Back in the 1990's, before the degree programme of Information Technology existed, factory simulation appeared within the degree programmes of Automotive and Transportation Engineering, Food Processing and Biotechnology, Wood Technology and Construction Engineering. And it was during this period that the Polytechnic was introduced to simulation, computer stereo vision and virtual reality technology. At that time, they used Deneb's Quest and IGRIP simulation programmes, which were pure OpenGL software, and ran only on SGI hardware.
“As a result, our interest in virtual reality grew to the point where we began to dream about having our own cutting-edge virtual reality space, in order to compete with other polytechnics,” declares Seinäjoki Polytechnic Laboratory Engineer, Tapio Hellman.
In 1996 a new degree programme in Mechatronics (a discipline combining mechanics, electronics and computer control) was introduced in the School of Technology in response to the demands of the machine shops and engineering works in the area.
The popularity of the degree programme rendered the School of Technology insufficient and Seinäjoki Polytechnic started to make plans for a new technology centre. This became reality in 2003 when the IT related degree programmes from both the Business School and School of Technology combined to form a new School of ICT, in the new ‘Frami’ building. This building also encompassed the research network of EPANET, a co-operative network of Finnish universities in South Ostrobothnia — part of which was the professorship of Virtual Technology, which was launched in 2003.
This professorship would benefit from the facilities of the Virtual Reality lab and CAVE — and like all 15 laboratories in the School of ICT the CAVE was funded by the Joint Municipal of Seinäjoki Polytechnic, with around 20% support coming from an EU Project.
Procurement and Specification
Seinäjoki Polytechnic started to research the world’s existing CAVE facilities via extensive browsing on the Internet — and with help of Mika Iltanen, who worked as a director of VR Centre in Tampere University of Technology.
The Polytechnic’s first contact with IDCF had been during the EU-wide competitive bidding of IT-related hardware for the ‘Frami’ Technology Centre in 2002-2003. The contract was divided into several separate tenders and IDCF won the competitive tender for the procurement of the 40 DLP projectors.
In 2004 Seinäjoki arranged an EU-wide competitive bidding concerning the DLP projectors, mirrors, projection surfaces and the installation for the CAVE — aware that there were a number of companies capable of delivering a demanding immersive environment.
“We received 17 applications to the bidding, and finally five companies submitted tenders. We knew that there are only two manufacturers of this class of projectors in the world, one of whom was Christie,” said Tapio. Only five suppliers were left in the bidding — two of them offering the Christie products — and this proved decisive.
Led by Christie systems engineer, Andy Symonds, Christie undertook the procurement for the design and installation of a top-of-the-range 3D immersive environment — a complete surround environment, using special coated screens, and mirrors, which folded the light path to reduce the throw distance.
The initial tender request had been based on both four- and five-sided cubes. Initially the Polytechnic had opted for four in view of possible financial risks before reverting to the original maximum number of screens and sides, “since this would be much more difficult to achieve later — from both an economic and workload perspective,” said Tapio. He rationalised that having a four-sided CAVE — when the floor projection is accomplished underneath the floor — would be a waste of immersion and quality. He believes five sides to be the optimum number “since six in a cubic CAVE creates acoustic, ventilation, cabling and orientation problems, and in a non-cubic CAVE environment such as ours — with an image ratio of 4:5 on every screen — six sides would not be feasible at all.”
Seinäjoki Polytechnic CAVE is almost a cubical space, which consists of five rear projection surfaces (left wall, rear wall, right wall, floor and the ceiling). The space itself measures 3-metres x 3-metres (with a height of 2.4-metres) and the glass floor will support over 5,000 kg of irregular load. The optimum immersive experience is achieved with between one and five people inside the CAVE at any one time.
The screens are of an acrylic-based material, with an optical diffusion surface on the viewer's side eliminating any hot-spotting caused by an extremely bright projector, and distributing the rays of light evenly.
On these surfaces is projected a 3D active stereo image produced by a Silicon Graphics Onyx4 UltimateVision computer, with 10 MIPS R16000-processors running at 700-800 MHz, 14 GB of shared memory, 1.6 TB RAID-hard disk system, 6 ATi FireGL SG2 OpenGL-graphics pipelines, Gigabit Ethernet interface and Iris audio processor. Processors may be added up to 16 and graphics pipes up to 8. Operating system is IRIX 6.5.25.
The Polytechnic has also ordered a five-PC cluster, which may also be used as an image generator for the CAVE, running Windows and Linux software (in addition to SGI IRIX). “This is a current trend across the world’s VR labs — and we want to be part of the progress,” says Tapio.
The image is produced by Christie Mirage 4000 DLP projectors, each of them from corresponding projection.
The computer generates these five projection images, which consist of geometric elements, bitmap images and possibly video. Furthermore the system reacts with minimum response time to the movements of the viewer in the CAVE cube, rendering an image on each wall constantly according to the CAVE user’s position and orientation, and the changes of the input device used by the CAVE user.
An active stereo image will be rendered so that each eye will see its own image with liquid crystal shutter glasses at a frequency of 2 x 45 Hz (with IR used to switch them on and off repeatedly 96 times per second). The refresh rate of the projectors is synched up with the flicker rate of the shutter glasses so that every other projected frame alternates between a left eye and right eye image. (The shutter glasses block out the image not intended for the blocked out eye, effectively supplying each eye with its own personalised/customised 3D image).
To be able to use the floor and ceiling projection effectively, the image needs to be produced in active (rather than passive) stereo — with different polarisation systems. “CAVE is a VR environment, where the user may take a glance behind a virtual corner and take a look underneath a virtual table. This gives the user an immersive feeling of actually being there even though he is not — it is just virtual,” explains Tapio.
Seinäjoki Polytechnic operates a wide variety of software which it believes to be among the best in the world for this environment. This is divided into three main groups:
- 3D-modelling and conversion software
- Presentation software
- Software libraries
This is principally applied in Mechatronics, which includes factory automation, robotics, etc. “Since we are not a university our main goal is not in doing research in VR but rather applying VR into practice,” explains Tapio. “Like some universities we don’t believe that open source software is the only right way to go VR.”
Most important of the presentation software packages are VRScape from VRCO, Walkinside from VRContext, COVISE from Vircinity, Vega Prime from Multigen-Paradigm, CATIA ENOVIA DMU Review from Dassault Systemes, Division Reality from PTC and VR4MAX from TreeC. They may design applications in C and C++ programming languages with software libraries such as CAVElib from VRCO for basic CAVE application programming, Open Inventor from Mercury Computer Systems for higher level immersive applications and Vortex from CMLabs for physics, dynamics and collision. Applications may be created on SGI IRIX, Linux and Microsoft Windows platforms.
The CAVE and VR lab will be used and developed by the students of the Information Technology degree programme (specifically Embedded Systems, Mechatronics and Software Engineering), the staff and the professor of Virtual Reality Technology with his research group.
But none of the possible application areas of VR technology will be discarded. CAVE will be used within embedded systems, Mechatronics, 3D mechanics and kinematics design, modelling, simulation, analysing, prototyping and also possibly within study related business projects. Other possible application areas are architectural, construction and civil engineering, entertainment, culture, medicine and other sciences. In this way it will not be a remote and insulated place but an integrated part of the studies. The CAVE facility will also be available for rental by any company.
Tapio Hellman says that having attracted a high degree of media attention and a number of distinguished visitors, the CAVE is being pitched as a "must" place to visit for every foreign and domestic group of students and professors.
Although the system is fully commissioned, the mission for the Polytechnic to create the best virtual environment in Finland is only just beginning, he says. “Seinäjoki Polytechnic will never be ready; like software, it will just get better and better !”
However, he is quick to emphasise that there is no requirement to make the CAVE economically profitable. “I think that some high-quality CAVEs have proved to be a disappointment because the expectation of productivity or profitability has been too high. The money inveted in the CAVE or VR lab will not come back in the form of currency but in the form of knowledge and research achievements. While it will take several years of study to achieve positive results I believe it is possible to become world leaders in five-to-ten years.”
Christie’s Simon Smith is similarly positive, crediting the vision of both the end-user and partner in the realisation of such an adventurous project.
While Christie has delivered CAVEs, from three to six sides, throughout Europe, he believes this to be their best looking cube yet.