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3rd Dimension

A 3D BIM model contains 3D objects that builds up the information model. These objects represent the building or buildings spaces, in a virtual reality. These 3D objects contain information, as a minimum, on length, width and height. Other information can be applied, such as material and finish. Key benefits of a 3D information model are improved coordination, enabled visualization and general information gathering. 3D modelling requires 3D modelling software and LOD definition.

4th Dimension – Time

The 4th dimension refers to adding time to the 3D, often called 4D modelling or model-based scheduling. This is done by linking objects from the 3D model to a task in the construction schedule, using a 4D scheduling tool like Vico Office21, Synchro22 or Navisworks23. This approach is changing how complex projects are planned, making it possible to visualize the whole construction project or just some phases of it, and see who timing of tasks affect the workflow. This includes comparison of planned versus actual schedules; time-based clashes, such as verifying the planned sequence towards constrained activities (i.e., demolition, permanent construction and temporary construction), site utilization planning and more.

A 4D model can be used at all stages of the project. During the conceptual design, it can be used to discuss site logistics. During the construction phase it can be used to validate costs of completed work, demonstrate work to owners, provide health and safety instructions and justify subcontractor billings to the owner for completed work. Once a 4D schedule is setup, it requires little work to maintain and update.

5th Dimension – Cost

5D modelling or model-based estimating is the 4D model in addition to cost information. A model-based schedule or 4D schedule is associated with information on cost, which allows the owner to know the exact amount the contractor should be billing at a given time. Over the past years the method has been redefined, where the 5D estimations is done in the form of a take-off, where the model is used to extract quantities of materials and associate costs with those materials for estimating purposes. It should be noted that the model cannot provide accurate estimates until LOD has been properly defined. Experienced personnel in both technology and in cost estimation are required to achieve success in applying the 5th dimension.

6th Dimension – Facilities Management

The 6th dimension is devoted to Facilities Management and focuses on leveraging the model information to reduce owners’ cost over the life cycle of the building or structure. Sometimes 6D BIM models are referred to as Asset Information Models (AIM).

A 6D model does not necessarily contain all the information from previous dimensions. Over the design and construction phase, information for the operation of the facility is gathered. The model should contain information on the colour of a wall, types of doors, frequency of maintenance on the roofing felt, type of light bulbs etc., but size of reinforcing bars is generally not necessary. Time and cost are included, but the objective here is to gather information on frequency of maintenance and analysing the operational cost.

Information for facilities management is often gathered by using an information exchange standard, Construction Operations Building Information Exchange (COBie), developed by National Institute of Building Sciences. The aim is to deliver asset data a distinct entity from geometric information


The BIM Team at Wills Bros have expertise to work and develop 4D and 5D project BIM Models. We as a progressive and onward looking organisation aim to move to 6D as the industry progresses and matures in 6D further.

Wills Bros has the designated trained experts, deign authoring software, scheduling software, 4D modelling software and IT infrastructure to cater to such needs for our clients in the AEC industry.