Image courtesy of the National Park Service

Exploring the stunning caves of the National Park Service in real-time 3D

Blase LaSala is a former park ranger turned government contractor for the National Park Service, traveling across the US to scan cave networks and produce real-time visual representations for research and tourism. Blase started his career by documenting caves manually, until he got his hands on a laser scanner and downloaded Unreal Engine. 
National Park Service cave technicians have an unusual job. Besides maintaining and preserving caves for public tours, they can be called upon to visit and catalog pristine, unexplored spaces deep underground.

For the first few years after Blase LaSala earned his degree in geoscience, he was a cave technician (also called a physical science technician) with the National Park Service (NPS), working to minimize human impact along public tour routes. Occasionally, he also got to explore and survey remote subterranean systems. “Basically, I was a cave janitor,” he laughs. “But then other times, I got to help map parts of caves that had never been seen by anyone. That part was definitely the best.”

One day, Blase got a hold of a laser scanner, and his career took off in an unexpected direction. “I loved playing Unreal Tournament when I was younger, and I spent a lot of time beta testing maps and mods that the community created,” he says. “When I saw the data that laser scanners could produce, I instantly wanted to see if I could convert it into a virtual environment.”
Image courtesy of Brooke Kubby
Blase is now the go-to person for 3D digital cave tours throughout the USA. Using a LiDAR scanner, photogrammetry, supercomputers, and Unreal Engine, he scans caves and produces videos and virtual reality experiences, giving both scientists and the curious public a comprehensive look at these breathtaking hidden worlds.

While many national parks already have virtual tours, these are largely composed of photos and videos with limited perspective. 3D virtual tours capture detail that can be viewed from many angles, and can give us a close-up look at intricate formations without the risk of damaging them. 

For the past year, Blase has been creating virtual experiences from miles of cave passages, making these natural wonders accessible at a time when so many NPS caves are closed to the public due to COVID-19 restrictions.

​​​​​​​Besides making cave tours available to the public, these interactive environments also serve the scientific community, enabling geoscientists to perform comprehensive research just from the visuals alone. As a bonus, those who would have difficulty entering a cave—due to physical limitations, or mental discomfort in closed spaces—can now enjoy educational and aesthetic benefits similar to those from a live visit, all from their computers.
Image courtesy of the National Park Service
Unretouched Unreal Engine representation of Lehman Caves.

Learning 3D: a tapioca cave

While Blase enjoyed all aspects of being a cave technician, his favorite part was exploration. As part of their work with the NPS, a small team of experienced cavers would follow a map to unknown territory, wriggling through tiny tubes and wading through water to reach the edge of a known cave.

“You have to really like crawling around in mud in the dark, which I do,” laughs Blase. “Some of the cave systems the National Park Service manages are over 100 miles long, and occasionally we’d have to camp there for multiple days. When you opened your eyes in the morning, it was just as dark as when your eyes were closed.”

The purpose of such trips was to inventory the passages and take measurements so a map could be created. The team took photos of items of interest—crystals, gypsum hairs, animal bones—and sketched the walls and features of the cave by hand.

While Blase was on these expeditions, he sometimes wondered if there might be a better way to record and share the data they were collecting, and to somehow combine his love of video games and cave exploration to provide a truer sense of what they’d found. “I thought, a map is okay, but what if there were a way to experience this virtually?” he says. “A three-dimensional representation would be useful for research and science.”
Image courtesy of the National Park Service
Image of Lehman Caves, straight from Unreal Engine.
Blase spent the winter of 2014 at Wind Cave National Park in South Dakota, and it was there that he got his hands on scanning equipment for the first time. The park had access to a Leica HDS scanner on loan from the nearby Oglala Lakota College, but had yet to make much use of the data.

“The GIS specialist at Wind Cave, Kevin Kovacs, gave me the opportunity to use the equipment,” says Blase. “He saw that I had a passion for it, and he let me run with it.”

Blase used Leica’s own Cyclone point cloud processing software, along with MESHLAB and CloudCompare, to convert the raw data from the scanner to 3D models in OBJ format.

“There were no textures, but I tossed it into Unreal Engine to see how it would go. It looked like a cave made of tapioca,” Blase observes, “but you could recognize where you were. I showed it as a proof of concept to people at Wind Cave, and everybody thought it was cool.”
The evolution of 3D cave visualization. Left to right: the first crude “tapioca” scans from Wind Cave in 2014, real-time grayscale environment created from scans at Timpanogos in 2019, and full-color real-time representation of Lehman Caves from scans and photos in 2020.

Combining education and a first project

Around the same time, the Timpanogos National Park Monument in Utah was looking for someone to document their caves using LiDAR. Blase, with his geoscience background, cave-mapping skills, and scanning experience, was a natural fit.

The job required Blase to take a Faro Focus LiDAR scanner on an early-winter hike up a steep trail that switchbacked up an avalanche chute, then enter frigid caves with humidity levels near 100%. Blase set upon the task with a healthy respect for the equipment in his care. “I carried that scanner like it was an infant,” he recalls. “After a day of scanning, we kept it next to a space heater so it wouldn’t get cold.”
Image courtesy of Brooke Kubby
The two weeks of scanning produced a point cloud comprised of 22 billion points that represents over a mile of passage, with a high enough resolution to see “soda straws”—cave formations with the same diameter as a pencil. At over a terabyte of data, the virtual environment was cumbersome to process and required specialized software to run. 

While the project was considered a success, Blase wanted to push the data into something that could better convey the thrill of exploration and the character of the caves. Ultimately, he paired the project with his educational endeavors—a graduate thesis at the University of Arizona—and in 2019 he simultaneously earned a master’s degree and provided Timpanogos Cave National Monument with a 3D digital tour of its three-cave system. Blase used the university’s supercomputing cluster to process the point cloud data with an open-source meshing algorithm by Misha Kazhdan. For his novel “end-to-end” workflow, Blase won the honor of Outstanding Graduate Student from the Mining and Geological Engineering department.

Blase credits Unreal Engine as being integral to this achievement. “I don’t have a computer science or 3D modeling background,” he states. “All I know how to do is convert terabytes of data into a format Unreal Engine can understand. Then it does everything else for me.”

Moving to realism with color

Following on the heels of this success, Blase formed a company devoted to scanning caves and producing 3D virtual tours. In early 2020, his company completed a series of tour videos for Lehman Caves in Nevada’s Great Basin National Park.

For the project, Blase used a combination of LiDAR and photogrammetry, representing a huge step forward in visual fidelity. While the Timpanogos 3D scene is monochrome, Blase was able to produce the Lehman Caves videos true to color with help from over 100,000 photos, giving the virtual visitor a much more realistic experience.
Image courtesy of the National Park Service
Image of Lehman Caves, straight from Unreal Engine.
In addition, the multi-terabyte model is sub-centimeter accurate over a mile of passage, making use of normal maps, global dynamic lighting, and LODs to run in real time. “You can see anything larger than a fingernail,” Blase says. “People recognize the formations and rooms they’ve seen before. We compared it with photos, and made sure it was a good representation.”

He adds that real-time technology has advanced so swiftly that his work is now approaching the limits of the scanner, not the software. “This is unprecedented,” Blase says. “I used to have to throw out most of the scanner data, because the software couldn’t handle it. With Unreal Engine, you don’t have to make those compromises.”

For interactive simulations, Blase made use of Unreal Engine’s VR and first-person templates. “It’s great to have the templates there, premade,” he says. Blase has produced VR experiences for Timpanogos, designed to be enjoyed on the premises—sadly, due to the pandemic, these experiences have not yet been made available to the public. But when he last tested them, Blase was delighted to find that these Unreal Engine projects ran at 90 fps on a GTX 1080 Ti graphics card with an Intel 6900K processor. “Just imagine how they’ll run on newer hardware,” Blase muses.

Blase appreciates that once the data is formatted correctly, Unreal Engine does most of the heavy lifting for him. “Between the templates, textures, and automatic LODs, it just works,” he says. “It’s terabytes of raw data, and Unreal Engine can ingest it and optimize everything automatically.”

Imagining the future of cave scanning

While scanning and real-time technology aren’t yet in wide use among geoscientists, Blase anticipates that they will become key tools to help them perform research and solve problems. “Being able to see and interact with the cave in three dimensions, you see things that you never thought you’d be able to see,” he says. “You can get right up close to a formation or a feature that might be out of reach in real life. You can come back as many times as you want without worrying about damaging any delicate formations.”
Image courtesy of the National Park Service
Image of Lehman Caves, straight from Unreal Engine.
While continuing to scan caves and produce media, Blase is now going for his PhD at the Northern Arizona University as a member of Dr. Teki Sankey’s Geoinformatics lab. Geoinformatics involves taking streams of data from remote sensing instruments, such as LiDAR scanners and multispectral and hyperspectral sensors, and leveraging them for statistical analysis, feature extrapolation, and visualization. Naturally, Blase has brought his newly acquired skills with him. “Unreal Engine could revolutionize how we visualize and work with these data sets,” he says.

As for Unreal Engine 5, Blase is excited about the prospect of using the new Nanite feature to optimize the multi-billion-polygon 3D models he works with on a regular basis. “I can’t wait to see how hard I can push it,” he says.

Blase proposes that once others realize how easy it is to create visualizations with Unreal Engine, it will be used more and more for science. “I’m not a specialist—I’m a former park ranger who likes to crawl around and get dirty,” Blase says. “If I can learn Unreal Engine, anyone can.”
Image courtesy of Brooke Kubby
Note: The views expressed here by Blase LaSala are his own, and do not necessarily represent the views of the National Park Service.

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