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  • The government’s definition of the various levels of BIM

BIM for landscape

BY RUTH SLAVID, Editor
The Landscape Institute is progressing fast on producing information that will allow landscape architects to participate in the BIM revolution. It advises practitioners to be alert, to learn and listen — and not to be bullied into buying unsuitable software.

When the Landscape Institute set out to raise awareness across the profession about BIM (Building Information Modelling), it quickly discovered a pleasing level of knowledge, or at least awareness, of the issues. ‘At our first BIM event in September,’ explained chief executive Alastair McCapra, ‘we thought we would be doing a roundtable answering the question “What is BIM?”. But we soon found that the level of awareness was well beyond that.’

Instead, landscape architects were asking more informed questions, in particular asking how they should respond to contractors who said to them that if they wanted to be BIM-ready they should buy specific software packages — most frequently Autodesk’s Revit. It was this that led McCapra to respond with the injunction ‘Be prepared but buy nothing’. The institute has also issued a guidance note (http://bit.ly/VdFnuu ) for practices, both outlining some of the terms that constitute BIM, and reiterating the advice not to be rushed into unsuitable purchases.

The reasons for this are twofold. Traditional CAD software has not served landscape architects well, and buying 3D versions of this, suitable for working on shared models, will not help. And, crucially, BIM does not require the use either of 3D software or of specific packages. Instead it is about sharing information, and the way that the information is to be shared is through a format known as COBie, essentially an Excel spreadsheet into which participants in a project will enter and share relevant data.

This is the format that the government has decreed that it wants for the adoption of BIM in its projects. It has said that all government-funded projects must be executed in Level 2 BIM by 2016. Level 2 essentially means that participants in a project exchange information in an approved format, and that format will, it has been decided, be COBie. By having a protocol in place, there should be no double working, contractors on site should have all the requisite information, and at the completion of the project the information can be handed over to those responsible for maintenance. BIM is in fact about the sharing of knowledge and about communication, not about the adoption of a particular computer technology. It is true that the next level, Level 3 BIM, does require the team to work on a single building model, but there are many BIM experts who believe that achieving that is still a long way off.

This was stressed at a meeting of the Government’s BIM Task Force in the autumn where the message came through clearly that, as McCapra paraphrased it, ‘The age of the big shiny model is over’. Speakers emphasised that the whole point of COBie is that it liberates data from the model and that for many assets there will never be a ‘model’ in the sense that software vendors use.

If this sounds however as if the Landscape Institute has decided that there is nothing that needs to be done, and nothing to worry about, this could not be further from the truth. The institute’s BIM working group has been working hard on ensuring that COBie covers landscape. Just as CAD packages that work for much of construction are not appropriate to landscape, so the work that is being done to develop COBie for the construction process will not be appropriate to much landscape work — in particular to soft landscape. The working group is therefore developing templates for data to be included within COBie.

This builds on work that has already been done on the National Plant Specification (NPS). The NPS is already partially BIM-ready since it provides a standard format for the procurement and specification of planting material. It needs to be expanded for BIM, particularly to provide information on maintenance and management, since the government defines BIM as ‘creating, managing and sharing of the properties of an asset throughout its lifecycle’.

Tim Calnan of CS Design Software, who is on the BIM working group, believes that COBie is an interim position and the future of BIM will be the Industry Foundation Class (IFC) data model as a deliverable. Like 3D models, which have been discussed for over a decade but are only finding wider use now, the concept of an IFC data model is not a new idea. The principle of this approach is relatively simple. It is a data schema comprising information covering the many disciplines that contribute to a building or space throughout its lifecycle: from conception, through design, construction and operation to refurbishment or demolition. The model consists of objects which hold the information about not only their physical appearance and properties but also their anticipated lifespan, their mainetenance requirements and their method of disposal.

The challenge of an IFC data model approach is similar to the challenge of COBie — how to avoid including too much data. In the case of COBie this would result in spreadsheets that are so long and demanding that nobody would have the ability or the will to fill them in. With IFC data models, the problem would be that the amount of information contained in a model built up from detailed objects would be so great that the model could only be manipulated on the most powerful computers.

Still these are problems that will be overcome because they have to be overcome. And one can then imagine plant objects being available to import into IFC data models. (If there is an emphasis on the soft landscape elements in the Landscape Institute’s work this is because these are the ones that are least likely to be covered by architectural or engineering design packages).

The National Plant Specification is an excellent tool in terms of setting the parameters that need to be covered but it is very restricted, for historic reasons, in terms of the number of plant species that it covers. It would therefore produce a very limited palette if its data were to be translated. Calnan believes that additional information will be required, perhaps from a range of sources to ensure an appropriate palette of planting backed up by reliable data on plant requirements, maintenance, and even cost and availability.

That is for the future however. At present, the main focus is on producing the templates for inclusion in the COBie spreadsheet, consulting on them and disseminating the results. At the same time, the Institute will continue to run workshops. It is eager to find examples of practices that are working with BIM already. If you are involved in a BIM project and can share insight or have some particular concerns, or if you are having particular issues raised by clients, then please contact the institute’s head of IT Jim Riches on [email protected]

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