Monday, 29 January 2018

The Many Dimensions of BIM

In the design and construction industry, we talk a lot about Building Information Modeling (BIM) which is the process of creating a digital, information-based 3D model of a project. This could include buildings, factories, warehouses, infrastructure such as roads, bridges, mechanical services, structures, and much more.

As we progress with BIM, data becomes more important and a crucial element of the BIM and the project. We can utilize these model elements and information beyond the creation of construction drawings. Using this information, our models can go beyond simple 3D into 4D, 5D, 6D and even 7D.

3D: Modeling
3rd dimension (3D) modeling is the digital representation of the intended design or existing condition. The combination of digital model elements and associated information (data) used during the design phase can be included or associated with the model. These 3D models are used during the design process and facilitate coordination of all consultants’ design models and are also used for clash detection. For existing conditions, 3D BIM is a digital representation of the existing condition, a scan of a building, structure or site.

The model can be utilized for a variety of uses including visualization, early building performance analysis, sustainability evaluation, preliminary cost analysis and the generation of documentation (drawings). Collaboration, clash detection, and design review are all aspects associated with 3D.

4D: Time (Scheduling)
The 4th dimension associated with BIM is time and the management of time including construction sequencing and scheduling. 4D is typically used to show an intended time lapse of the construction schedule; linking model elements, assemblies, and data to a schedule.

For example: Construction sequence of concrete pours and the scheduled delivery of concrete based on the volume and location of the pours in a day.
Scheduled delivery of materials or trades.

5D: Cost (Quantification)
5D is the progression from 4D by combining the cost of the quantities and time. By linking model elements and assemblies along with the schedule (4D) to establish related costs, this model can be used to quantify materials and the cost of construction.

Model-based estimation of construction, estimating the capital costs including the cost of purchasing and installing components or assemblies. The 5D model can enable us to visualize the progress of construction activities and its related costs over time.

For example: Floor finishes based on the room area to quantify how floor finish volume can be used to calculate floor finish cost.
The cost of drywall based upon volume combined with the hourly rate of labor. 

6D: Performance
There is still some confusion in the industry regarding the exact definition of 6D and 7D, and they are often combined. 6D can be utilized for energy modeling and evaluating the proposed design for building performance. It can also be used to measure and validate estimated energy modeling against actual performance.

For example: Using sensors within the building to track building performance by monitoring heating and cooling levels.

7D: Facilities Maintenance and Management
Asset Information Model (AIM), using the BIM to maintain and manage the asset such as a building, equipment, structure, etc. Linking model attributes and data to support facilities management and operation. Used to manage the ongoing “life cycle” cost of the building.

Streamlines asset management over the life of the building and provides a database for ongoing tracking, maintenance and management.

For example: linking the maintenance schedule to a piece of equipment such as a cooling tower or heating pump.
Staff seating map for each floor, manage and track furniture (assets) within the building.

8D: Deconstruction
8D, which is rarely discussed or graphically represented and involves the building “afterlife,” the decommissioning, demolition, repurposing or recycling of a building or structure.

Utilizing the BIM we can understand how best to deconstruct the structure, what materials are involved (and even the quantities), or how best to repurpose the structure.

Graphic by The BIM Jedi


  1. Great post.
    As 6D and 7D confusion. There is another. I have read that the 8D is a BIM modelling tool for accident prevention through design.
    Also you could see 9D as a lean construction process.
    In conclusion. After 5D there is a lot to tell and work.

  2. Great comment, and your absolutely right. I love the idea of "accident prevention" as being integral to BIM utilization!