Remote Inspections of Under-Construction Buildings in the Metaverse

Shimizu Corporation (President: Kazuyuki Inoue) recently developed a metaverse inspection system capable of performing various remote inspections of buildings inside a virtual space with realistic replications of under-construction buildings with the assistance of TSUMIKISEISAKU under the direction of The Building Center of Japan (President: Kimihiro Hashimoto; “BCJ”). The system consists of a metaverse, which combines the 3D scan model of the building with design BIM (3D) data, and xR Checker, a tool for checking the consistency between the two. In the future, Shimizu intends to open this system to the public and contribute to streamlining building construction and production in Japan.

Every year, after building permits are received, nearly 600,000 buildings nationwide undergo various inspections repeatedly from the start to completion of construction to verify conformity with the drawings the building permits were based on. Construction supervision by designers and intermediate and final inspections by chief building inspectors and others from the government are typical examples of this. In many cases, multiple persons in charge visit the site, drawings in hand, to perform visual inspections and conformity checks using simple measuring instruments. They also review progress photos and various inspection reports. However, a vast amount of time is spent traveling for inspections, with travel time for completion inspections alone exceeding 1 million hours nationwide.

Shimizu has been working on building permit applications and various inspections using BIM data to improve the efficiency of building construction and production since June 2019. Shimizu has already developed a system that uses augmented reality (AR) technology to perform various remote inspections via a tablet screen, and this system has been well received by the BCJ. The challenge was to increase the sense of presence by eliminating constraints of the field of view. Metaverse inspection solves issues such as these in one fell swoop and has the potential to serve as a touchstone for accelerating the widespread adoption of remote inspections.

The metaverse that makes up this system combines BIM (3D) data on buildings that have received permits in the cloud with 3D point cloud data on scans of the space of under-construction buildings. By wearing VR goggles, the inspector can enter the metaverse as an avatar, opening up a realistic field of view without any constraints. Operating the controller, the inspector can instantly move the avatar to any location in or around the building and perform various inspections from any viewpoint, even those not available in reality, such as a bird’s eye view. Inside the virtual space, it is also possible to have voice conversations with relevant parties from other locations who are present as avatars and check documents such as process photos and various inspection reports downloaded from the cloud. Moreover, the xR Checker functionality allows instant automatic measurement of the consistency between BIM data and point cloud data, providing a color-coded display of the differences that exceed the set tolerance.

These functions allow for various inspections of under-construction buildings regardless of location, contributing to more efficient building construction and production while streamlining and enhancing inspections. The system has already been verified using actual buildings. Although some areas for improvement have been identified, the BCJ says that it is suitable for practical use.

The Ministry of Land, Infrastructure, Transport and Tourism issued a notice dated May 9, 2022 to the director-general of the architectural administration of each prefecture entitled, “Remote Implementation of On-site Completion Inspections Using Digital Technology Based on the Building Standards Act.” Based on that notice, it is expected that in addition to building permit applications, the use of BIM will rapidly spread in inspections associated with building permits and the processes of construction supervision. As a Digital General Contractor, Shimizu intends to contribute to the efficiency of building construction and production throughout Japan by utilizing BIM data.