Building Information Modelling (BIM) will transform and dramatically improve the way building designers specify products. David Wheeldon reports.
The 3D design, modelling and simulation technology known as BIM is pegged to takeover from CAD as the preferred design tool by the architectural design community. It's happening rapidly at the big end of town, so what's the hold up on the industry wide takeover?
For BIM to work to its potential, it's crucial that the digital 'objects' reflect the real-world specifications of a product. That means manufacturer-specific objects are required, containing all the information necessary to the architect or designer.
This is the beauty of BIM. Designers are considering the actual objects and assemblies that would be used in the building. When simulating the performance of various design options, designers can compare them in a meaningful way. It's an early representation of the real deal like never before.
The technology will allow specifers to search and locate products by type and the performance criteria they need. All the properties a specifier would need to consider are embodied in the BIM objects, from materials, size and shape to U-values and life-cycle-assessment criteria.
For Rodd Perey, Group Design Technology Manager for Architectus, it already means the ability to make better decisions, earlier in the design process.
"Products are able to be tracked, and counted and costed from the start. This has huge impacts on the design process: visualisation is simple, so we can get informed client sign-offs at an early stage; we are measuring areas, and carpark numbers, seat counts, or whatever is relevant, continually, so we can keep the design very close to the brief requirements; we can contain information about the site constraints within our models, and can see aspects like shadow planes in our models as we develop the design."
NATSPEC, the National Specification System of Australia, is a strong proponent that digital information will "provide improved methods of design, construction and communication".
As Neil Greenstreet, senior architect at NATSPEC, says: "Information represents the greatest untapped potential. The 'I' in BIM will be the most transformative element of this technology".
The Australian Government is also convinced, and has been for at least the past year, following the strong case put by a Built Environment Industry Innovation Council (BEIIC) report.
Since then, the Australian contingent of buildingSmart, part of the International Alliance for Interoperability, has been leading development on a National BIM Roadmap. With strong industry support, they've put key priorities to the Federal Government.
We need object libraries
At the top of the list is providing access to consistent and compatible objects, based on information from building product manufacturers, for use in software applications. What is needed is a something akin to a public library for BIM objects.
The Sustainable Built Environment National Research Centre (SBEnrc) has a research project underway on object libraries aimed at developing a consistent framework. This is supported by the Building Product Innovation Council (BPIC), which represents Australian product manufacturers. The Queensland Department of Public Works and NATSPEC are partnering in the development, which is intended to make the objects available at no cost to the end user and for the objects to be compatible with most software applications widely used in the industry.
It allows manufacturers to create a generic BIM object, for example a window product, which can be transformed by manufacturers into their proprietary object - following a standard set of properties.
The problem at the moment is that an object created in one of the major software packages, say Revit by Autodesk, will not work in another, like ArchiCAD by Graphisoft or in Bentley BIM.
The standardisation of properties would create a level playing field for manufacturers. It would also support sustainable building practices, with products compared on a like-for-like basis regarding product life cycle analysis.
Currently manufacturers are able to choose a green product rating system that best suits, favouring their product over competitors.
That explains why BPIC last year launched a project to develop a standardised national database called the Australian Life Cycle Inventory (Aus LCI). This was done in collaboration with the Australian Life Cycle Assessment Society (ALCAS) and the Green Building Council of Australia (GBCA)
Greenstreet says it was driven by manufactures wanting a level playing field.
"Many manufacturers were frustrated by inconsistent, unreliable and unsubstantiated claims made about the 'green' credentials of rival products. They wanted an industry recognised approach."
Manufacturers are getting onboard
As BIM becomes more widespread, demand for models of proprietary products will increase. Some manufacturers already provide BIM objects of their products for download from their websites.
Greenstreet says this trend is sure to increase as standards are addressed.
"Poorly modelled objects can cause serious problems if imported into an otherwise sound model. The lack of agreed standards on items such as shared parameters (properties) associated with objects means they are not easily searched, sorted and scheduled. For example, window objects with different shared parameters will not schedule properly," he says.
"Without the clarity standards provide, manufacturers cannot be sure that models of their products they create will be widely accepted or useable. Also, the need to have their items modelled separately in different file formats to suit each BIM authoring platform multiplies the cost."
BIM's not just for the big projects
The availability of object libraries will encourage architects and designers working on smaller scale projects to adopt the technology.
At present, the benefits of BIM are better realised on complex buildings with numerous building services, such as hospitals. The early adopters of BIM have tended to do this sort of work and had the resources required.
The incentive is currently not great for those working on smaller projects like individual houses to move from 2D or 3D CAD to BIM.
Greenstreet explains: "One of the most helpful developments to assist those working on smaller projects would be the availability of object libraries with a lot of free local content. This would save the considerable time and effort they have to invest in creating the many common construction elements, fittings and equipment required to build most models. Currently, this effort is duplicated in many individual offices. Most designers would much prefer to be designing than modelling building products from scratch."
Perey agrees, "in the future, we can imagine that these software applications and skills will be commonplace: When that happens, even the smallest projects can benefit from using the techniques. And already project home builders use BIM to visualise the designs for their clients, and then produce schedules and materials lists. We will see more and more of it on small bespoke projects, and most graduates and younger architects have already had some exposure to BIM software and methods."
NATSPEC has noted an increase in the percentage of offices using BIM authoring software between 2008 and 2011, with 55 per cent of subscribers surveyed in 2011 saying they will be using BIM in the next 12 months.
The National BIM Roadmap considers NATSPEC to be the natural choice to act as host librarian for the objects. The not-for-profit organisation's focus centres on the provision of reliable, impartial and up-to-date information, much of which could be linked to models.
There are many other initiatives aimed at addressing the BIM challenges, both locally and internationally. A good place to find links is www.natspec.com.au.
Image: BIM - Derived photomontage visualisations of 100 Mount Street in North Sydney by Architectus