BIM: THE BASICS
BIM (Building Information Modelling) is an inclusive and simple process, providing 3D modelling of products of all shapes and sizes. It is common to hear of a ‘BIM Workflow’ – BIM objects focus on sharing digital information about the object – they are useful the whole way along the chain, and often provide maintenance, sustainability and resource information, and even manuals and asset management information for ongoing use once the project is complete.
These objects can be provided by the manufacturer for a specific product, or be a generic model for the item. BIM objects can be made for lighting and furniture, entire buildings and mechanical structures, and everything in between, and contain information about the product.
By creating a design using BIM, the specification is auto-generated, and often the objects have an ‘array’ feature – for example, the Gartec Platform Lift BIM Objects have a variable number of floors, which you can set to alter the object within your drawing.
The completed model also uses ‘Parametric Modelling’ – which means when you change the length of a wall, all the quantities and products required are updated in the specification.
THE 7 D’S OF BIM
The various elements held within a BIM Object are detailed below. All the information being included allows for scenario planning and what-if analysis, as well as optimising the project.
- 3D: the normal 3D we all love and know
- 4D: Time – scheduling information within the object
- 5D: Cost – the approximate costs for planning
- 6D: Sustainability – energy analysis and environmental information for optimisation
- 7D: Maintenance – ongoing product operation and maintenance information
BIM objects are designed to make it easy for specification, with objects provided in a variety of formats to use in almost all drawing types.
There are a number of software providers that have a platform for BIM. We’ve listed the top ones below, but it’s mostly down to preference and cost:
- Autodesk: Revit
- Graphisoft: ArchiCAD
- Nemetschek: Vectorworks
- Bentley Architecture: AECOsim
- FreeCAD (basic CAD software which includes a BIM module)
There are hundreds of BIM libraries out there, and many companies create their own to promote their objects. In amongst the noise, there are a few major BIM libraries to pick from which set high standards and generally provide first class objects for free, in a range of formats including IFC, ARCHICAD, Revit and Vectorworks.
The first is the award-winning NBS National BIM Library, which is owned by RIBA. The NBS have very high standards to promote quality and consistency. The site also has downloadable plugins to allow you to directly drag and drop into your drawings, and offers some generic objects.
BIM Store is another major player which has a desktop app to make it easier to get objects fast. BIMstore also features BIMWorld, where wacky creations lie – including an AT-AT from Star Wars, and a Fender guitar!
The final big one is BIMObject, which offers an app which enables instant downloads within your software. They also promote their use of ‘BIMobject Properties’ which reduces the size of a file and allows you to retain only the useful or relevant data to your project (e.g. language, country-specific regulations).
Whilst the libraries are all very similar, the tie between RIBA and NBS National BIM Library make this the provider of choice for around 42% of architects*. If you can’t find a manufacturer object on one site, it may be worth checking the others.
BIM IMPLEMENTATION LEVELS
There are different maturity levels of BIM knowledge/use. Level 2 is currently the requirement for public government projects, and level 3 is yet to be implemented.
- Level 0: basic 2D CAD drawings using lines
- Level 1: CAD for 2D & 3D models without model sharing
- Level 2: collaborative 3D environment, data attached
- Level 3: TBC – single collaborative online modelling by full chain with all 7 D’s in use
For more detailed explanations, please see the NBS website.
BENEFITS OF BIM
Gartec’s top 10 reasons to use BIM:
- In 5 years’ time, 97% of architects are going to be using BIM*
- Reducing conflicts using parametric modelling
- Improving collaboration and information sharing
- Long term cost reduction
- High quality, accurate 3D+ plans
- Reduction of ‘re-work’ between groups
- Fly throughs and simulations mean better understanding
- Free to download and use
- All public government projects require BIM
- Huge amount of support available