Projects

Case study: New Taipei City – Bentley software saves 80% of 3D modelling costs

20 February 2019 | By BIM+ staff

  • Client: New Taipei City
  • Lead Contractor: RealWorld Engineering Consultants
  • BIM Tools: ContextCapture

RealWorld Engineering Consultants was commissioned to survey and produce a 3D reality model of a 1,000 ha area of New Taipei City.

New Taipei City is a special municipality in Taipei and the most populous city in Taiwan. The city includes a stretch of the island’s coastline and surrounds the Taipei Basin. Known as Taipei County before its upgrade in 2010, the city surrounds Taipei and is the second largest special municipality in the area.

The region includes at least 4,000 houses and multiple buildings. The project was completed at the end of August 2017, and the mesh will be used for follow-up urban design planning and review of the city.

RealWorld was responsible for the entirety of the $265,000 project, from aerial photos and oblique image acquisition to 3D model building at the later stages of the project. The company was also in charge of delivering the final 3D GIS (geographic information systems) platform analysis applications.

The project produced high-precision, high-resolution, 3D urban models that will later be used as the basic drawings for the follow-up 3D GIS platform planning analysis. These models will also help build 1,000 ha of 3D models and provide a 3D GIS platform for relevant employees to conduct analyses.

The area that needed to be documented was sizable, which was RealWorld’s main challenge. Traditional methods would have been arduous and time-consuming with so many buildings, but the project team met its deadline using ContextCapture, Bentley’s 3D reality modeling technology.

The project team created the 3D GIS models of the area in New Taipei City with ContextCapture. Users gathered geographic information of the area using unmanned aerial vehicles to capture photo imagery and point clouds using a wide variety of cameras and then input the data into ContextCapture. Then, RealWorld used ContextCapture to natively support several types of positioning data to produce accurate georeferenced 3D models in a full range of GIS formats.

“ContextCapture software can quickly build high-precision, high-resolution 3D models and completed 1,000 hectares of 3D model building within a month,” said Seager Peng, aerial survey manager at RealWorld Engineering Consultants.

Collaborating effectively

These models improved collaboration among the multidiscipline team and project stakeholders. ContextCapture generated many common 3D GIS file formats, such as OBJ, digital asset exchange (DAE), KML (formerly keyhole markup language), Cesium, and other formats often used.

These formats are popular throughout the world, making it simple to transfer data in different formats to other design units. The project team could easily share models with each other, no matter the type of 3D GIS platform format. Also, ContextCapture allowed for easy measurement and analysis of model data. The team could save time getting accurate answers by performing precise measurements of distances, volumes, and surface areas directly in the model.

ContextCapture also helped create better 3D model results, which RealWorld then shared with its project stakeholders. When using traditional imaging methods, such as airborne photography and oblique images, to build models, there are often portions of the model that are not visible.

This situation is common when there are places where aerial surveys are obstructed. However, ContextCapture can be combined with ground-based light detection and ranging (LiDAR) and aerial photography to produce high-precision models that avoid those holes.

The team also used ContextCapture’s high-fidelity imaging capabilities to support precision mapping and engineering, ensuring that all models were visibly accurate for the team’s project stakeholders.

Doing more in less time

The project team could use one-tenth of the labor usually required for the manual geometric method to build 3D models. This is impressive because the target area of the 3D models was more than 10 times larger than the target area used with the traditional method, and it was completed during the same timeframe. Compared to traditional methods, the project team saved 90% of the total project time.

The ability to create models with both aerial photographs and point clouds helped improve model precision of narrow lanes under the shelters in aerial surveys. The use of ground-based LiDAR with ContextCapture increased model accuracy by 20-30%. Additionally, the cost of constructing the 3D model decreased by nearly 80% using ContextCapture.

Planning for the future

New Taipei City plans to continue developing new infrastructure as well as maintain its existing structures. The 3D GIS models created by RealWorld will make it easier for future users to use this information.

When others view the model skyline or make urban planning analyses, such as for sunlight shadow, they won’t just review them with 2D maps and imagine the rest. Instead, they will conduct urban design analyses with real 3D maps and models using the application’s analysis capabilities.

This practice will help design new urban spaces in New Taipei City and sharing the information with others.