Have our Geo-Surveying Division found a solution to the age old problem of As-Builts?

The Geoslam Zeb Revo & Eoin Gorman in action

Anyone site based who has been around at the end of a project will understand how laborious it is to capture any ‘red-line’ changes to allow our BIM teams to update models and drawings prior to handover.

Introducing “Point Cloud Lite”, the use of a Handheld Laser Scanner for quick and inexpensive point clouds, the data from this can be used after construction by BIM to alter IFF Models (Issued For Fabrication) to an As-Built 3D Model, which are often required as part of contractual obligations.

Rob Hughes and his Geo-Survey Division have invested in a Geoslam Zeb Revo. This is a handheld instrument that allows surveyors to quickly measure installations with unrestricted mobility.

The benefits include:

Specifications:-

• Small, light-weight handheld laser scanner (only 1Kg)
• 40,000 points per/sec
• Accurate to +/- 10mm
• Produces 3D point clouds of built environment.
• Works best internally with a range of 30m.
• ‘scan as you walk’ instrument

Advantages for Data Collection:-

• Efficient means of data acquisition
• Data acquisition possible in hard to reach areas (no scaffold or other access required)
• Full coverage of mechanical and electrical services.
• Limited range but ideal for detail-dense internal environments.
• Can be coordinated with BIM model

Advantages for BIM:-

• Alternate method for Redlining As-builts.
• No need for initial paper based documentation of As-builts.
• BIM technicians obtain information from point cloud rather than 2D drawings
• Dense detail rather than single tape measurements.

A Standard Laser Scanner can record 1 Million Points Per Second, while the handheld scanner can record 40,000 Points Per Second, hence the handheld scanner provides a lower level of detail. It has been found that the detail provided by the handheld scanner is sufficient for BIM requirements.

Due to the savings above, interim scans can be carried out throughout construction, any clashes are picked up as the project progresses, eliminating issues that may occur thereafter.

As this method is adopted on all projects going forward we should start to see manhours normally spent on red lines being redirected to other activities at a critical time in the project schedule.