What is it like to 3D scan fossils in a hot African desert?
Our paleontological mission is almost complete, and it’s time to draw some conclusions and say a few words about the tech side of 3D scanning in the pretty extreme conditions of the African savannah.
1. No stable power supply
The battery for the scanners proved to be invaluable; it lasted for two days and still wasn’t used up. Here’s a trick that reduces energy consumption greatly: every time between scanning sessions disconnect the scanner from the battery because energy is consumed even in standby mode.
2. The heat
The second obstacle we faced was the heat, but our scanners performed just fine. We were bracing ourselves for the worst, but neither Eva nor Spider ever overheated, even though it was about +35 °C. The longest scanning time with Eva was about 400 seconds; then I paused, saved the project, and checked if we missed anything. The laptop overheated and created some problems, but mostly for the operator – I wish we'd had a laptop harness. It would have been easier to scan on a tablet, but then we would’ve needed to make pauses often to save the tablet’s RAM and upload the data we recorded.
3. Direct sunlight
I already mentioned briefly that scanning under intense midday sunlight is very difficult, almost impossible. We had to move the skull of the giant crocodile away from the sun into the shadow of some rocks. If you have to scan under bright sunlight, create some artificial shade, for example, with an umbrella. Soft sunlight, however, is not a problem.
4. Sand dust
Sand particles blown by the wind could theoretically cause some trouble, which is why we kept the scanner in a bag and covered the laptop with a piece of cloth during breaks.
All in all, for the next scanning expedition in a desert I’d take:
- a parasol
- a battery for the scanner
- several spare batteries for the laptop
- a laptop harness
- a laptop with 32 GB of RAM or SSD
Last, but not least, I’d take Eva and Spider, of course. They’re really very convenient for scanning in the field. One of the biggest advantages is that they are handheld and fully portable. Just take a look at the 3D model of the crocodile in the screenshot below. The crocodile’s ribs were very difficult to capture, simply because we had to scan almost from beneath the ground to “see” the reverse side.
Eva is very handy for scanning a large area within just a few minutes, and Spider should be used for the details. Because both scanners did the job so well we took just two days to scan four sites, almost three days ahead of the original plan.
Another very helpful feature is Continuous Scanning mode. It automatically “sews” together the 3D scans during scanning and restores registration from any location. Though the ground at Turkana may look homogeneously brown, the algorithm recognizes it perfectly and uses it as a texture marker.