3D to 6D BIM
BIM dimensions refer to the particular way in which particular kinds of data are linked to information models. By adding additional dimensions of data a fuller understanding of construction projects is generated – its delivery, cost, maintenance etc. 4D, 5D and 6D BIM can all feasibly (but not necessarily) occur within a BIM Level 2 workflow.
This article will explore the different dimensions of information added to a BIM process and explore practical applications and expected benefits.
3D (THE SHARED INFORMATION MODEL)
3D BIM is perhaps the most widely-known form of BIM – the process of creating graphical and non-graphical information and sharing this information in a Common Data Environment (CDE).
As the project lifecycle progresses this information becomes more detailed until the point at which the project data is handed over to a client upon completion.
4D (Construction Sequencing)
4D BIM adds an extra dimension of scheduling data information to a project information model which is added to components, building detail as the project progresses. This information can be used to obtain accurate program information and visualisations showing a project’s sequential development.
Time-related information for a particular element might include information on:
- Lead time
- How long it takes to install/construct
- The time needed to become operational/ harden/cure
- The sequence in which components should be installed
- Dependencies on other areas of the project
With time information federated in shared information model, planners should develop an accurate project programme. By linking the data, the graphical representation of components/systems and project information queries become easy to understand. It is also possible to show sequential construction development, over time showing each stage of a structure’s visual appearance.
This process is enormously helpful when it comes to planning work through ensuring safe, logical and efficient sequences. Prototyping ability showing assets come together before ground is broken on site allows for feedback at early stages and avoids wasteful and costly on-site design co-ordination and rework. Construction project’s visual representation is handy during stakeholder engagement, ensuring everyone has a clear visual understanding of planned works and what the finished construction will look like with no surprises.
Adding sequencing information can be extremely useful, not just in the design phase, but earlier too, allowing schemes feasibility assessment from the beginning. At tender stage this kind of information allows initial concepts exploration and communication inspiring confidence in the team’s ability to meet the brief.
4D information does not negate the need for planners who remain an integral part of the project team. Creating a digital workflow allows planners to influence and shape proposals from a much earlier stage of a project – contrary to traditional methods of creating programmes as proposals develop. A significant increase in value can be added to a project by establishing a closer connection to the wider project team and providing feedback earlier in the process.
5D (Cost)
Drawing on information model components ablities to extract accurate cost information is at the heart of 5D BIM. Considerations might include:
- Capital costs (purchasing and installing components)
- Associated running costs
- Renewal/replacement cost
Data and associated information linked to particular components within the graphical model calculations can be made, allowing easy quantity extrapolation to quantities of given components on projects by cost managers. Applying rates to those quantities, thus reaches an overall development cost, which entails benefits such as:
- The ability to easily see costs in 3D form
- Get notifications when changes are made
- Automatic counting of components/systems attached to projects
Predicted and actual spend can be easily tracked over the course of a project by assuming the presence of 4D programme data and a clear understanding of a contract’s value. Allowing for regular cost reporting and budgeting ensuring realised efficiencies and the project itself to stay within budget tolerances.
Cost calculation accuracy is, reliant on data produced by multiple teams and shared within the Common Data Environment. Quantity surveyors and estimators therefore still have an important role to play, not only in checking the accuracy of information but also in helping to interpret and fill information ‘gaps’. Many project elements will still be modelled in 2D or not at all. The cost manager will need to clarify and understand the commonality between model classifications – which at first feel unrelated.
An information model is likely to contain three types of quantity:
- Quantities based on actual model components
- Visible details (explored through the model)
- Quantities may also be derived from model components
- (mouldings around windows) that are not always visible
- Non-modelled quantities
- (including temporary works, construction joints etc.)
Only if the construction phase is modelled first, followed by model design, these quantities will show graphically, but not the construction quantities. A cost manager is likely to be skilled in picking up the quantities that aren’t solely based on model components.
One of the advantages of cost extrapolation from the information model is that the data can be queried at any time during a project and the information that feeds cost reports is regularly updated. This ‘living’ cost plan helps teams design to budget and due to cost managers’ early engagement in a project allows for faster, more accurate cost reporting at early stages of a project.
The cost manager may have to get used to working earlier and more iteratively than in a traditional process but has just as important a role to play in overall project delivery.
6D BIM (Project Lifecycle Information)
The construction industry has traditionally been focussed on upfront capital costs of construction. Shifting this focus to better understand the whole-life cost of assets, where most money is proportionately spent, should make for better decisions upfront in terms of both cost and sustainability. This is where 6D BIM comes in.
Sometimes referred to as integrated BIM or iBIM, 6D BIM involves the inclusion of information to support facilities management and operation to drive better business outcomes.
This data usually includes additional component information such as:
- Details on manufacturers
- Installation dates
- Required maintenance
- Details on configuration and operation for:
- Optimal performance
- Energy performance
- Lifespan and decommissioning data
Adding this level of detail to information models allows decisions to be made during the design process – a boiler with a lifespan of 5 years could be substituted with one expected to last 10, for example, if it makes economic or operational sense to do so.
In effect, designers can explore a whole range of permutations across the lifecycle of as built assets and quickly get an understanding of impacts including costs. However, it is at handover, that this kind of information really adds value as it is passed on to the end-user:
Models offer easily-accessible and understood ways of extrapolating information. Details that would have been hidden in paper files are now easily integrated graphically. Facilities managers are enabled to pre-plan maintenance activities potentially years in advance and develop spending profiles over the lifetime of a built asset, working out when repairs become uneconomical or existing systems inefficient. This planned and pro-active approach offers significant benefits over a more reactive one – not least in terms of costs.
Ideally the information model should continue to develop during the In-Use phase with updates on repairs and replacements added in. Better yet, a myriad of operational data and diagnostics can also be fed in to inform decision making still further.
