VR/AR Structuring the field
From EuroVR Knowledge Base
Contents |
Introduction
Virtual Reality (VR) technology is still a rapidly evolving and diversifying field. Its evolution has undergone nearly two decades of research and development and has reached, on the one hand, a decent maturity, and on the other hand it has still not reached the mainstream, either in the professional field or in the home or entertainment field. VR-environments differ from conventional desktops in the sense that they embed the user in a computer-generated data environment. These systems have the following key properties e.g. as described in (Burdea and Coiffet 2001):
- 3D-representation and perception
- Spatial interaction in real-time
- Sense of Presence and immersion
VR-Technology has strong links with human-computer-interaction (HCI) research where it can be considered a specialized part. To define the research field of VR-Technologies against other HCI research areas and also the specific application oriented research fields, the following definitions seems appropriate:
“The VR-Technology field focuses on spatial multi-sensory representation, interaction, and presence, combined with real-time simulation techniques and high level management of the handled virtual environments.”
Well known examples are systems which drive head mounted displays or 3D stereoscopic multi-wall environments, such as CAVE-systems (CruzNeira et.al. 1993). Although many ideas have been exchanged between the Information and Communication Technology (ICT) mainstream and virtual reality technology, the usage is still limited. The main issues can be summarized briefly:
- Lack of sufficient realism or complexity
- Insufficient usability
- Lack of economical content creation processes
- Only partial process integration
For all these issues there exists partial or specialized solutions such that VR-Technology is already used profitably, but there is no general solution for all application cases. A trend in custom-built applications has evolved, with only a small number of limited general applications reaching out to the masses of potential users across market sectors. Individual and small-size applications have been sufficient in proving so far the advantages of the VR technology in several sectors among which the industrial and the training fields are the most representative. The situation might be comparable with the field of artificial intelligence, where many useful techniques are today common knowledge, e.g. object oriented programming, but the main goals of the early days such as the “General Problem solver” have still not been reached or have been abandoned (Russel and Norvig 1995). Can a similar pattern be observed with Virtual Reality technology? And if so, what is the meaning and how to exploit this observation? Thus it is still crucial to facilitate the adoption of Virtual Environments (VEs) in industrial processes and assess the impact of its “penetration” into the workplace and everyday life in terms of cost-effectiveness, health hazards and side-effects of users and its impact on the actual working environments, on an individual and organizational level.
Technological Challenges
Today the VR research community faces several challenges which have to be solved to be able to have benefit for the large community of IT users. These challenges range from completely novel technologies to very obvious linear improvements. They can be structured in four areas of technology, interaction concepts, integration and socio-economic issues.
- Technology
- Simulation technology (hard and software) in necessary accuracy not real-time capable and vice versa
- Bandwidth for stimulation of the human sensory system to low (e.g. display resolution, colour depth, frame rate, field of view, etc.)
- Spatial registration and tracking of user and environment not accurate and not available in a really ubiquitous manner
- Lack of efficient application/content development systems
- Insufficient synchronisation of multimodal and multi-sensory components
- The completely unencumbered use of equipment is still not possible.
- To provide ubiquitous access to virtual environments especially in AR improvement of power consumption in portable devices is necessary
- Interaction concepts
- No immersive 3D-UI paradigm (comparable to the 2D WIMP paradigm)
- Spatial interaction not properly understood at cognitive level
- Computer mediated “Presence” and its impact not fully understood
- Integration
- Lacking interoperability of VR systems and related application such as CAD, CAE, PLM, etc.
- Lack of widely accepted standards (Data, Behaviour and Interaction)
- Lack of integration of VR/AR in existing applications and workflows
- Socio-Economic issues
- VR-systems are still too expensive
- No valid return-on-invest (ROI) evaluation
- New interfaces break with learned habits
These categories are interdependent and advances have to be achieved probably in all areas to progress significantly. But there are drivers for change which push VR-technology in terms of requirements but also in terms of funding and resources.
Principle of VR systems
The generalized view on VR/AR-Technology and its applications is an interactive computer mediated or generated environment with the user, his body space and its sensory affordances in the centre of research. It can be described by the following diagram:
Aspects of Virtual Environments
It is now possible to structure the technologies and its application in more detail, which leads naturally to a taxonomy of VR-Technology. A taxonomy of VR-Technology on one hand helps to understand the inter-play of the used components and the level of sophistication and on the other hand it characterizes its systems and helps therefore to see common-alities, differences and novel combinations. The here proposed structure is based on the works of Milgram (Milgram 1996), Robinett (Robinett 1992) and the INTUITION roadmap.
The following aspects help to classify and characterize systems and also research areas.
- Interaction Modalities
- Spatiality
- Degree of embedding the physical reality
- Collaboration Level
- Space and Time Mapping
- Fidelity of the Content
- Content Dynamics
Content and Tool
The application of VR/AR-Technology is influenced by two different general categories, which are labeled “content aspect” and “tool aspect”. This is illustrated in the following figure, in terms of the most relevant characteristics.
Figure 1: Content and tool technology are combined to create Virtual Environments.
VR-Technology combines the qualities of media and tools in a unique way. If the “content aspect” is considered, the emphasis is laid on the ex-perience and perception of 3D-environments such that the user feels con-sistently present at computer generated or augmented locations. This implies believable behaviour and appearance of these virtual worlds. If linked to our intuition or experience the “content aspect” leads to the provision of real-time physics and accurate realistic rendering. If, on the other side, VR-Technologies are seen as a specific part of mul-timodal interfaces the “tool aspect” is in the focus and the main point of research and development is dedicated on spatial interaction technology comprising multimodal rendering, synchronisation and real-time issues. It is also obvious that there are interdependencies between tool and content, as it is known that interaction reinforces presence. Taken a broader view:
- the “tool aspect” of VR/AR-technology cannot be separated from other human machine interaction research,
- the “content aspect” cannot be separated from other 3D-content technologies as foremost computer game technology but also 3D-CAD and 3D-simulation
Both aspects are reflected by VR-Technology development and vice versa.
To be able to provide a seamless integration of the user in an informa-tion environment, many technical disciplines are involved ranging from psychology via computer science to mechanical and electrical engineering. The technologies which VR-systems are based on are illustrated below:
