Time team: 4D building information modelling

14 December 2011 (Last Updated December 14th, 2011 18:30)

4D BIM tools incorporate time and scheduling into intelligent 3D models, bringing advantages in design and construction. Chris Lo looks into some of the most advanced software that BIM has to offer and asks if the benefits justify the higher costs.

The emergence of computer-aided design (CAD) in the 1980s heralded a major shift in the design and construction industries, a shift that pushed designers and engineers away from traditional hand drawing and into the age of the PC.

CAD marked the early steps of efforts to leverage the intelligence of computers to economise the design process.

"One of the primary uses for 4D on construction projects is to facilitate simple, visually intuitive guides for owners."

Today, the concept has been taken even further with the development of building information modelling (BIM) software, allowing construction teams to build information into 3D models.

This makes design software as useful during the pre-construction and construction stages as it is during the design process, the model seamlessly recalculating design elements based on new information.

As any building contractor knows, no design is completely immune to the demands of a construction project in progress, and BIM tools are gaining an increasing foothold in the market because they facilitate quick changes and flag up potential project risks, making for a smoother, more punctual construction process.

In the UK, the advantages of BIM have been officially recognised by the Cabinet Office. The Building Information Modelling Working Party Strategy published in June 2011 signalled the government’s intention to require that all public construction projects make use of "collaborative 3D BIM (with all project and asset information, documentation and data being electronic)" by 2016.

A new dimension: 4D BIM

One of the latest and most interesting developments in the BIM world has been the introduction of a whole new dimension. While 3D CAD and BIM comprehensively covers the dimensions of space, 4D BIM integrates time into the process.

As well as bringing a level of intelligence and easy collaboration to the design and construction of buildings, the fourth dimension ties this information to a project’s critical path method (CPM) scheduling, optimising the project’s supply chain, timelines and job site operations and placing all the data into a visually digestible 3D model.

One of the primary uses for 4D on construction projects is its ability to facilitate simple, visually intuitive guides for owners and stakeholders to get a detailed run-down of a project’s timeline, including animated simulations laying out the order in which jobs are going to be completed, along with the time they will take to complete based on a complex series of scheduling algorithms.

The fact that these accessible simulations take some of the design mathematics out of the equation also provides a distinct advantage in the bidding process, as a simulated 4D presentation serves the dual purpose of setting out a comprehensive vision of a contractor’s construction plan, proving that the contractor is up-to-date with the most advanced technology.

4D BIM has proved its worth in a range of large-scale building projects, but the ongoing project to build the massive Shard skyscraper in London provides a good recent example.

Mace, the project’s primary contractor, is using 4D BIM software from Synchro Ltd in conjunction with Asta Powerproject to create AVI videos for regular stakeholder presentations on the project’s progress.

Beyond simulation: 4D construction advantages

4D BIM software isn’t just about making accessible presentations for clients, however. The usefulness of 4D data runs far deeper, allowing contractors to make on-the-fly schedule and logistic changes, based on information from 4D BIM models, to optimise workflows.

"No design is completely immune to the demands of a construction project in progress."

Indeed, in a 2009 essay, co-founder of Finnish BIM provider Vico Software Olli Seppanen argued that 4D BIM must be viewed as more than a marketing tool for contractors to reap its true benefits.

"Owners should not be content with pretty movies but should pay special attention to the intelligence behind the schedule – quantities, resources, means and methods," he wrote.

"3D models are powerful tools to calculate quantities that are necessary to drive the schedules," Seppanen noted.

"Construction is repetitive work in locations. These locations can be visually identified in 3D models and the resulting location-based quantities can be used to calculate accurate durations for each location. This automated duration calculation enables crew optimisation to achieve continuous work-flow and reduced waste in the process. This optimisation can reduce durations by 10% without increasing resources."

In the case of the aforementioned Shard tower project, 4D BIM synchronises and reviews any changes to the construction programme and highlights potential inefficiencies, optimising key project aspects like the deployment of tower cranes.

"The use of 4D BIM and Asta Powerproject has helped Mace to evaluate and manage construction and logistical issues more efficiently – an enormous benefit on a project as highly complex as The Shard," commented Synchro’s CEO Tom Dengenis.

The 4D cost issue

"For many smaller projects, the cost that comes with using advanced BIM technologies is simply too high."

With all these advantages ranging from the early design stages all the way through construction, it would be easy to assume that 4D BIM methods would have become a ubiquitous industry standard by now.

However, economics affect a design-build project just as much as design technologies. In the current post-recession market (and even before) the emphasis for construction projects has been resoundingly placed on delivering a project efficiently and on the lowest budget possible.

For many smaller and mid-size projects, the associated cost that comes with using advanced BIM technologies is simply too high to be viable. In an interview with Design Build Network earlier in 2011, McCauley Daye O’Connell Architects director David O’Connell told us the extra time and money involved with creating intelligent 3D models could prove the difference between snagging a contract and missing out, especially when a designer is required to hit the ground running.

O’Connell warned against using unnecessarily sophisticated methods for projects that can be efficiently completed without them, comparing this practice to "bringing in an aircraft gun to shoot a bird".

"BIM models make an awful lot of sense…but you only get the benefit at a certain point in the project," O’Connell added.

"You’re incurring a lot of pain at the beginning to make the drawings intelligent enough to benefit you later." Evidently, even the critics of advanced BIM concepts like 4D recognise their benefits to the efficiency and reliability of a construction project.

But the economics of using 4D can put it out of reach of many designers and contractors, limiting its use to large-scale mega-projects where BIM’s built-in intelligence and visual presentation of complex data truly justifies its inflated cost. But as prices go down and software efficiency increases, as is inevitable, it’s likely that we will begin to see 4D BIM tools in use across a much wider swathe of design-build projects.