Reverse Engineering Is Not Stealing
October 8, 2012
New ideas are nothing but repackaged old ideas. Advances in 3D scanning have given design engineers the ability to turn any solid form into a virtual one we can prod, test, manipulate and recreate.
It’s been said there’s no such thing as a new idea: every form and function humanity takes credit for has was simply aped from nature by highly intelligent apes. True genius is the ability to recreate and incorporate applicable ideas to create a new concept. Today, 3D scanning is making it easier for us mere apes to better harness the forms that we’ve already thought up.
Reverse engineering evokes images of theft, of taking something that doesn’t belong to you and copying it. The reality is quite different—every one of us has reverse engineered something for perfectly legitimate purposes. If you’ve ever picked up a micrometer or a ruler to measure something, and then built something based on those measurements, you’ve reverse engineered.
Of course with modern CAD technology, reverse engineering has taken on a whole new level of capability—and consequently culpability—and importance to both small and large businesses. With 3D scanners, you can capture the dimensions and shape of just about anything in short order. Combine that with the ability to bring the scans into CAD, CAM, 3D printing, simulation and analysis software, and it’s easy to see why manufacturers in almost every industry engage in reverse engineering.
The modern reverse engineering process, which involves 3D scanning an object and using that measured data to create a CAD model, is being used throughout the design and manufacturing process for all sorts of products. Wherever there is a need to get the physical world into the digital one, people are reverse engineering using one method or another.
Using a 3D scanner to do so makes sense when parts are complex, freeform in shape, accuracy is critical and when time is short. This includes the iterative prototyping process, where you might 3D print or otherwise make a prototype, modify it, then record those modifications digitally. It also includes situations where one design depends on another — such as fitting new components into an existing assembly -— and there’s no 3D CAD model available. The great majority of new product designs depend at least in part on existing things, which is why so many companies are now embracing reverse engineering.
There are more than 100 different 3D scanners available today, with systems that cater to all sorts of different needs. These include devices that scan optically (digitizing the outsides of objects) and those that scan in other wavelengths (like industrial CT that capture external and internal geometry). Optical scanners are the most common, and among them are two primary technologies: laser and structured light. Laser scanners typically pass a red laser line across an object, and using triangulation techniques, determine the distance from the scanner to the object. Structured light scanners project specific patterns of light onto an object, and by comparing the differences between the patterns reflected back to the scanner, they can also determine the distance from the object.
In addition to these technologies, which are suited for relatively small objects (from dimes to car fenders), there are other approaches that make scanning larger things possible. Most medium and long range scanners also use lasers, but instead of triangulation they look at the time it takes for light to travel between them and the object. These systems make it possible to 3D scan a car, aircraft, or even an entire building.
As industrial design becomes ever more important to successful product launches, consumer products, electronics and white goods manufacturers are employing 3D scanning to bring the physical prototyping process into their design work flows. This enables design inspiration from existing objects, as well as uniting the world of clay modeling and CAD.
Medical devices, especially those that need to fit in or on the body, are often designed around complex organic shapes. Virtually all in ear hearing aids are now made through a combination of 3D scanning, modeling and 3D printing. The same is true for orthodontics and prosthodontics.
Car parts are prime candidates for reverse engineering. For example, sheet metal is very freeform in nature, with complex curves that are almost impossible to draw on screen in software. Other vehicle components are also complex in shape, like castings and forgings. For these reasons, many aftermarket parts are designed using a process that starts with a 3D scanner. Automakers themselves use 3D scanning to record the geometry of their tooling as it exists on the factory floor, so if it breaks they can quickly make another.
The technology is used heavily in aerospace as well, from capturing the complex geometry of turbine blades in a jet engine, to remanufacturing parts for old airframes (think of the B-52 bomber, which went into service in 1955, and won’t go out of service before 2045).
All 3D scanners create essentially the same thing: a point cloud, made up of millions of individual measurements in 3D space. To turn point clouds into data that can be used in CAD, CAM, 3D printing, etc., the second step after scanning is to process the data. This is where the engineering part of reverse engineering comes into play. The most common approach today is to use the point cloud as a template of sorts, over which you create a CAD model. This approach yields a fully functional CAD model, often referred to as a parametric solid model. It takes a fair amount of effort because it involves understanding the function of the object and making design decisions about it, but the result is a manufacturing-ready CAD model that can be edited later too.
An alternative method is to create a mesh and/or NURBS surfaces from the point cloud. This method is often simpler than building a full parametric model, with the trade-off being that the model will reflect the imperfections of the scanned part, and won’t be editable in the same way a normal CAD model is. It’s the older method of reverse engineering, but still applicable when you want a verbatim copy of a physical object.
Return on Investment
3D scanning, like all technologies, is just one of many tools available to solve certain problems. Properly applied, it can save massive amounts of time over traditional measure-design-make work flows. In some cases, it makes the impossible possible as well. It isn’t as simple as taking a picture, though. It’s rare that someone simply wants to copy a 3D object -- more often, we want to modify an existing design, improve it, add value to it, then make it. The real value of 3D scanning is that it brings accurate representations of the real world into the rich ecosystem of CAD, simulation, 3D printing and other design technologies most companies have today. That capability allows innovators to compress design cycles, save money and bring better products to market faster.