined the virtual camera is placed accurately within the 3D environment. Trackers represented by the green and yellow crosses were placed on features of the vehicles for each frame in the video. Again, these positions were matched to their relative locations on the 3D vehicle scan data. The final analysis allows 3D vehicles to be placed in the 3D environment spatially and temporally in order to view the circumstances from alternate angles, and even from the operators or eye witness point of view. Laurence R. Penn, Senior Forensic Animation/Video Specialist at DJS Associates, can be reached via email at experts@forensicDJS.com or via phone at 215-659-2010.
Laurence R. Penn, 3D Animations/Technical Assistant ::::
At DJS Associates, we are often called upon to analyze surveillance videos to make a region of interest easier to identify or to re-create the recorded scenario entirely. What may seem like a simple task actually relies on thorough review and consideration of many factors within the footage. Often these factors are subtle and only an experienced technician can identify the clues provided in the images.
With 3D camera matching, evidence and surveillance imagery can be digitally processed and spatially analyzed to reconstruct a scene. Continue reading “Applying Photography, Video, 3D and other Expertise to Forensic Analysis”
Laser scans of the environment and vehicles were utilized to demonstrate how workers could have come in direct contact with a moving trailer. The laser scan of the environment included important information such as the curvature of the roadway, and the curb-to-curb width of the street. Laser scans of construction vehicles allowed DJS to properly place the vehicles on the roadway. With the remaining space, DJS prepared a to-scale pickup and trailer and had it move, according to the laws of physics, and witness testimony. To-scale workers were also placed according to witness testimony. Once all contributing factors to the accident were in place, DJS was able to illustrate, with a reasonable degree of engineering certainty, how the off-tracking movement of the trailer could have contacted the workers, standing nearby. For additional information on DJS Associates’ engineering animations, please contact Hugh Borbidge, BSME or Laurence Penn at experts@forensicDJS.com or via phone at 215-659-2010.
Can you see grass grow? Not by watching for a few minutes but you know it does because it’s higher after a week. It would be tricky to explain this slow occurring event to a jury. A good method to demonstrate it is through time lapse video. But what if it’s something that can’t be filmed?
DJS Associates was recently retained to visually illustrate how water infiltrates concrete slabs and deteriorates structural steel below the surface in an apartment building. DJS utilized photographs and structural drawings to build a to-scale section of the apartment building. Then, through an engineering based animation, DJS demonstrated how water droplets can migrate along a slabs surface, find an entrance, and make its way to unprotected post tensioned cables. Over time, the water can cause the cable to rust. Rust increases the diameter of the cable, putting more stress on the surrounding concrete and often causes the concrete to “pop” or become dislodged near the surface. If left unrepaired long enough, the rust can cause the cable to fail which would compromise the integrity of the concrete slab. For additional information on DJS Associates’ engineering animations, please contact Hugh Borbidge, BSME or Laurence Penn at experts@forensicDJS.com or via phone at 215-659-2010.
Hugh Borbidge, Senior Mechanical Engineer ::::
Are you a good judge of distance? Sometimes not being able to estimate how much room you have can lead to disaster.
In the following case, a man simply walked to his double parked truck and opened his driver side door to get in. At the same time a car carrier was traveling down the street towards the man. Did the man have enough room to open his door with a truck passing by? The whole thing was caught on tape but it was hard to tell how much space was available.
DJS was hired to recreate the scene so we could accurately measure what happened. We collected laser scan data, modeled vehicles and pedestrians and recreated the movement and spatial relationships based on the surveillance video. We were able to determine that had the man waited for the truck to pass, he would have been able to safely open his door and get in. Continue reading “3D Animation: Man Struck by Carrier While Opening His Driver Side Door”
Hugh Borbidge, BSME, Director of Engineering Animations ::::
There are many ways to re-create vehicle movement in a 3D computer environment. Some methods are better than others. We will talk about 3 different methods; simple, rigged, and physics based.
The simple method is the easiest and fastest method as the name implies. The vehicle is treated as one object. The chassis and wheels do not move independent of each other. They all move as a unit. In the image above, the red lines represent the tire paths. You can see that the front and rear tires follow the same path even as the vehicle makes a turn. This is not scientifically accurate but can sometimes be useful for a “down and dirty” review for things like basic spatial relationships. Continue reading “Recreating Vehicle Movements: Update from our Engineering Animation Department”
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