Virtual reality: A powerful design and decision making tool in the construction industry
weather, mountain or sea, rocky or muddy grounds. In some parts of the world certain natural causes, such as seismic events and floods, have also played a significant role in the evolution or annihilation of various civilisations, emphasising the importance of correct decision making in construction.
Nowadays, the dissemination of science, the evolution in the material properties, the innovative construction methods, the constructional industrialisation and the impressive technological advancements in hardware and software allow building designers and construction engineers to make decisions with prudence but without fear. In fact, any proposed changes towards new architectural forms can predominate before these forms prove themselves of being earthquake resistant, economical, sustainable or harmonically fit to the environment. A three-dimensional world built in a computer virtual environment, escorted by an optimal decision making algorithm and assisted by experience in construction accumulated through the ages, enables building designers and construction managers to foresee and analyse the structural difficulties before these even appear.
The building design process is subdivided into three parts: the preliminary design, the final design and the detailing. The building designers usually have the time to go through an iterative process and, after analysing all data and parameters, to come out with an optimal and more or less error free solution. On the other hand, the construction process is separated into six stages: the structural framework, the gross-beton layering, the brickwork, the frame fitting for windows and doors, the plastering and the final detailing. Secure decision making at any stage is extremely difficult because each action taken usually affects processes in more than one stage. The construction managers usually deal with a wide range of multistage problems and must take fast decisions under pressure without being fully aware of what side effects might be created.
The effects of decision making in construction are not easy to be accounted for and surely not sufficiently exploited in current building design practice. This stands not only when traditional construction methods are used, as for example in small scale buildings in many Mediterranean countries, but also when highly industrialised procedures of either open or closed construction systems are followed, as those in large scale structures and massive developments. Before developing any decision making scheme, suitable building digital models should be chosen to represent the physical, functional and technical characteristics of the building. The total structural model follows the Building Information Model (BIM) scheme in order to allow a flawless integration with some virtual reality (VR) software. In this way the data of the physical and mathematical models of the building are handled successfully. Furthermore, if industrialised production is implemented, the structural components follow the Industry Foundation Classes (IFC) scheme. These data handling schemes, assisted by computer graphics, lead to an ultimate 3D representation of the building components whereas the continuous frame projections (approximately 60 frames per second) help to maintain a constant visual contact and thus generate of a virtual world.
The formulation of the building physical model is based on the following: Like any solid object, the building itself consists of solid structural components and layers, as beams, columns, slabs, footings, walls, doors and windows, railings, insulation, plaster, tiles, etc. Each solid component is formed by a set of surrounding surfaces and each surface is broken down into triangles paired by common edges. Especially when we observe the responses of the load bearing structure as deflections and stresses, or unusual structural geometries as hyperbolic roofs and parabolic walls, the number of triangles must increase in the intensive areas. The more triangles used for the surfaces the greater the accuracy of the image is, but at the same time this leads to increased computational time and therefore much slower decision making process. The snapshots of modeshapes participating in the overall seismic response of the building are shown in the figures here. These are actually animated in real time structural modeshapes, giving to the decision makers, designer engineers or construction managers, a qualitative perception of seismic behaviour of the building while the quantitative values result from modal superposition. All the above take place in real time, in an environment formed by continuous frame projections, maintaining a constant three-dimensional visual contact with the detailed building model and providing stereoscopic visualisation (via stereoscopic glasses), human interface, animating capability, speech response and all the technological features that any contemporary multimedia may offer.
This article points out how modern multimedia technologies can be used in the critical area of the construction industry for eliminating erroneous, misleading and sometimes catastrophic decisions. The innovative, straightforward and highly technological techniques presented add value to optimal design and decision making processes. After all, if the Chinese saying “one picture is equivalent to 1000 words” is true, then viewing 60 such pictures per second is equivalent to condensed human experience facilitating scientific observation and verification.