“Why 4D Planning is the Only Smart Way to Plan a Project."
-By Pipetech | Published on April 3, 2021
4D planning One of the flagships uses of BIM and digital mock-ups in the
construction industry is the ability to “build before building”, materialized by what is
now called 4D planning.
This use alone carries a large part of the interest that construction companies have in
By its nature, it offers both a strong commercial valuation of the offers given to a
client but also a marked improvement in the precision of the planning of the work, in
particular as regards the interface between the various trades.
General definition The planning term “4D”, like 4 dimensions, leaves however
dubious at first glance:
What does this fourth dimension designate in three-dimensional space such as ours?
The translated point gives a segment, a translated segment gives a square, a translated
square gives a cube, a translated cube gives a tesseract (or hypercube)
You are well advanced, right?
The fourth dimension represents the time which is part of the space-time frame of
reference This is already much closer to what the term 4D planning designates.
Definition for construction It is therefore a matter of having a 3D model (digital
model) and adding an additional dimension to it: time.
Behind this term, which takes on an image of “science fiction”, therefore hides an
essential response to site management.
Traditional planning makes it possible to answer the question
"Who does what when?"
A 4D schedule helps answer the question "who does what when and where?". It is
therefore in other words a phasing applied to a digital model.
This type of document cannot, therefore, be viewed in the form of a single paper
document but must be viewed either in the form of a video, in the form of a printed
notebook by defining the sequence of “key phases” of the project.
Viewable on a computer using software that overlays a 3D model.
What is 4D?
In a BIM environment, there is regular talk of a 4D model. In principle, it is a
generally accepted name to indicate that besides the geometric aspects, there are also
other parameters taken into account in the model.
We no longer speak of “dimensions”, but of “domains”.
In most cases, 4D has been taken into account as well as planning, in other words: the
“time” aspect as the fourth dimension.
This goes a little further than a three-dimensional BIM model, to which a lot of
information is already linked. In principle, a schedule is established for each project.
However, it is only as soon as it is linked to the model that we actually speak of
modeling or 4D visualization. BIM model as a planning tool
Some architects are currently adapting to 4D by creating BIM models where the
phasing is detailed virtually.
This can relate to an existing state with parts to be demolished, in combination with
the new extension in the same virtual model.
In addition, some entrepreneurs run pilot projects where they want to extract their
planning as much as possible from the BIM model.
We can already, at an early stage of the project, make a rough schedule associated
with larger volumes/elements.
It is then used, for example, during design to give the owner a better vision of the
project, well before it comes to execution.
Another example is the negotiation with an urban planning department, to clarify the
impact of the traffic of a large building site, or to illustrate the major phases - for
example also during information campaigns for the population in large public projects.
At run time, however, the schedule will be much more detailed and therefore, usually, detailed information does not arrive until the model reaches LOD300.
In this way, the items are also detailed by the contractor in the correct order and
passed from a LOD300 to a LOD400.
It is then up to the contractor to maintain good communication with designers and
subcontractors to keep the schedule fully up to date.
Planning costs One of the big advantages for many parties is that the expenses they
incur are easily linked to the planning.
Take the obvious example of the entrepreneur.
It can make a much more precise estimate at the start of the run. From there, he can
carry out a financial analysis in advance which is useful for all parties, including the
For example, a contractor can estimate how many tonnes to supply the concrete
batching plant per unit of time and include this in the model to forecast optimal
If this is done with deliveries from all producers and subcontractors involved in the
implementation, optimization can take place in the area of logistics and storage.
Obvious added value A 4D model is, in other words, beneficial at all stages of
construction, but above all provides significant added value during the execution of a
For designers - architects and engineers - there is no particularly important difference
between working with a 3D or 4D model.
It takes more time and effort to get some sort of correct phasing in the model, but of
course, it gives additional communication possibilities.
The most important thing is that the whole process is more dynamic and generates
less risk, possible delays, or unnecessary costs.
What do we mean by 4D planning?
It is a sequence of images in video format or in the form of extracts highlighting the
key dates of construction.
4D planning is based on a 3D model, that is to say, that at time T, it is possible to
visualize the site thanks to a three-dimensional projection.
But to arrive at the concept of 4D, the additional dimension of time enters into the
4D planning procedure To carry out 4D planning, the digital BIM model is essential. It forms the basis on which stakeholders work.
The data gathered there provides information on several parameters such as the type
of structure, the number of floors, etc.
Once the model is in hand, the intervention objects must be filtered. The model must
represent all the works to be treated, and this exclusively.
After filtering, you might need to make some modifications to the model.
Indeed, as the modeling was carried out by the architect, it does not necessarily follow
the necessary constructive logic.
If the facade is drawn in a single element from the foundation to the roof, it is
necessary to cut it in stages.
The preparation of the traditional planning follows this step. It consists of organizing
resources and smoothing out the pace in order to optimize the site.
The schedule is then compiled using 4D planning software. At this point, you can
import both the BIM model as well as your planning.
The last step is to link the works to the tasks in your schedule. This makes it possible
to integrate the Time dimension into the three-dimensional digital model.
After all these series of actions, the software can launch the video or the sequence of
extracts of the construction.
Why use 4D planning?
The interest of 4D planning spans several levels, whether technical, commercial, or
Technical advantages This planning facilitates dialogue between the various
stakeholders on the site.
The workers then grasp any sources of conflict and confusion in time.
The 4D schedule optimizes the organization of the site. For example, you can
accurately predict the poured concrete at Construction supervisors can easily consult
this data on the date in question to order the necessary materials.
Commercial advantages Providing a significant visual impact, 4D planning is a
commercial tool facilitating the persuasion of customers.
Security advantages Carrying out a 4D schedule makes it possible to understand the
intentions of the workers even before the start of work.
Thus, the coordinator can issue opinions and correct risky situations in advance.
BIM 4D: what is it and how to assign the property "time" to
an object of the BIM model BIM 4D: together we discover how
thanks to a powerful tool,
It thus facilitates collaboration between the various stakeholders involved in the
various phases of the life cycle of a structure.
The BIM 4D adds additional information to the model may provide the professional
tools useful to him to optimize the planning and project management and execution of
The fourth dimension of BIM (BIM 4D) makes it possible to analyze and evaluate
In this way, designers can coordinate the different subjects and plan the activities
correlated with the construction process.
4D modeling allows designers to visualize the progress of activities already in the
design phase in order to obtain significant benefits such as verification and
optimization of work execution time checking critical overlays assessments of
different possible scenarios.
In this way, it is possible to visualize the entire construction process by means of a
calendar and, therefore, to optimize the times.
This allows the 4D management of a BIM project allowing to define temporal
information directly on the BIM objects of the project It should be noted how this
solution is easy to use.
The environment is presented with a simple and intuitive interface.
In a very simple and intuitive way, we can create our structure by adding activity and
defining a title (we can define a start date or a duration.
it is possible to break down the project into elementary parts (periods) and to connect
them to the objects of the model via the Drag & Drop function.
We can associate objects of the same group, link a single object or objects belonging
to different types.