When J-Tech Design Ltd. of Ingersoll, Ont. looked to invest in new technology at the turn of the millennium, the choice came down to 3-D laser scanning or 3-D printing. Jonathan Paterson, now project manager at J-Tech Laser Scan, says they made the right decision.
The company specializes in 3-D laser scanning of intricate construction projects ranging from wastewater treatment plants and fabrication facilities to stadiums and heritage structures.
Laser scanning equipment has become lighter, faster and more robust, but the concept has never changed — to provide a digital representation of buildings, features and fixed equipment to ensure construction projects proceed without a hitch.
What’s really helped 3-D laser scanning to catch on is the ability of software used in construction to display "point cloud," the digital product delivered to the client.
"In 2001, the only way to convert point cloud to something visual involved using a manual method to produce basic shapes," says Paterson. "Today we can take point cloud information and see it visually in CAD format, Revit or whatever software the client is using."
J-Tech has adopted Leica scanners as the best technology for its clients.
"Some scanners are best at close range, while others scan distant points with precision," he says. "The best technology for the job, is the technology that specializes in delivering what you do."
In a typical assignment, J-Tech might be requested to scan the interior of a complex production facility, to ensure that new equipment will fit exactly into the space available — rather than require construction crews to make extensive alterations later.
J-Tech was called in to laser scan the Frank Gehry spiral staircase at the Art Gallery of Ontario on site, immediately following delivery.
"EllisDon wanted an as-built so they could be assured that the staircase would fit smoothly into the plan, even after the complex scalloped glazing was installed," says Paterson.
3-D scanning is also a gift that can keep on giving. Clients often ask J-Tech to resurrect older point cloud data files to tease out new details years after a scan was performed.
While some larger contractors have incorporated in-house 3-D laser scanning, Paterson notes that it isn’t a specialty a contractor should take on casually. The equipment is expensive, software is complex and thorough training is required. Unlike traditional survey equipment, even the optimal placement of the scanner requires expertise.
A laser scan can be completed in as little as 20 minutes or as long as an entire day. Counterintuitively, the longer the process takes, the more likely that error is introduced into the scan, so shorter is often better. Scans can also be most economically produced by scaling them to the tolerance range requested — the "error budget" usually expressed in millimetres.
"We’ve seen results of scanning where somebody unprepared produced a scan in which every feature four inches or smaller was omitted," he says. "We call that small bore interference, but in practical terms, when the new equipment arrived, it didn’t fit."
J-Tech crews have travelled to Canada’s north, Alberta, Trinidad and Qatar. However, one of Paterson’s favourite projects took place in Sarnia and involved long-time client Shell Canada.
"George Vero, a project manager at Shell was one of our early champions," says Paterson. "We credit him for coining a term that we still use, Virtual Field Fit-up. We’d worked with him in 2003 and he told us he would come out of retirement to work with us when their cat cracker (the equipment required to transform crude oil into gasoline and other products) needed to be refurbished. True to his word, that happened in 2011."
J-Tech worked for about five weeks, performing on-site scans, many on the interior of the vessel, to help determine why efficiency had dropped.
"Using our measurements, they began to make a case for improvements as they tore that cat cracker to its knees," says Paterson. "That was the first time we had really supported live construction and we were involved in every phase of dimensional control for every component that was either modified or enlarged.
"At the end of the project, they had completed work seven days ahead of schedule and they had redeemed tens of millions of dollars in anticipated lost production. We don’t believe that just anyone armed with a 3-D laser scanner could have achieved those results."
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