Category : 3D Animation

3D Collision Reconstruction – A Dashcam Video Case Study Breakdown

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 or via phone at 215-659-2010.

Applying Photography, Video, 3D and other Expertise to Forensic Analysis

3D Camera Matching in Engineering Animations

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.

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Engineering Animation: Watch How Workers Could Have Come in Direct Contact With A Moving Trailer

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 or via phone at 215-659-2010.

Engineering Animation: Water Infiltrates Concrete Slabs and Deteriorates Structural Steel

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 or via phone at 215-659-2010.

3D Animation: Man Struck by Carrier While Opening His Driver Side Door

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.

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Recreating Vehicle Movements: Update from our Engineering Animation Department

1 Engineering Animation Vehicle Path

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.

Engineering Animation Vehicle PathThe 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.

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