You might have heard the terms “4D Schedule Models”, “4D Scheduling”, “4D BIM”, “4D BIM Modelling”, “4D Simulation”, and “4D BIM Planning.”

For simplicity, let’s refer to these terms as “4D Scheduling”.

But, what do we mean by “4D Scheduling”?

What is 4D Scheduling?

4D Scheduling is simulating the planning sequence of construction activities and space requirements on a 3D model.

4D adds the time factor of the construction schedule to the 3D model.

In simple terms, 4D scheduling is the “visualization of the construction schedule.” [2] That’s it!

To further explore how 4D Scheduling differs from traditional scheduling, please check this post. 

Types of the 4D Schedule Models

1-  Standalone 4D Schedule Models

The first type of the 4D Schedule Models is the “standalone 4D schedule model.”

In this model, there is one 3D model and one schedule. When you link each task in the schedule with the corresponding element in the 3D model, you’ll have a single standalone 4D schedule model.

2-  Comparative 4D Schedule Models

Another type of the 4D Schedule Models is the “Comparative 4D Schedule Models.”

Comparative 4D models allow the project team to simultaneously review multiple yet related 4D models and visualize multiple scenarios.

For example, a comparative 4D schedule model could be a scenario that allows the user to perform a visual comparison of a single 3D model and two schedules. This scenario uses one 3D model that is linked to two schedules.

Comparative 4D Schedule Models- Scenario #1: (One 3D Model and 2 Schedules) [1]

An example of this comparative 4D schedule model would be visually comparing the “baseline schedule” with the “updated schedule.”

This type of comparative 4D model is also used in schedule delay analysis that involves the comparison of schedules, such as an as-planned schedule versus an as-built schedule.

Another scenario for the Comparative 4D Schedule Models is the visual comparison of two 3D models and their corresponding schedules.

Comparative 4D Schedule Models- Scenario #2: (Two 3D Models and 2 Schedules) [1]

This type of comparative 4D model is well suited for performing “what-if” schedule comparisons, especially when you experience some potential scope growth or design changes.

Similar to the first scenario, this scenario is beneficial for use in schedule delay analyses that involve the comparison of schedules, such as an unimpacted schedule versus an impacted schedule.

To get more information on the 4D Schedule Models, check the video below presented by Tamer Elgohari at the 2020 Project Control Summit.

Note: This video is a sneak peek of the presentation on “4D Planning integration with new technologies”, presented by Tamer Elgohariat at the 2020 Project Control Summit. 

To get access to the full presentation and other recordings of the Project Control Summit, please click here.

In Summary:

4D scheduling is the “visualization of the construction schedule”, which is achieved by linking a 3D digital model with time or schedule-related information.

The visualization of the 4D schedule models can take various forms, depending on whether you are comparing one or more related 4D models and schedules.

Resources:

• [1] 2008 AACE INTERNATIONAL TRANSACTIONS, Leveraging the Power of 4D Models for Analyzing and Presenting CPM Schedule Delay Analyses, by Mr. Kevin Coyne, PE PSP
• [2] 2020 Project Control Summit, 4D Planning integration with new technologies, by Tamer Elgohari
• 4D Scheduling vs. Traditional Scheduling (Which one do you prefer?)
• The upcoming Project Control Summit; the Best-in-Class Global Virtual Conference in Project Controls

About the Editor, Shohreh Ghorbani

About the Presenter, Tamer Elgohari