Reality Capture

3D Scanning Is Flying High

1 Jun, 2011 By: Susan Smith

Cadalyst Labs Report: Faster, more accurate, more affordable technologies are propelling reverse engineering and other applications to the forefront of design.

Editor's Note: This article was originally published in the Winter/Spring 2011 issue of Cadalyst magazine.

3D laser scanning continues to take the CAD world by storm with its ability to create a digital representation of an existing structure or product. Also referred to as reverse engineering, the process uses scanning hardware to collect millions of points in space that represent an object's surface. That collection of data, called a point cloud, can be translated using specialized software to prepare it for use in a CAD application, where it becomes the basis for design updates or retrofits.

According to Tom Charron, vice-president of global marketing for Rapidform, "The challenge is less about data collection than it is about how to make it useful for your needs. This is where reverse engineering comes in, and the latest methods involve making solid models that are parametric and history-based, so they're easily editable."

As technologies rapidly improve and become increasingly affordable, applications of 3D scanning are expanding for civil engineering, AEC, and manufacturing. Regardless of your industry, and whether you purchase your own hardware and software or hire a service bureau to do the work, now is the time to take a serious look at how 3D scanning could jump-start your design process.

Technology Advancements

Several developments have converged to accelerate 3D scanning adoption. Hardware and software are becoming more efficient, prices are dropping, and the process of converting point clouds to CAD data is getting easier.

Joe Croser, vice-president of products at Pointools, explained, "The speed the scanner can measure points enables users to capture more points in the same time — getting higher-quality and more accurate data. Or it enables them to do more scans within a time period, thereby enabling them to lower scanning costs from being on-site."

Marc Soucy, president of InnovMetric Software, said hardware companies have nearly completed the release of 64-bit drivers, making it possible to perform 3D scanning processes on 64-bit computing platforms, which provides unlimited memory for very large digitizing projects.

A huge determining factor in the growth of 3D laser scanning is plummeting hardware prices this past year. One example is FARO's Focus3D scanner, which is approximately 60% less expensive than the company's previously available models. "The really high cost of scanners kept many people out of the market," said Croser. With hardware prices now in the range of $3,000 to $60,000, even small- and mid-sized firms are getting into the 3D scanning game.

The scanning workflow typically has involved two to five pieces of software ranging in price from $3,000 to $30,000 each — but the latest software is changing that.

"Customers can now get their hands on software that enables them to directly reuse that point cloud model inside their preferred software, rather than having to buy specialized software and convert the point cloud into geometry to be able to take that geometry into their apps," said Croser. In Pointools' licensing deal with Bentley Systems, customers can reuse the same native Pointools POD format in all Pointools products. Pointools POD Creator can generate multiple files in a single import operation inside any Bentley application. "That eliminates the need to translate because you don't have to move it from one proprietary file format to another in order to use it in different application environments," Croser said.

IMAGINiT's Scan-to-BIM software allows users to go from the original scanned data directly into an Autodesk Revit model. "It is no longer a long convoluted path," said Beau Turner, director of business developement at IMAGINiT Technologies. "Being able to … reduce the types of software and number of software pieces you need is huge." By removing the need for that software, you reduce the bottom line, and the workflow path becomes more streamlined and invites fewer errors.

As speed goes up and price comes down, the demand rises for 3D point cloud models, creating a true shift in consciousness among customers old and new.

This 3D point cloud model of a U.S. Ford automotive plant comprises approximately 4.5 billion points and was captured using a FARO Photon 120 scanner. Automotive production lines need to be changed every time the type of car being manufactured changes. Pointools' Joe Croser explained, "Ford has completely transformed its workflows so they can now scan an entire production line in a day to create a full photorealistic virtual model as a point cloud with full color and texture. They can then use Pointools to group pieces of a point cloud and move those grouped pieces around, quickly acquiring a piece of information without doing any postprocessing or additional modeling."

3D Scanning for CAD

The applications of 3D scanning for CAD are varied, but typically fall into retrofitting, archiving, and inspection categories.

Civil engineering. Ten years ago, 3D laser scanning began to gain traction in the civil engineering world. The 3D laser scanning setup — with a tripod and camera hardware — is an extension of traditional surveying. Long-range scanners are typically used for civil engineering. Use has grown steadily, albeit a bit slowly, as is true of many technologies in the field.

3D laser scanning accurately captures large sets of 3D coordinates; for example, it can detect pavement distresses, such as potholes and large-area utility patches. With 3D laser scanning, civil engineers get a higher level of accuracy by capturing all data at once, instead of one point at a time. "They can focus on forms and how things flow and the landscape, rather than capturing a lot of geometry," said Turner.

If civil engineers want to find out how many cubic yards of earth are in a hill they can gather a surface topography with a long-range scanner to make calculations very quickly.

Building. In the past two years, the use of 3D laser scanning in architecture and construction has grown dramatically during the down economy as owners have opted for building retrofits and remodels over new construction, leading to the need to capture as-built data as a starting point for design modifications. Additionally, it is estimated that 60% of U.S. building in the next 20 years will be based on existing construction, reliant on old 2D drawings or no existing data at all. Finally, 3D scanning for AEC got another big push when the U.S. General Services Administration (GSA) issued a $60 million contract to integrate a system that would allow the agency to use scan data in building information models. The opportunity to capture as-built data for reuse is one that AEC firms can't ignore.

High-definition laser scanners are used by civil engineers to capture accurate site details, as shown here. Image courtesy of IMAGINiT Technologies.

Retrofitting applications in AEC are numerous, from scanning the simple but outdated facade of a building to scanning a complex section of a power plant or chemical refinery, but all allow designers to make additions or modifications quickly and accurately. Some agencies are using 3D scanning for archival purposes — that is, capturing as-built data for a historical, religious, or other culturally significant structures to create a permanent digital record.

Building data has its own complexities. Scanners must be able to get into places that aren't readily visible — for example, under ceiling tiles. Architecture projects typically use phase-shift or pulse-based time-of-flight digitizers.

A high-definition color laser scan captures details of a facility's mechanical room. The black circle is the scanning base. Image courtesy of IMAGINiT Technologies.

Manufacturing. In manufacturing, 3D scanning is used in archiving, reverse engineering, and inspection project workflows. It typically involves 3D laser scanners (on arms or coordinate measuring machines, tracked optically or by laser), fringe projection digitizers (white light), or x-ray digitizers.

When archiving, manufacturing organizations that have tooling or parts that predate their digital design files would scan the object, convert the scan data to a useful format (surfaces, CAD data, etc.), and store the data or reproduce the physical object using traditional or additive fabrication methods.

Reverse engineering is used to create a new object from scan data. Automotive aftermarket parts are a classic reverse-engineering application. Sometimes a manufacturer wants to create a product designed to attach to an existing automobile. Often, scanning the automobile is the fastest way to create digital versions of the relevant surfaces. The workflow involves capturing scan data, converting it to surfaces, and using CAD software to create a model of the new product.

IntelliLaser from AVEVA lets process plant owners digitally navigate through their physical plant assets via the web.

Inspection applications involve capturing a shape with a scanner so the shape can be analyzed and compared with CAD data or previously captured scans. Charron at Rapidform explained that the comparison data can detect manufacturing errors that can result in product defects.

In terms of retrofitting, manufacturers often try to make a new tool from an injection mold that was manufactured before the company used CAD. If a tool has worn out and must be replaced, users can scan the old part, transfer the data to CAD, and then produce a replacement part.

The aerospace and automotive industries are the biggest users of 3D laser scanning. Scott Harmon, vice-president of business development with Z Corp., said, "These are very large industries with significant resources invested in product design and manufacturing. These industries have extremely tight product requirements and demanding product-launch schedules. Using scanning in the design process and quality control helps them get [products] to market faster and ensures that manufacturing quality remains high."

Soucy at InnovMetric said 3D digitizing is used routinely throughout automotive engineering to accelerate the development of stamping and assembly tools; virtually assemble car components to detect clashes, design shims, etc.; and diagnose and solve manufacturing problems before production. As a result, he noted, new car models roll out faster, saving tens of millions of dollars on each release.

Click here to read the "Scanning Hardware" sidebar.

Reverse Engineering: How It Works

"The most important thing beyond the scanner itself is post-processing software that can make use of dense point clouds or meshes [collected by the scanner]," said Charron at Rapidform. "Most CAD, CAM [computer-aided manufacturing], BIM [building information modeling], and other engineering software cannot make use of the raw scan data. On the manufacturing side, products like Rapidform, PolyWorks, and Geomagic can prepare data for use in CAD or verify parts against CAD models. Converting point clouds to polygons, healing scan data, and converting scan data to CAD data are all processes that peripheral software packages can handle."

In a collection of 3D points, each point is assigned an x, y, z coordinate, but the millions of collected points are not organized. The information needs to be in a more useful format, said Larry Carlberg, service bureau manager for GKS Global Services, a subsidiary of Laser Design. "The reverse engineering packages we have adopted and resell with our equipment enable an engineer to convert this point information to a format usable on his software."

GKS first connects all these points into a mesh that becomes a CAD surface that can be translated to a definable contour understandable by CAD — an algorithm that will be triangulated. This mesh also can be used for rapid prototyping processes such as stereolithography.

Each tool has a strength another lacks, which is why GKS resells numerous packages. "Geomagic might work better for an artist working with organic shapes, where Rapidform would give better strength for a model," Soucy said.

Software products such as Pointools address the issue of getting point clouds into BIM format, as does IMAGINiT's Scan-to-BIM application for Autodesk Revit. Users can import the point cloud, visualize it within the design environment and then interact with it. In this situation, users work inside Revit but also have the extra geometry recognition tools necessary to work with point clouds.

In discussing scanning for AutoCAD-based tools, IMAGINiT's Turner said, "Once we get [the data], we bring it all together into one unified point cloud, which you then register through a state plane or a georeferenced location. Then you can push it out to another file format and that's where AutoCAD-based tools can come in. Inside pure AutoCAD and the AutoCAD vertical environment, they have an engine that allows you to bring in point clouds — this only exists in the AutoCAD platform."

Autodesk's point cloud capability for AutoCAD Civil 3D and other products registers the data, meaning the scans are ori-ented and georeferenced. To capture the data, a scanner must be set up at several locations around a building. A scanner is line-of-sight equipment — it can capture only what it sees.

Kubit USA's PointCloud Pro runs on any scanning hardware and captures point clouds of existing conditions. Programs enable users to transfer data accurately and efficiently from various measuring devices or sensors into AutoCAD.

Geomagic's Studio software transforms 3D scan data and polygon meshes into accurate 3D digital models for reverse engineering, product design, rapid prototyping, and analysis and directly integrates with all mechanical CAD packages.

AVEVA's new IntelliLaser, an extension to the AVEVA NET information management system, adds intelligence to laser scan data, allowing process plant owners to digitally navigate through their physical plant assets via the web.

Pointools offers a plug-in for SketchUp as well as a plug-in for AutoCAD and several AutoCAD-based AEC products. "The SketchUp plug-in gives users other options for working inside a host application with the same point cloud data," said Croser.

"That's big from a 3D city modeling perspective. Now that people are realizing the speed you can model with it, they are using it for city modeling. As a result, people want greater context for their designs." Croser added that Pointools software doesn't rely on processing power to handle a lot of points because it has a very compressed file format that uses the company's own graphics engine to display.

Future of 3D Laser Scanning

The economy, affordability, and ease of use of 3D laser scanning make it attractive to an increasingly broad range of users. The need to obtain accurate measurements of as-built structures; to retrofit roads and bridges; and to capture data for product redesigns, inspections, and other applications — while hardware and software technologies continue to become more refined and affordable — will drive even greater adoption of 3D laser scanning in the coming years.

Considering a 3D Laser Scanner?
If you are considering adding 3D laser scanning to your workflow, answer these questions to help determine your needs:
  • What size objects do I want to scan? Scanners today scan items that range from the size of a quarter to a whole city.
  • Where will I do my scanning? Do I need a portable scanner or can I bring the objects I want to scan to a controlled location?
  • What will I do with the scan data and what are my accuracy requirements?
  • What is the experience level of the people who will perform the scanning?



About the Author: Susan Smith

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