4D – Scheduler or Modeler?

When someone talks about 4D, the discussion always seems to turn to who should be responsible. I have tried to think of job tasks that are truly a combination of two separate, and somewhat difficult, areas of skill and expertise; I can’t seem to think of any that come close to the 4D dilemma.

Dilemma you say? Yes dilemma. 4D requires two very different skill sets. When we think of scheduling, Primavera, and sometimes MS Project, comes to mind. When we think of BIM / VDC we think of Autodesk, Navisworks and others.

What do these two very different and distinct skill sets have in common? Nothing! That is until they are married at a shotgun wedding to produce a 4D animation. Then that creates a bigger issue, who really is responsible to create, manage, update and own the 4D process? I contend it should be the scheduler working with the BIM / VDC experts to make it happen. The planner / scheduler can communicate how the model can be created to facilitate the plan.

For example, is the Slab on Grade going to be poured all at once or in 4 pours? Additionally, a 4D simulation at its heart, is a schedule that has tasks linked to turn on 3D model elements. 4D is simply taking scheduling to the next level of planning and communication. The modeler’s role is key and a huge part of it, but it really is up to the planner / scheduler to take the model and schedule and use it to better plan the project. Those schedulers stuck in the 2D world of Gantt charts and F9 are going to be left behind. Just as computer-aided drafting eliminated drafting by hand and iTunes has killed the brick and mortar record store, so will 4D scheduling change the way projects are won, planned, and monitored and will become the industry standard.


  1. These are definitely two completely different skills – model authoring, and schedule creation combining to create 4D models/animations. Historically, firms have split the two with architects designing and superintendents/specialists scheduling and the idea that both should be performed by one person results in a very small number of people who can actually do it as well as the question as to who remains responsible for the 4D after its inception.

    In addition – technical requirements for large scale 4D models and animations are extremely high. Running complete 4D models in a live atmosphere is arguably impossible and once we start developing animations to show sequencing in 4D we end up involving a third discipline – video editing.

    My preference – keep 4D animations basic and small, and applicable to field activities. Focus on the architectural model to show sequencing via color coding and do basic screenshots from complete coordination models with specific elements hidden to show the areas that are truly complex enough to require detailed 4D sequencing… or admit that what you are creating is for marketing only, and not for the benefit of the field.

  2. I agree in general with your assertion. In practice it depends on the scheduler. Many of them are very well versed in Primavera or MS Project and solid in their skill set of providing multi-filtered schedules for various needs.
    There are not as many, however, with much experience in using Navisworks or Solibre to created 4D models, plus many are very resistant to adding this to their list of responsibilities. In the ideal Design-Build world this would be a collaborative team made of a scheduler and modeler working from the beginning of the design process. The reality is that the contractor in a Design-Build often is kept at arm's length during much of the initial design stages and therefore has very little chance to direct the model creation so it works with a construction schedule. Where I work, we are trying to make this happen with so far limited success. It is a long road ahead. I believe that the design and construction world must adjust to this way of collaborating. I am a part of the #1 general contractor in the country for utilizing BIM in our projects and we still have to fight within our own project teams to get everyone on board with BIM, so the industry has a way to go. I am hopeful though. There is a strong commitment to it.
    I think metrics will be key to getting early connection between schedule – design – and BIM as a part of the standard. We have to have proof of the benefit to convince the upper management in some cases and educate the department heads at all levels to the benefits.

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