It can be easy to get your 2D, 3D, 4D and 5Ds mixed up with your BIM Levels 0, 1, 2 and 3 so I have tried to give an explanation of where everything BIM sites and at the end an explanation of where they all fit together.
Nobody really explains what the levels are but everyone talks about it, tells you their opinion about it or has an opinion about it in construction. Here is a simplified take on BIM and the D’s.
Level 0 is defined as unmanaged CAD. This is likely to be 2D, with information being shared by traditional paper drawings or digitally via PDF. This can be seen as separate sources of information covering basic construction information.
Level 1 is a mix of 2D and 3D design information using BS1192 with a collaboration tool providing a Common Data Environment (CDE). This CDE may be a web based database which can be connected anywhere.
Level 2 is a collaborative BIM. Here you get your federated model and information is shared within the Common Data Environment. This CDE may again be a web based database which can be connected anywhere but sharing is done within the environment. The method of naming is usually specific and to a set standard.
Level 3 is very much an aspirational and visionary and is an integrated solution around open standards such as IFC with everyone working from a single model stored somewhere in a web service or cloud. IFC is a platform neutral, open file format specification that is not controlled by a single vendor or group of vendors.
The Levels of D…..
2D – The plans on the desk from blue prints to photocopies showing are 2D as is 2D CAD. This is the bottom level and what we used to draft in with pen, ink and stencil. The level should never be forgotten. It is how we sketch, how we draw illustrative details and a reliable and dependable function.
3D designing with 3D Drawings, Safety Models and Logistics Models with BIM driven field layouts, animations, renderings and walkthrough’s all come together to form what is essentially 3D.
4D Scheduling time, phasing and planning with lean scheduling for just in time deliveries and a detailed simulation. There are pieces of software that link programme to model. This is gaining traction within the industry to give construction in 3D linked to a programme on a computer screen.
5D Estimating with real time cost modelling and quantity extraction to support detailed cost estimates with trade valuations fulled linked between 3D and 4D areas.
6D Management and facilities management application with lifecycle BIM strategy, as-built, embedded O&M. There is also an argument the 6D may be Sustainability or even Carbon. Are we there yet, I would say “No”.
How the Levels 1, 2, 3…. link to 2D, 3D, 4D….
You can broadly place BIM Level 0 into the unmanaged 2D CAD Design. This is followed by BIM Level 1 where you get a mix of 2D and 3D design. BIM Level 2 links with 4D and 5D and is a mix of 2D and 3D design models, objects and collaboration with or within a Common Data Environment along with a federated model. BIM Level 3 is all of this and more linked neatly with 6D. For clarity I think we are not BIM Level 3 in the UK and that nobody is level three. There are multiple parts to become BIM Level 3 compliant and really nobody knows what it fully entails. BIM Level 3 is an aspiration that is unlikely to happen in the next 5-10 years.