In 2010, the team that would become RSET was asked to take 3D scanning technology somewhere it wasn’t normally designed to go: 80 feet beneath a Missouri field, into a recently discovered cave.

What followed became one of the more unusual reality capture projects we’ve ever been involved with.

A Discovery Beneath a Missouri Field

The cave was discovered after a sinkhole opened in the middle of a field. When one of the first people rappelled into the opening to explore what was below, he noticed something unexpected: footprints, and what appeared to be evidence of human activity.

Rather than disturbing the site, the decision was made to bring in experts to investigate.

The site became known as Lon Odell Memorial Cave, and we were invited to participate by CAIRN, a Missouri-based team of archaeologists involved in documenting caves and archaeological sites. Our job was to determine whether emerging 3D scanning technology could help document some of what had been preserved underground.

Building a Scanner for the Cave

This was 2010. Portable 3D scanning technology was very different from what we have available today.

For the project, we constructed a ruggedized structured-light 3D scanner based on research by Dr. Larry Hassebrook at the University of Kentucky. The equipment had to survive transportation, an 80-foot descent, mud, moisture, darkness, and the generally unforgiving conditions of a cave.

We were also joined by Dr. Chris Begley, an archaeologist from Transylvania University.

We loaded up the equipment and drove to Missouri without knowing exactly what we were going to encounter underground.

Eighty Feet Down

Getting to the site was an adventure by itself.

We rappelled approximately 80 feet through the sinkhole into the cave. Once the team was below, the scanning and documentation equipment had to be carefully lowered down after us. Then we started exploring.

The cave was spectacular.

There were stalactites, stalagmites, columns, bear tracks, human footprints, and an extraordinary amount of mud. Everywhere we looked there were geological features worth documenting.

But the footprints were particularly interesting.

Using our structured-light scanner, we captured selected footprints in 3D. The resulting digital models preserved their shape and surface detail without requiring us to remove the original impressions from the cave. We were then able to take those digital scans and 3D print physical reproductions of the footprints.

Today, scanning an object and immediately thinking about creating a digital model or 3D print may seem fairly routine. In 2010, doing this with archaeological evidence at the bottom of a cave was a very different proposition.

Evidence of Earlier Visitors

The archaeologists believed that the cave may have once had another accessible entrance, and that people could have entered it on foot centuries earlier.

There were markings on the cave walls that were particularly intriguing. Based on the archaeological investigation and dating of material associated with the site, some of the markings were believed to be more than 700 years old.

One interpretation was that some markings may have served almost like breadcrumbs, helping people navigate through the darkness and find their way back out of the cave.

We also documented what appeared to be a possible cave drawing or symbolic figure. Its exact meaning was uncertain, but it added another fascinating element to the evidence of human activity within the cave.

Reading the Cave’s History

The geology told its own story.

Evidence suggested that portions of the cave had flooded repeatedly over time. Water had worn down some of the formations on the cave floor, including stalagmites.

Combined with the archaeological evidence, the researchers believed the cave environment had changed significantly over the centuries. An entrance that may once have allowed people to walk into the cave was no longer accessible, leaving the modern sinkhole and vertical descent as our way in.

That meant the footprints and markings weren’t simply interesting objects. They were pieces of a much larger puzzle about how people had entered, navigated, and used this underground environment hundreds of years earlier.

When the Batteries Run Out

We continued scanning and documenting until eventually we encountered the limitation that every field technology project faces sooner or later: we ran out of power.

There weren’t exactly any electrical outlets 80 feet underground.

With the scanning finished, there was still one final challenge. We had to get ourselves and our equipment back to the surface. After spending the day underground, that included making the approximately 80-foot climb back out using a rope ladder.

It was a memorable ending to an already unforgettable project.

From a Missouri Cave to RSET

The project combined many of the things that would eventually become central to our work at RSET: 3D scanning, archaeology, documentation, visualization, experimentation, and taking technology into environments where conventional methods aren’t always practical.

More than anything, it demonstrated something we’ve continued to see throughout our work.

Sometimes it’s about preserving evidence of a moment that happened hundreds of years ago, and allowing researchers and others to examine that evidence without disturbing the original.

The Lon Odell Memorial Cave project was documented on video and later featured on The Archaeology Channel under the title Footprints Beneath the Earth.

More than 15 years later, it remains one of the most fascinating adventures we’ve had with 3D scanning technology.