Good timing

It can be compellingly argued that over the last 25 years, the construction industries of the industrialized world have become fragmented, bloated and inefficient. Ironically, in a drive to become leaner, with more focused disciplines, general contractors have been carved up and replaced with a plethora of consultants and sub-contractors, all specializing in a particular niche, supposedly to provide a better product for the client. However a number of studies have highlighted quite the opposite, with some quotes claiming an 80 per cent failure of projects to deliver on the three key objectives of time, budget and quality.

The streamlining of the industry through the 1980s and 1990s and the culling of staff that occurred as a result has also left a dearth in skilled management. This at a time when the construction industry is encountering unprecedented levels of business across the globe, exacerbating the condition and leading to a situation where there is a general lack of understanding of the requirements needed to deliver projects. Existing training and processes can only fill some of these gaps, so senior management are therefore placing more and more emphasis on technology to solve some of the issues, including communication of project deliverables and coordination of the interfaces between contractors.

4D modelling (also known as 4D planning, simulation or choreography) has emerged as a way of achieving these requirements. It might be doing the discipline an injustice, but in essence 4D entails linking a 3D CAD model to a construction program, creating a time-based model of the construction sequence. This then enables testing of the program in a graphical environment and communication of the results to all stakeholders involved in a project.

On the back of an explosion in the use of CAD-based design tools and an increasing use of IT generally, transferral of this information into the construction realm ticks all the right boxes when looking at the complete life cycle for project information. Add to this the ability to use this information to better understand the design through facilities management product links and it appears as a win-win for all parties, including the client.

Unlike a normal design model, 4D models encapsulate all the elements required to carry out the construction process, incorporating logistical items such as hoardings, temporary works, tower cranes and so on. In addition, the build sequence is broken down from the component parts so that activity management (tasks) can occur not just at a point in time but also at a location within the built environment. So for example, a slab will be broken down into the number of pours, the cores modelled floor by floor while the mechanical and electrical may be sectioned into a series of work zones.

By doing this, a realistic simulation of the tasks that make up a project can be viewed in a single source. In addition, through the process that is followed, other benefits accrue as the 3D models created for the various elements of the program are cross referenced, forming an additional level of design coordination to that currently undertaken by the design team. This helps to identify conflicts at a much earlier stage in the process and thereby allows issues to be managed out before they impact on the design delivery program and thereby the manufacturing and installation

In 4D, the construction program is initially developed in the usual manner by either a specialist project planner or the project manager using standard project software such as MS Project, Asta Power Project or Primavera. What differs is that this is then expanded exponentially by using the elements in the model, allowing the skeleton of the program to be fleshed out, giving much greater levels of information to use in the process going forward. The level of detail shown in both the program and the model will naturally be dependant upon the type of 4D models being constructed, be they for bid tender, pre-construction, construction, and so forth.

This is crudely expressed as a monthly, weekly or daily task breakdown, although it encapsulates far more than this in a process management environment. The model will mirror the work breakdown defined for the site and the program tasks, otherwise it cannot be sequenced properly. This means (at the very least) elements in the model have to be built as semi-detailed design spaces so they can be programmed as multiple activities, but it also allows for change management to be measured against a time element.

4D on Canadian projects The theory behind this sounds great but, some may ask, how do we implement all this technology when even computers are sometimes seen as too technologically challenging to use on construction sites? That is where the specialist planning and coordination consultant comes in, and U.K.-based A3D is at the forefront of this new and emerging role. Since 1999 the company has been pioneering the use of advanced 3D technologies across the globe and in 2002 became involved in its first North American project, Minto Gardens, a 34-storey apartment development in Toronto. Other projects followed, including being part of Aecon’s bid team for the William Osler Hospital project in Brampton, Ont., and a second project with Minto, the much larger 53-and 39-storeys twin tower MidTown development in Toronto.

More recently, A3D has teamed up with Michael McGrath of Tucker Hi-Rise to launch a new concept in managing residential high-rise developments, based on the benefits that come from working from a base 3D model, with the latest Great Gulf Homes project, The X, the first of a series of projects proposed to use the technology.

Reading a Gantt chart in conjunction with a set of drawings is difficult for even experienced planners to interpret and is certainly challenging for those un-familiar with the discipline to visualize. There’s great benefit to have on screen a snapshot of the issue under discussion so at least everyone is talking on the same page. It serves to focus people’s minds and get straight to the point of resolving the issue of the day. It also helps to engage the trade contractors in thinking through their aspect of the work in more detail well in advance of arriving on site.

4D has been used in Canada as part of a tender package so that certain critical areas could be better communicated up front, giving the tender party greater confidence that the project team had thoroughly interrogated the proposed plan at that stage in the project. Alternative tender submissions could also then be better analysed for not just cost implication but also delivery implication, which can be critical for both commercial and residential customers.

Implementing 4D The PAL (Planning and Logistics) models come as a single file and with one click you are taken straight into the model. Despite all the fancy navigation tools to zoom and fly around, what really makes the difference are pre-saved, zoomed-in views of all the key parts of the building such as isometric views, elevations and specific zones. It allows even novices to go straight to the area of interest in a single click, using terminology they are familiar with. Another important function is the calendar; so if a sub-contractor wants to see what is supposed to be happening on a future date, he just clicks on the date and the building jumps to that point in time. It is uplifting to see technophobes huddled around a computer screen arguing a particular point and getting real value out of the system, while not really realizing they are playing with the latest in 4D technology.

Current computer-generated images or animations of completed buildings are commonplace and play an important part in helping people understand the concept of a new building. But to be really useful, what is required is the ability to see a snapshot of where the build will be at any given point in time and from any point of view, including being able to zoom into details.

And that is just the
beginning, because the reality is that construction managers and planners need a graphic that will clearly show what activities are planned for a certain period of “look ahead,” be it a week, month or even longer. When you think the process through, you realize a simple animation is just not going to deliver that and some kind of dynamic model is needed.

Chris Allen is director of operations at London, Eng..-based Advanced 3D Technologies Limited (

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