Look, no manuals: Metaio software is being used by VW to help workers servicing cars
The geometrical precision and realistic visual representation of which CAD systems are capable – whether they are modelling individual products or massive structures – is something that designers and engineers can largely take for granted. But the ‘virtual’ reality of the digital world and the physical reality of the real world can still sometimes be at variance with each other.
While a CAD system can model all the ‘hard’ components of an engine with total accuracy, the twists and turns of flexible elements such as hoses and wiring may not in practice follow the route prescribed for them in the ideal world of the digital model. That may seem a trivial matter but it would not be if a length of such material was positioned in a way that hampered the access that a service technician needed or came so close to a source of heat that it might melt or burn.
Such potential faults must be detected and corrected in between that first stage of computer modelling and production, which in practice means when physical prototypes are built and tested. Until recently that meant an iterative process in which someone moved between the digital and real worlds to check that they corresponded with each other. But now a relatively new technology is available that can help resolve that issue by integrating the digital and physical worlds in a single system that allows them to be compared directly and simultaneously.
This is augmented reality (AR). It involves pointing a video camera or some other device with similar capability at the physical prototype and then introducing into the image that the viewer sees information from the CAD database. So real world and corresponding digital information are displayed at the same time in the same field of view. It may then be a simple matter to see whether the ‘design intent’ of the CAD model has been successfully embodied in the product assembly or whether there is some disparity between them.
That scenario is confirmed by Thomas Johanneau, who works with the industrial solutions department of Munich-based Metaio, one of the big suppliers of AR software. The company was founded 11 years ago by its chief executive Dr Thomas Alt, who had previously been a researcher with Volkswagen. Its first project was an early implementation of AR with Volkswagen. Metaio now employs 100 people in Germany, with another 20 in the US.
Johanneau says Metaio has a range of AR products suitable for different applications. An investment of as little as ¤5,000 might be enough to get a company started as an AR user provided it was prepared to do all the work necessary to integrate the software with a CAD system. He says the Metaio software could be integrated with any mainstream CAD system. Individual CAD vendors may also offer AR as part of their product portfolio.
Whatever the source of the software capabilities, the basics of the application technique remain the same. A device is used to produce a video image of the real product or location in question and relevant digital imagery derived from the CAD database is integrated with that image to enable an evaluation process to take place.
The technique can be used with a variety of hardware devices. Johanneau says they could include a video camera linked to a static display screen, or a handheld tablet-type computer with the camera on one side of the device producing an image which is viewed on its own display screen.
A device as compact as a smartphone could also do the job. There are other options, such as a transparent ‘see-through’ screen in which the CAD data would be superimposed on a direct view rather than a video image of the product, or a headset or goggles worn by the user. Similarly the processing of the data can be carried out either by the hardware involved or remotely using an internet connection if there is sufficient bandwidth to ensure that the CAD information can keep track of camera movements.
Some sort of ‘calibration’ procedure will be necessary to ensure that the CAD data is displayed at the same size as the corresponding physical object would when viewed from the same angle and distance. Johanneau says that one Metaio customer uses a camera mounted on a robotic arm to measure key parameters before operations begin. A simple alternative technique is to place a calibrated marker – possibly nothing more than a piece of paper – in the field of view.
Screen tests: Do the CAD models and actual products match up?
Product development is an obvious application area for AR but it is not the only one. Another is in the provision of training or on-the-job support for the maintenance of in-service products. This is where Metaio software is being used by Volkswagen in an initiative called Marta or mobile augmented reality technical assistance, which involves providing support for workers servicing the XL1 vehicle. Servicing information is displayed on tablet computers after they are pointed at a car. So, instead of having to refer to separate manuals, employees can see on-screen labels that identify parts in their precise locations on a real vehicle. They can also call up work instructions along with details of the necessary equipment.
Meanwhile, one of the CAD software developers that offers an AR capability on its own account is US-based SolidWorks. Rick Chin, director of product innovation, says the company introduced AR last year as part of its eDrawings program that allows users to view CAD information on handheld iPads and iPhones.
According to Chin, the company initially regarded the capability as most likely to appeal to developers of relatively small-sized products, such as domestic appliances. It envisaged its AR offering as an ultra-rapid purely digital prototyping technology.
It can make possible the examination of a virtual model of an intended product to check such factors as size and appearance within days of the first design information being created within a CAD system. But a conventional rapid prototyping technique such as stereolithography would be necessary to make physical models suitable for assessing ergonomic issues such as those related to touch and handling.
SolidWorks’ AR capability is very much aimed at the desktop. A simple paper marker placed on a table is all that is required for the combined camera and display device to be able to calibrate itself correctly to show what an intended product might look like if it was there for real. The capability could be enhanced by having a comparable real product in the same field of view so that they could be assessed side by side.
The AR viewing capability is not static. The digital image can be rotated on-screen as in a conventional CAD system, and it will also rotate if the user walks around the desktop while continuing to point the viewing device at it.
Chin says SolidWorks has built some quite specific functionality into its AR capability to enhance its utility as a design verification tool. There’s the ability to create a digital ‘cutting plane’ at a set distance in front of the viewing device. So, as the viewer moves the device towards the virtual location of the product, they will be able to see through it on a progressive basis as its internal components become visible.
Chin mentions one particularly inventive and unexpected use of the capability – as a sales aid by a company that makes valves. To show off products, sales staff previously had to take around with them a cumbersome and heavy metal valve that had been partially cut away to show its inner workings. But now all they need is a slim iPad device.
What that demonstrates is that when a new technology hits the market its effectiveness will depend on the inventiveness of its users. By itself AR is just a very clever software-based image manipulation technique, but there is already enough evidence to show that it can provide some genuinely useful capabilities throughout the whole product lifecycle.
Design potential: SolidWorks offers AR capability in eDrawings