In the Engineering Faculty at the University of Kassel, there are currently 24 professors researching and teaching at six institutes. The Institute of Production Technologies and Logistics consists of four divisions, one of which is Production Organisation and Factory Planning, directed by Prof. Dr.-Ing. Sigrid Wenzel. One focal point of this division's research is the digital factory.
At the beginning of March 2008, Prof. Wenzel organised a kick-off event at her university, titled “Digital Factory – Benefits and Opportunities”, where, amongst other things, the Digital Factory competence laboratory of her division was presented. This competence laboratory can be seen as a basis, on the one hand for innovative research projects about the digital factory together with industrial partners, and on the other hand for a research-oriented way of teaching and learning in order to prepare students for the application of digital planning methods in the industry. That's why the kick-off event was not only visited by students from Kassel, but also by a number of business representatives. The programme included lectures from the ship building and automotive sectors where the speakers made it clear that the production processes in these sectors could not be managed without digital planning methods and “virtual reality”.
“Virtual reality” may still sound like science fiction rather than engineers and planners. Yet a closer look will reveal that simulation and visualisation are the main pillars of the digital factory, which has obviously already become a part of the research sector. And in industry, state-of-the-art factories cannot do without realistic simulation of production processes.
If, for example, the shipbuilder Meyer in Papenburg represents the whole construction process for their next ship down to the smallest detail in a computer-simulated factory, and can therefore lay down exactly where, when and how a certain pallet has to be processed in order to enable the overall process to be run as planned, then this is far more than a mere numbers game. The aim is optimisation of processes and reduction of production costs.
In industry as well as at universities, elaborate technical systems are necessary to move within the virtual factory in all three dimensions in the same realistic way as in the real production hall or on campus. For this purpose, large-area three-dimensional projections are utilised.
3Dims GmbH of Frankfurt were commissioned for the technical realisation in the competence laboratory of the University of Kassel. Directed by Friedhelm Birk, this enterprise specialises entirely in “virtual reality”. 3Dims realise special applications for three-dimensional projections with enormously complex technologies and fascinating precision.
In Kassel, the 3Dims specialists built an active stereo projection system consisting of two individual back projection modules. The system, which is distributed by 3Dims under the name of Buenavista CL 2800, can be utilised as a 180 degree power wall or in a 90 degree L-shape. Depending on which method you choose, you can either watch one large image or two matching images arranged at right angles. The projection screens are 2.9 x 2.2 metres each for this purpose. For projection screens of formats larger than two metres, 3Dims rely on the quality products of the US company Stewart Filmscreen.
There is a mirror mounted at an angle behind each of the projection screens, and a projector installed in a special mount above each mirror. A Christie Mirage S+2K works at the heart of each of the Buenavista modules. This 3-chip DLP projector alternately supplies the picture for the right and for the left eye at 120 Hz frequency.
“This is the point where almost all the suppliers of projectors pack it in”, Friedhelm Birk, managing director of 3Dims, explains: “Christie is the manufacturer who can cover and deliver the whole range and also supplies the best support. Whenever we have a problem that we cannot solve ourselves, a Christie expert will come and help us – as was the case here.”
In order to be able to perceive the 3D world, every viewer has to wear a pair of shutter glasses. These glasses are controlled via an infrared signal which also controls the projector, and they allow the three-dimensional image to be viewed from different perspectives. With the Kassel installation, the organisers didn't just install a flat power wall with one projector; they synchronised two units to achieve one large, homogeneous image sized 5.8 x 2.2 m.
Three high-performance computers – one master and two slaves – all fitted with high-quality Nvidia Quadro-FX graphics adapters, act as sources. These machines have a lot to process: the master divides the image first into two signals for the right-hand and left-hand projectors, and then also into chronological order for the right and left eyes of the viewers; the slaves are responsible for rendering the entire image material. After all, we are not talking about films being played, but of three-dimensional image worlds in which the viewer can move freely at his or her pleasure.
If Prof. Wenzel has her say, the 3Dims company bus will soon visit the University of Kassel again because the system is extendable and will be completed by a third module as soon as possible. Then the system could be utilised for U-shaped rather than L-shaped projections, and thus almost realise a virtual room.
The five-member 3Dims team, with a second small office in Munich, could deliver such a module within six weeks without any difficulties. Yet first of all the necessary funds have to be raised by the university.
In the future, a tracking system will also be applied in Kassel. At present you have to use a mouse for navigating the virtual world; the tracking system will respond simply to the appropriate motions of your head.
Even though such a visualising unit is an expensive venture, it certainly pays for industrial applications, as one of the members of the meeting explained: “If the system helps us avoid just one gross error, it has already paid for itself.”