The Royal Palace in Luang Prabang, Laos. Screencap from the Wheel of Green M.App online file

Digital Twine

Stephen Black


A series about Augmented Reality and digital twins.

Digital Twine 1: Yohann Ly and the Leica BLK2Go

This article aims to provide value to those in the fields of BIM, architecture, construction, building maintenance/repair, healthcare infrastructure, and factory/warehouse management best practices. Adventurous, non-technical readers are welcome as well!

The project discussed is of special interest to the author, as his AR journey began in Southeast Asia eight years ago.

Note: Although Yohann’s project does not yet have an immediate connection to AR, the BLK2go scanner is used extensively by many in the GeoPose-based AR community.

19.8922° N, 102.1356° E, May 7, 2023 Luang Prabang, Laos

A mural inside of a temple: a dozen young monks begging for alms at dawn in the streets of Luan Prabang. The monks’ saffron robes, shaved heads and bronze bowls dominate the composition, contrasting with the town’s graceful architecture and the surrounding mountains of green. It is just after 8AM,;the mural is alive with light.

The mural was painted in 1930 by , Alix de Fauntereau. One wonders how, that so long ago, this French woman found herself creating this Impressionistic masterpiece.

Imagine her standing on a scaffolding: looking very closely at her work, then stepping back and adding a brushstroke or two. (Something like this.) She holds her palette steady.


Now, outside, on the other side of that same wall, an IMU is doing the metaverse equivalent of “holding a palette steady”. An IMU, an Inertial Measurement Unit, is measuring and reporting acceleration, orientation, angular rates, and other gravitational forces. IMUs are found in smartphones, wearables, AR and VR, drones, gaming and robot applications. They aid with real-time motion detection, indoor navigation, gesture and activity recognition as well as optical image stabilization (OIS).

This IMU is in something that resembles a big black pill, a BLK2go. The BLK2go sends out, measures and records laser signals 420,000 times per second. It does this with what Leica calls GrandSLAM technology, a combination of LiDAR SLAM, visual SLAM, and an IMU.

The young man moving the BLK2Go around the temple is Yohann Ly. Yohann lives in Paris, where he is the supervisor and technical lead for Hexagon’s Safety, Infrastructure & Geospatial division in France. Yohann combined his love of bicycling with his technical background to create this, the Wheel of Green biking and scanning project. Updates from his journey are on M.App.

Yohann can speak Vietnamese; his father was born in Vietnam. But Laos is not Vietnam, of course, and when he asked one of the many guards for permission “to take photos”, he did so in English. He was afraid that the inability to speak Lao would result in no permission, or even being questioned in a room somewhere. When he was given an “OK”, his heart leapt with thankfulness. He immediately circled the temple, planning for the most efficient, most detail-filled scan possible. The biggest challenge was to avoid scanning people. Although he was the first to enter the temple grounds, Johann knew his perfect solitude could disappear suddenly.

The temple is absolutely gorgeous. A Laotian and Beaux Arts mix of surfaces, intricate details everywhere. Carved golden dragons, Italian marble steps and palm trees. Symbolic doorways and arching tiled roofs. Over the entrance is a sculpture of a three-headed elephant sheltered by a sacred white parasol. All of this beneath a bright blue sky. The Mekong and Nam Khan Rivers, both nearby but unseen, seem to bathe the place with a sense of calm.

At 6AM, when Yohann woke up, it was already 30C. The humidity laughed at him as he walked to the temple. His journey took place during the hottest season in Southeast Asia; later in the day it reached 40. To save weight and space, he had packed only one shirt and pair of pants.

Near the temple is a piece of the moon. The moon rock, gifted by the United States, is one of many presents that various countries gave to the Laotian government. There is also a collection of cars once owned by the Lao Royal Family. In the turmoil of the Vietnam War, the royalty were sent to re-education camps.

Yohann’s scan of the temple took eight minutes. He had no idea where and when he would later find a computer and wifi that could handle the size of the 3D file. This wasn’t a problem. Flexibility and freedom were the highlights of his trip, Yohann told me.

“Traveling by bicycle allowed me to be open to many possibilities. I wasn’t always sure where I would sleep. Being alone, it was less difficult to meet people. Asking for directions or food recommendations sometimes led to conversations that in turn led to shared meals, and even being invited to spend the night as a guest. It was amazing to have the opportunity to interact with people and gain an understanding of how they live life.”

Some will say that Yohann created a digital twin of the temple. However, true digital twins recognize that buildings are like living things- they are all different. A true digital twin is not just the exterior, but can include things like electricity layout and usage, water consumption and all kinds of real-time sensors and monitoring applications.

The person scanning should be aware of who will use the scan. Will it be used by OSHA, a legal team, real estate agencies or insurance companies? Government agencies? Health care providers? Interior designers or movie makers?

As reality capture technology continues to progress, new uses will appear.

Point cloud files are not just 3D digital artworks made of specks. Point clouds can be sliced. They can be used to generate things like floor plans, complete with site-specific annotations. If a building is scanned periodically, structural changes can be seen. The addition and removal of new pieces of equipment can be planned in an extremely short time. With the BLK2Go, 4K high resolution photos are possible and can be tagged for easy positioning.

It was amazing to have the opportunity to interact with people and gain an understanding of how they live life.”

With Wheel of Green, Yohann configured the M.App dashboard to share data about elevation, distance traveled and temperature. Widgets and templates made this easy.

More details here.

With the scan of the Royal Palace complete, Yohann walked back to his hostel, thinking of coffee, croissants and waterfalls. A large amount of data was generated during the Wheel of Green project. We can only imagine what it was like to walk through the morning chatter of Luang Prabang, looking at the mountains and thinking of the next remarkable location to scan.

Wheel of Green Instagram

“With a bike, it’s all about the journey.”

In researching this article, I traveled the world with the eyes of a scanner.(Am I becoming a “scannerologist”?)

The Netherlands (with its challenge of branchebrede meetinstructie!)

Marysville, Ohio

Little Rock Arkansas and Bologna, Italy

Fawcett City At the VIEW Conference of 2020, a fellow presenter mentioned that a digital twin of downtown Philadelphia was created for the Shazam movie. However, I can find no mention of this online.

About the author:

Stephen Black is an artist/producer and the spatial cinema artist of the OARC, the Open Augmented Reality Cloud. In 2015, After successful careers as a video producer (CNN, Cartoon Network, Fuji TV), photographer and writer, he focused upon the potential of AR. He is the co-creator of Bubiko Foodtour a pioneering little chef who cooks up excitement in all things web3. Bubiko: First Flight, a short film, is considered to be the equivalent of the world’s first website as it was the first public project on the spatial web.

July marks the debut of Butterfly Tree, an AR project Stephen executive produced with Novaby for the Strong National Museum of Play. Stephen is currently planning another history-making GeoPose AR project in Fredrikstad, Norway. He is available for AR art commissions, consultations and commercial productions. Bubiko will soon be appearing on the App store.