Capture, Destroy, Rebuild: Re-creating Chaos (in 3D)

I’m not writing about a metal band, but about photogrammetry and 3D printing.

Accidents happen, safety has to be restored, forensic experts need to act fast.

To speed up the accident documentation process, experts are using drones and photogrammetry software to reconstruct accident scenes in the form of accurate 3D models. Fast documentation means fast cleanup, so traffic conditions can return to normal in minutes instead of hours, as described in 4 Reasons Drones will Revolutionize Accident Scene Response.

Real world 3D models: from physical to digital, and from digital back to physical
Accident scenes, and other temporal structures like installation art or urban interventions, are ephemeral. Why not capture them, store them as digital 3D models, and bring them back to the physical world for professional analysis or aesthetic enjoyment?

We decided to 3D print a car crash following a path that matches the Forensic 3D Printing Workflow, written by Eugene Liscio, P, Eng. Just for the record, these heaps of twisted cars below are part of a forensic training exercise, not a real car crash.

Capturing Images

Circular drone flights captured the 67 images we used as input to create the 3D model.

With the Pix4Dcapture app you can create flight plans optimized for data capture

A 3D model from Pix4D software

Pix4D offers desktop and cloud photogrammetry software solutions to create 3D models from images. The software identifies unique points in images and builds 3D point clouds, which are then used to create outputs such as textured 3D meshes and orthomosaics.

Pix4D exports meshes in different file formats, including OBJ and FBX, the most popular for 3D printing.
3D model from Pix4D software

Editing the model for 3D printing

To define the printable area, we edited the densified point cloud in Pix4D desktop software, cropped it in a rectangular shape, and then generated a mesh.

Cropping the model in Pix4D software

In case you processed your model in the Pix4D cloud, you can just download the mesh and edit it using a software like MeshMixer or MeshLab.

Adding a base and making the model print-ready

To add a base and make our model printable, we imported our OBJ mesh into 3D Builder, a free Microsoft 3D modeling software.

We extruded the mesh down to give thickness to the base surface

Once we gave thickness to the base, the mesh became watertight (manifold), and was ready to print.

3D Printing

We printed the model with our LULZBOT TAZ, a hobby-grade desktop 3D printer.

Printing took 3 hours and 16 minutes

Our 3D printed car crash is ready!

Here is our 25-gram 3D model. Isn’t it creepy cute?

3D mapping and printing in different industries

Leaving aside car crashes and forensic applications, 3D mapping is a way to digitally preserve ephemeral structures, for instance, buildings that have to be demolished, like the Domino Sugar Refinery Factory in Brooklyn.

In the design world, the combination of 3D mapping and printing are helping develop ideas faster than ever, from architectural models to industrial design prototypes.

Is there something you would like to capture and preserve, exactly as it is now? Take the real world, preserve it digitally, and bring it back to life.


Give it a try: Test Pix4D software and start 3D mapping today!

If you don’t own a 3D printer, you can upload your model to a 3D printing platform (e.g. WhiteClouds, Shapeways, or 3D Hubs) and get it printed in different kinds of materials, with the finishing and colors you choose.