UNL Engineer Creates 3D Map of Robber's Cave In Lincoln

A look deep inside Robber's Cave. (Photo by Craig Chandler, UNL Communications)
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February 6, 2020 - 6:15am

Robber's Cave in Lincoln has a lot of history. It's 5,600 square feet of meandering tunnels and stairways. It's served as a storage area for a brewery, a place for secret societies to meet and as somewhere youth have gathered for more than 100 years. A University of Nebraska-Lincoln assistant professor has spearheaded a 3D rendering of the entire cave. A new effort is also underway to try to get Robber's Cave on the National Register of Historic Places. NET's Brandon McDermott spoke with Richard Wood about his mapping project.

Brandon McDermott, NET News: Tell us about the historical importance of Robber's Cave in Lincoln.

A ghost face etching in Robber's Cave. (Photo by Craig Chandler, UNL Communications)

Richard Wood, Department of Civil and Environmental Engineering at UNL: Robber's Cave has served as both a storage facility for an outdated brewery, as well as a social and gathering place for many organizations both formal and informal in the Lincoln community.

McDermott: History Nebraska is hoping to nominate Robber's Cave to the National Register of Historic Places. Did History Nebraska reach out to you about this potential project and how has it been working with History Nebraska?

Wood: Things have been working great, the communication is very open. They actually did not reach out to me directly. I was put in contact with them about two years ago, the idea of nominating Robber's Cave as a national monument. The discussion started about pick up. Given the delicate nature and the detailed nature of the caves, they saw some work done with LIDAR and was like, ‘Oh, that might be a very interesting, a very efficient way to document the caves.’

McDermott: You said the LIDAR, is that what you're using to 3D map this place?

Wood: Correct. What we use to 3D map this was actually ground-based or terrestrial LIDAR. It's mounted on a tripod and we were able to move this throughout the cave for about 92 positions.

McDermott: How long did it take to set this tripod up in those 92 different positions?

Wood: Yeah, it took about three solid days of scanning. Since it was underground, we were pretty much insensitive to the natural lighting. So we essentially lost track of time. But we were able to capture all of it in three in three days.

A top-down view of Robber's Cave. (Courtesy of Richard Wood)

McDermott: And this isn't just going in there and taking some pictures. I mean, this was a complete 3D rendering of the entire cave. There's some carvings in there that you guys want preserved. Talking about these carvings, who made these that you know of and when were they carved?

Wood: So they were etched throughout the history of the caves as early as the 1960s and much earlier and one of the famous carvings is one of the Scarborough carvings. They were the landowners through the 1960s that actually started to take this cave and use it as a tourist attraction.

McDermott: From the time you started this project to finishing, I mean, I'm sure you saw a lot more etching-wise, a lot more carving-wise then you knew about. Tell us about some of the more interesting ones other than the Scarborough edgings.

Wood: So, to me, one of the more interesting carvings was that of a Sphinx, which actually serves as almost a secret society for some organizations at the University of Nebraska-Lincoln. There's other carvings as well. The Sphinx is kind of cool, because the depth, the relief of it. But there's a lot of eyes, there's some animals, there's some people carvings, as well as many, many names.

McDermott: There's also a ghost carving as well?

Wood: Correct, there's also a ghost face. It's quite diverse. In the main parts of the cave, almost every square inch of it has some type of carving.

Richard Wood works on the 3D rendering of Robber's Cave. (Photo by Craig Chandler, UNL Communications)

McDermott: The cave itself at Robber's Cave, it's deteriorating, that material inside. What were some of the challenges that you faced in 3D printing the entire cave?

Wood: The biggest challenge we faced was detail. Our goal was more than just producing a 3D map or a 3D rendering of the cave. We also wanted to be able to capture the ornate details and the engravings. That actually, is what required us to spend so much time in the cave. We had to do it at many different angles, such that you can see around the natural features of the cave.

McDermott: How long is it predicted until some of those carvings and etchings become unreadable or unrecognizable?

Wood: When it comes to the degradation of the caves, it's a function of the depth of the engravings. But you could actually see some degradation as early as 10 or 15 years, from what I've seen.

McDermott: How did this project differ from other projects you've worked on?

Wood: We do a lot of buildings, bridges, roadways, geo-tech features -- based on my job, but the cave was unique because of its ornate nature. We had a challenge with the data set when it came down to the well area. Just because it was essentially an irregular spiral staircase, that tiny little area the cave took nearly half the scans of the entire project.



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