Intimidated at parties by your peers' ability to converse freely about object specification and interoperability? Perhaps you're going to the wrong parties. But don't panic – this clear and simple guide will have even the technophobes cornering each other for in-depth chats.
Interoperability. Industry Foundation classes. Object orientation. The terminology is hardly self-explanatory. Unfortunately, what it refers to – object technology – is probably the most important advance in design since it became computer-aided, which means that at some point you will need to bluff your way through a conversation on its merits. Here's how to do it.

What is an object?

Traditionally, architects have designed buildings on paper, using lines that represent parts of the building, such as doors, windows and pipework.

An object is much more than this. Rather than being just a set of lines, it is much closer to the thing itself, constructed by computer software. For example, a door "knows" how tall and how wide it is, how much it weighs, what it is made of and how much it sells for. It also understands how it relates to the surrounding wall. Put it in a frame that is too small and it will tell you it does not fit. Similarly, a light switch on the wrong side of the door will take itself to the right side as soon as it realises something is up.

What is object modelling?

This is the process of piecing together all the objects to create a model of a building. Object modelling closely simulates real life. In the same way that two pipes cannot pass through each other in a real building, their object counterparts in a CAD drawing alert you if they are being asked to do something impossible. The program will also tell you if the pipework clashes with ductwork or light fittings.

Why is this useful?

By building an object model, the designer creates a simulation of the building. This means mistakes can be rectified before construction work starts. This can prevent niggling design faults, for example, light switches on the wrong side of a door. It can also prevent larger, more expensive problems, such as pipework that does not fit.

The potential for waste reduction is enormous, particularly considering the number of errors that can arise during the transition from concept to implementation, in which the engineer interprets an architect's drawings and the contractor makes sense of those drawings on site.

Sounds fantastic. So, why isn't it fitted as standard?

The main obstacle to the use of object models is the lack of a common language among software applications. There has to be a means of ensuring that an object behaves exactly the same way in a MicroStation CAD system as it does in an Autodesk CAD system. For object modelling to work fully, objects must also behave the same in any relevant application.

How can that be done?

The International Alliance for Interoperability is working to draw up a database of object specifications that can be shared in different software applications. The UK chapter, as the alliance's branches are known, includes members from BAA, Buro Happold, Laing and London Underground. It also includes software outfits Bentley Systems and Autodesk. The IAI is drawing up industry foundation classes for objects to ensure that they behave in the same way in as many software applications as possible.

What is an industry foundation class?

The IFC is the definition of an object. Each object has certain attributes: height, width, material and price. The IFC creates the standard data that can be recognised by any software application.

Come again?

Think of it like this: a telephone conversation will remain the same regardless of which telephone you use to make a call. Change from a land-line to a mobile and you don't find yourself speaking French. Similarly, with object modelling, a door object is the same if you transfer it from AutoCAD to MicroStation. How MicroStation goes about interpreting an object's specifications is irrelevant; it is only relevant that it can. The IFCs allow that information to be shared. This is otherwise known as interoperability.

Another long word. What does it mean?

The ability to operate between systems in a common way. IFCs aim to make interoperability possible across as many software applications as possible.

So, when will we all be using it?

Nobody knows for sure. The IAI is looking for demonstration projects to be used as case studies to educate the industry. Consultant WSP Fulcrum is already using object modelling on M&E packages and Laing is fully behind the potential of object technology; area manager Brian Zelly is chairman of the IAI. Laing has already done some work on the use of object technology and is thought to be looking for a major project to carry out more extensive work.


Andy Ling associate director at WSP Fulcrum Dave Bloomfield technical director at the Building Research Establishment’s centre for IT Jeffrey Wix, director, Jeffrey Wix Consulting The International Alliance for Interoperability