3D Laser Scanning White Paper

3D Laser Scanning

This article summarizes the applications and benefits of applying 3D laser scanning technologies to the design, construction and operation of facilities and infrastructure. We examine how these technologies work and how they deliver four main benefits: 1) cost reduction and schedule compression; 2) risk mitigation; 3) improved safety for capital project delivery and operations; and 4) how these benefits are realized and exploited by asset owner/operators, design and construction firms.

How does 3D laser scanning work? The capture of 3D laser scan data can be compared to that of taking a digital picture. The equipment used looks similar to common survey equipment and sits atop a tripod. It uses a laser to measure the distance to a point (pixel) on an object it can see in the environment. As it measures these objects it is recording the x,y,z coordinates. The scanners typically have the capability of recording approximately 1 million points per second at ranges up to 1,000 feet. Many scanners are also equipped with an HD camera. It will use the photos that it takes to map the color of each point/pixel so that it may be more visually interpreted. Since these laser scanners can only measure what they can see, the scanner must be repositioned to access line-of-sight. Current technology allows the scan to be "stitched" together through a registration process, or in some cases, may be real-time registration.

This creates a digital 3D environment that can be viewed as 360 panorama images or within a 3D CAD platform. Project teams and facility owners can then use this data to collaborate, draft, model, and measure as-built conditions without having to revisit the project site. In addition, accuracy is typically within ", which is drastically better than traditional methods.

Applications:

As-Built Documentation for Buildings, Infrastructure and Utilities Scan-to-BIM Historical Preservation Clash Detection 3D Visualization Panoramic Photo Documentation Mechanical Rooms Refineries and chemical process facilities Electrical sub-stations Manufacturing and Industrial facilities Water and Wastewater treatment facilities Forensics - Accurate Crime & Accident Scene Documentation

KEY BENEFITS

Cost Reduction and Schedule Compression: Laser scanning has proven to reduce total installed cost and has reduced contingencies for rework compared to traditional survey methods across a wide variety of projects. Achievement of these cost savings sometimes requires higher initial investment in 3D data capture solutions than traditional methods (total station, piano wire, spirit level, plumb bob and tape measure). Schedule compression of as much as 10% has been reported when 3D laser scanning has been utilized. Such savings are substantial compared to the cost of data capture and modeling in applications where downtime is a key concern.

Impact on Bidding Process: The increased availability of accurate as-built 3D geometry based on laser scanning relieves the need for high contingencies in contract documents and for change orders on a project. The business tactic of winning a contract with a low bid and expectation of change orders is less attractive in a bidding environment where the as-built documentation is both accurate and complete. Engineering/construction firms that have mastered 3D scanning work flows appear to have a significant competitive advantage. Winning bidders without rigorous dimensional control procedures may well be exposed to stiff losses. Some engineering/construction firms report that they use 3D scanning on almost every renovation project.

Enhanced Collaboration Among Project Stakeholders: The ability to communicate this data is enabled through several methods. 3D simulations, animations and walkthroughs aid both technical and non-technical personnel. When a facility owner provides the team with an accurate 3D model of the facility, they can reverse engineer it from all angles and design in a virtual environment around existing conditions. The project team is not then relying on their own individuals to take field measurements and pictures, translate those to a CAD environment, and communicate them to others. The 3D imagery that is captured should not be discounted. Users are provided access to the data via a website that allows them to navigate and measure the field conditions in a graphically rich environment. Now all users, including non-technical personnel, can review the same field conditions without having to be on-site. Engineers benefit from high-quality collision detection and fabricators are armed with intelligence to avoid mis-fittings.

Risk Mitigation: All industries experience projects where cost, schedule or safety has spiraled out of control due to incomplete or incorrect as-built documentation. Laser scanning workflows have proven beneficial for reducing project risk on projects, particularly where safety risk is high, site access is difficult or expensive and project schedules are sensitive. Reduce Time and Errors by:

reducing the number and types of manual measurement errors providing advanced interference and clash detection for new installations without the need for return site trips executing construction activities with fewer mismatches and design errors responding to schedule upsets and changed field conditions with more flexibility Improve Planning and Design by: improving processes by creating drawings and models where none previously existed analyzing engineering design plans, checking for clashes between existing conditions and new design elements and evaluating alternatives before project costs are committed designing without the need for large field tolerances (VIF) Improve Work Processes By: providing consistent as-built documentation for design specifications providing exact measurements for demolition and removal in existing facilities prefabricating components with little excess material and accurate fit-up visualizing as-is conditions for asset management, inspection, constructability and funding procurement efforts accelerating construction, decommissioning and modification processes accommodating scope changes more intelligently

Each pixel has an (x,y,z) coordinate to create a 3D Point Cloud

Safety and Regulatory Compliance: Laser scanning is increasingly used to comply with health, safety and environmental imperatives. Compared to manual data capture methods, laser scanning methods are almost always safer. The remote sensing ability of today's scanning systems and their rapid data capture means reduced job site exposure. Off site fabrication methods can also lead to a much safer work environment. Owners are subject to increasing governmental scrutiny and regulation which demand the creation and upkeep of, not only the as-built, but as-maintained condition of production assets. Laser scanning provides a platform that can manage all of the required data.

Why Isn't Everyone Doing This on Every Project? Some key reasons why the adoption has been slow:

Lack of awareness. The technology is still fairly young and there aren't many available on the market. It is still early in the adoption cycle.

Perceived cost. For some projects, traditional methods are more cost effective, however, the price point has been dramatically reduced in the last couple of years making it a very competitive and viable option.

Inertia of old ways. Changing work flows is often painful. To get full value for laser scanning, organizations often need to embrace 3D and abandon familiar 2D processes.

Integration challenges. In previous years, integration has been difficult with most CAD software and hardware has been expensive.

Summary 2013 was a year of convergence where both hardware and software matured to a point where 3D data capture was within grasp for most design and construction firms. Scanning equipment and services are falling in price and service providers are becoming more abundant. The enhanced productivity and cost savings have been proven over the past decade and now the technology is easily attainable, making it a compelling value proposition for today's projects.

About the Author: Greg A.M. Hale, PE CTO & Disruptor HALE Technology in Practice, LLC.

Greg has worked in the AECO industry for the last 15 years with a background in construction management, structural engineering, BIM management and technology consulting. He specializes in Autodesk Revit and Navisworks, laser scanning, and mobile technology and provides training, implementation strategies, product optimization, and best practice solutions. Greg is a certified professional in Revit Architecture and has spoken at many professional events. In addition, Greg is founder of HALE TiP, RocCity Revit User Group and has been a member of multiple NCS and NBIMS task teams. ghale@

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