Yungang Grottoes 3D Printing Technology Offers Glimpse of Green Civilization

A viewer looks at a 3D replica of Cave No. 6 at Yungang Grottoes. Photo: CI

Buddhist statues at Yungang Grottoes Photo: VCG A viewer looks at a 3D replica of Cave No. 6 at Yungang Grottoes.  Photo: CI

Buddhist statues at Yungang Grottoes Photo: VCG

Editor’s note:

Carriers of a nation’s genes and spirit, cultural relics and heritages are irreplaceable resources for a flourishing civilization. A large number of Chinese relics have become more popular over the past 10 years and have made people around the world know more about Chinese culture. The Global Times will feature a number of these “star” artifacts in this series, bringing to life cultural relics stored in museums, heirlooms on display across the vast land, and texts written in ancient books.

As Chinese President Xi Jinping said, Chinese civilization, together with the colorful civilizations of other countries, should provide humanity with proper spiritual direction and strong spiritual impetus.

The Yungang Grottoes were created by the order of an emperor of the Northern Wei Dynasty (386-534) to appease ethnic strife through the spread of Buddhism. They have hosted dignitaries from more than 20 countries over the past decades.

In 2020, a digital exhibition centered on the Yungang Grottoes, a treasure trove of Buddhist art in northern China, became a sensation among art lovers in Shanghai. The exhibition featured more than 100 relics from the caves alongside works by contemporary artists inspired by the site. The most eye-catching exhibit was a 1-to-1 scale 3D-printed replica that exactly replicated the original appearance of one of the caves located over 1,000 miles away.

“After the Shanghai stop, visiting the expo was suspended due to COVID-19,” Ning Bo, head of the 3D printing technology team at Yungang Grottoes, told the Global Times.

“But this is all temporary. In the coming months, we plan to visit Jiangsu Province. Then we will continue our tour of Italy, Japan and other countries in the future.”

Made up of eco-friendly detachable blocks, the model faces a long international ship journey in eight large containers – no easy task given the impact of the pandemic.

“And that’s in addition to the transnational curatorial and joint planning aspects of the exhibit,” Ning added.

Despite more than 1,000 years of weathering, this light of human civilization is even more dazzling in the 21st century. Behind this lie the efforts of academics and the most advanced conservation techniques.

bumpy road

Conservation of the site has had its ups and downs due to the frequent wars and rapid industrial development that China experienced during the second half of the 20th century. It was listed as a UNESCO World Heritage Site in 2001.

In 1973, before nearly 200 reporters from 24 countries, then Chinese Premier Zhou Enlai announced the country’s determination to protect and renovate the Yungang Grottoes while in Datong, Shanxi province, to meet the then French President, Georges Pompidou.

From 1974 to 1976, caves No. 5 to No. 20 were repaired and reinforced and a number of sculptures were saved from the brink of collapse.

However, a major problem was a highway that crossed the desert in front of Yungang Grottoes.

According to the staff of the Yungang Caves Research Academy, about 16,000 coal vehicles pass through every day. The coal dust that was scattered on the Buddha statues turned acidic in the rain, accelerating the weathering of the long-standing statues at the site.

In the late 1990s, the dedicated coal highway was relocated and coal trucks were banned from passing near the site. The original highway has been transformed into a special line to accommodate tourists, while the local government has also moved residents living near the caves to the outskirts of the site.

Virtual restoration

Considering the great significance of Yungang Caves in the history of human civilization, how to preserve this treasure and present it to the outside world have become major questions for scholars.

For a solution, staff at the Yungang Caves Research Academy turned their attention to digitization.

In 2014, the creation of the Yungang Digital Center propelled the site into the “digital age”.

The research team digitized the data they had collected after spending years in the caves, allowing them to reproduce three caves (Nos. 3, 12 and 18 to date) by 3D printing.

Among them, the team conducted high-fidelity 3D digital data collection inside Cave No. 12, known for its precious Western and Eastern musical instruments.

The team used a degradable and environmentally friendly polylactic acid resin to print, adding a layer of rock paint on the outside to simulate the texture of cave walls, then another layer of weatherproof paint. also fire.

“You can imagine that the whole complex is a Lego-like model, with each Lego-like block over two square meters. We used eight containers to put it together,” Ning explained.

Besides presentation, Ning said the value of current 3D printing technology is vast, especially when it comes to scientific research and preservation efforts.

For example, 3D laser scanning technology is used to monitor cave weathering.

“We are like doctors, and the precious carvings on the surface of the caves are the patients. We work hard to treat them using physical and digital therapies that complement each other,” Ning added.