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The Skinny on Laser Scanning: How It Works, When to Use It, and Why You Need It

In the Architecture, Engineering & Construction (AEC) industry, 3D laser scanning is becoming the go-to tool for contractors looking to reduce risk and increase collaboration. Laser scanning provides a fast and accurate way to collect large amounts of site measurement data which can be used in both the design and construction processes. 

The benefits of scanning are clear. In addition to making data collection easier and more precise, scanning helps you identify clashes and catch other discrepancies between the design and actual as-built conditions before they turn into bigger problems later. As a result, you’re able to reduce rework and change orders, avoid budget overruns, and keep projects on schedule.

The use of 3D laser scanning is helping the industry to address its long-standing productivity problems. Scanning not only makes your construction workflows more accurate and efficient, it can also improve your overall productivity. Advancements in today’s scanners allow AEC professionals to collect the data they need, when they need it, right in the field—with no specialized training required. This allows you to get more done with your current teams and resources, instead of having to rely on outsourced experts or trained technicians to scan for you. 

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3D scanning into your existing BIM process

To see how 3D laser scanning can help you address the unique productivity concerns you may have within your own organization, it’s helpful to first understand the basics of 3D laser scanning. Let’s take a look at the typical workflow and some common challenges scanning can solve.

3-Step Scanning Workflow

Understanding the typical scanning workflow helps you connect the dots between the data you gather in the field and how it’s transformed into detailed models back in the office.

Step 1: Scan the area

The first step in the scanning workflow is to place a 3D laser scanning instrument in the field to scan your designated area. The instrument uses a laser to collect measurements of individual points. The technology and measurements are similar to those of a robotic total station where points are recorded with an X, Y, and Z value. The instrument rotates 360° horizontally, collecting as many as a million measurements a second in a 300° vertical window. These measurements are called points, and together they form a point cloud. 

In typical applications, you can make multiple scans by placing the instrument in different locations so that measurement data is collected from various angles. Making multiple scans increases the accuracy of the data. 

Step 2: Register your data

Once you’ve taken all measurements of the area, the next step in the workflow is to register the data. During the scanning process, you typically place two types of targets in the area you’re scanning, either freestanding spheres or checkerboard targets attached to a surface. Using a desktop software application for registration, these targets create a point of reference so individual scans can be aligned to form a composite point cloud. 

The latest 3D scanners are capable of automating the process of registering individual scans into a composite point cloud while still on the project site. You’re able to review scans in the field on a tablet, integrate panoramic images, add field notes, and validate your progress, giving you greater confidence in the coverage and accuracy of your scans. Some scanners even provide the ability to export a fully registered and photo-colorized point cloud—while still in the field—that’s immediately ready for detailing and use in other applications.

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Step 3: Detail your data

The last step in the scanning workflow is to detail the registered 3D point cloud data. Using modeling software, you can isolate individual elements of the point cloud data and model 3D objects from the information. You can effectively create an entire model using the registered data.  

The 3D representation can then be used to detail and understand how new elements—such as walls or windows, mechanical equipment, or ductwork, for example—will connect to existing site conditions. The 3D model also allows you to discover any discrepancies between the design and existing conditions and make necessary adjustments before the build begins. 

How 3D Scanning Helps Contractors Increase Accuracy and Productivity

Whether you’re working on a renovation or a new build, scanning helps solve some of the most common and costly challenges you may face.

Missing or inadequate documentation

Renovations of old buildings, adaptive reuse conversions, and other redevelopment projects require current as-built drawings and documentation. But this level of information often doesn’t exist. Even if the original plans are available, they may not accurately represent actual as-built conditions. You could produce as-builts by taking manual measurements of the space. But this type of effort is both time-consuming and prone to human error. 

How scanning solves it: 3D scanning allows you to quickly and accurately collect all the measurement data you need of the current as-built conditions for any renovation or redevelopment project. You can then use the point cloud data to create a model and assist with the design phase. 

Conflicts between the design and existing conditions

Coordinating the work of architects and designers with structural, MEP, and other construction teams is often difficult. When it’s time to build, there can be conflicts between the design and actual site conditions that slow teams down, increase the risk of miscommunication and errors, and create prefabrication and installation problems that could lead to rework. Once the project is complete, ongoing facility management and maintenance can also be compromised when the design on file conflicts with the actual as-built results. 

How scanning solves it: With 3D scanning, you can overlay your scanned point cloud model with the design model and perform a comparison between the two so project teams can check for conflicts between existing and new conditions and update the model to the actual built conditions. This can help identify clashes early on, as well as ensure that prefab is accurately built and installed. You can also use 3D scans to create accurate documentation of installed systems, then provide this information to building owners as either point cloud data or 3D modeled objects which they can then use for ongoing facilities management.

Inefficient workflows and inaccurate results

The structural phase of construction, including steel and concrete work, is critical to the success of the rest of the project. But many structural workflows are inherently time-consuming, especially if mistakes are made. For example, pouring concrete slabs and panels correctly requires a lengthy process to schedule, complete, and test/verify. If problems are found after the pour—whether with floor flatness, incorrect locations of elements, or missing elements—it takes even more time to tear out the work, re-pour or re-level slabs or panels, or re-measure and re-set elements in the concrete. 

How scanning solves it: 3D scanning boosts both your efficiency and accuracy since you can check your scan data in real time against the layout or models. If you find discrepancies or inaccuracies, you can quickly communicate about and resolve them upfront, avoiding the risk of mistakes that result in schedule overruns, not to mention wasted materials and blown budgets.

Use 3D Scanning to Save Time and Money

3D laser scanners are becoming critical tools for construction companies. The latest advancements in 3D scanning technology are also making them more accessible and easy to use. A wide range of AEC professionals can now use self-calibrating 3D laser scanners with in-field registration to gather the scan data they need when they need it—with no specialized training required.   

When you put 3D laser scanners directly into the hands of those employees who need the information most, you’re able to improve productivity, stay on budget, and maintain schedules. Integrating scanning into your BIM processes connects your office to the field, driving even greater efficiency and faster decision making. Armed with complete and accurate as-built data, your teams are able to more easily identify and avoid conflicts between design and build, saving you from costly rework.

To learn more about incorporating 3D laser scanning into BIM and other workflows, get the guide.

About the Author

David Burczyk is the Segment Manager for the 3D Capture Portfolio with Trimble Buildings. With over twenty years of AEC industry experience promoting technology and collaboration among design and construction teams, David brings a comprehensive understanding of Building Information Models (BIM) and Virtual Design and Construction (VDC) processes. Through the use of 3D capture and positioning technology, David is focused on the development and implementation of tailored solutions to advance the field productivity of AEC contractors, architects, and engineers.

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