BIModeling: Why?

BIModeling: Why?


Environmental sustainability has lately become one of the most relevant issues analysed in our society, together with public debt, anti-seismic safety measures, the rehabilitation of degraded urban areas, etc.  Therefore, building and refurbishing projects always become more complicated with time. Consequently, professional roles gradually become more specialised.  On one hand this permits an improvement in the overall quality of projects, but on the other hand it leads to an increase in the number of professionals needed for a project to be completed and a consequential fragmentation of the industry.

Translating the information for an entire project into a digital form, using the same standards and language, enables it to be managed more easily, and improves the individual work and general communication between each member of the project team.  We call this process “using the BIM”.

Good collaboration should always start with putting the final aim of the project as the number one priority, permitting the optimisation of the work of others by passing on information efficiently without losing the focus on this goal.  Therefore, when starting a new project the first questions to ask should be: “What information will facilitate my work? What information will simplify the work of others? What information will make the final user satisfied?” We are the final user.  When we enter an office, a school, or an airport we want to find a comfortable, functional, and non-polluting environment that is well kept and safe.

The users are represented by the client who commissions a building that must correspond to certain requirements of building usage, aesthetics, services, cost efficiencies, environmental impact, etc. The building is drafted, designed in more detail, then built until it reaches its final status. After that point it must to be maintained, always keeping in mind that the user will be the one who benefits from the result.

The BIM facilitates the exchange of information and data between one step and another during the life of the project.  Because the information is standardised and checked, it requires no further verification or re-writing.  Having reliable data allows for the making of optimised decisions.   Given its digital nature, one can take advantage of the use of sophisticated software and increase productivity, greatly reducing the time consumed.

The value of information exchanged during the project life: BIM vs traditional.


The revolution of the BIM lies in the concept that the work produced by each individual has to be useful and easily readable by whoever will come next. For this purpose, the information needs to be standardised and recorded in a language that is understandable by everybody.   How does this translate into practice?

Four points need to be considered:

  • How to structure the information?
  • How to make it understandable?
  • Who needs the information?
  • For what reason?

The first two points were analysed in the article ‘BIModel’.  To answer the last two questions one needs to look at the entire life cycle of the project. This could be broken down into five phases:

  1. Identification of the requirements
  2. Project design
  3. Construction
  4. Use
  5. Demolition

The majority of the information is developed during the first phases (project design and construction). During the last two phases the data is more difficult to recover, when it would be more useful during the use phase and for the demolition. One must consider that the life cycle of a standard building could be from 50 to 70 years. During this period of time the contracting authority will have to search for the needed data (EIR) and the other professional roles will have to do the same.

From an economical point of view, it is during the initial steps of project design that the costs of the rest of the building life cycle is decided. For this reason, it is crucial that the information produced in the initial stages is precise and recorded correctly, in order to save money, time and resources during the final phases. It is during the BIModeling phase, therefore, that the most crucial data is produced and stored.

The Mcleamy curve

McLeamy asserts that during the life of a project there are many decisions to be made, always more and more detailed with time. A modification to the project means questioning choices made during all the other stages, which leads to the adaptation of all the details as well. A project is a net of decisions depending on each other, like an intricate knitting. If a change is required then the knitting has to be unravelled and knitted all over again.

During the project design phase the activities are started of defining the project and its feasibility.  Only in this moment are decisions able to be made in complete freedom when considering the costs of construction and the future use of the building.

The graph below shows that the freedom of decision is high at the beginning and it declines as time passes during the following phases of the project.  As it progresses, the possibility of making changes and influencing the future costs are gradually lost.



Curve of ability to influence the costs during a project life cycle. McLeamy.


The more the work advances then the more intricate the knitting becomes. If the project is modified at the beginning then the cost will be lower because fewer resources were spent and every team member spent less working time on the project. If the first graph showed that there is less influence on the costs with time, this second graph shows that the cost of modifications rises with time.

Curve of the cost of a modification of the project. McLeamy.


Therefore, if we want to have the control over the costs of construction, maintenance and demolition, any change must be adopted with as little delay as possible. The concept might sound elementary, but what happens in reality is that only during the last part of the project design phase the people who work in all the disciplines are involved (estimation of cost and time, structural engineers etc.). If this could take place at the beginning, the costs would reduce drastically.

Curve of the effort during a project life cycle. McLeamy


The graphs shows that the pick up in effort comes toward the third phase, when the project moves from a vague draft to a more detailed plan, and it is very difficult to transform the design of it into practice while optimizing the costs.

Historically, this situation comes from when the project design initially took the form of 2D drawings, which demanded a long time to be prepared and an even bigger effort to be fully understandable by people who did not participate to their development.  In addition, it was difficult to transmit other information regarding space and geometries when passing the data between the various experts. For all these reasons, the ideal optimization of the projects was nearly impossible, at least within an acceptable amount of time. Therefore, the project would proceed in a linear way without proper debates and discussions about the different aspects of the projects between the different professionals.

Curve of McLeamy. Anticipation of efforts during the project life cycle end involvement of all professional roles.


There is a much more efficient way to share data today.   The BIM enables the production, modification and sharing information in an extremely reduced amount of time.

All the professionals can be involved from the preliminary phases and can contribute to the optimization of time and costs thanks to their expertise.


Additional reflections

Costs distribution during the phases of the life cycle of a building


This graph shows the percentages of cost during the different phases of a construction project. It is clear that the majority of costs are sustained during the ‘use’ phase (energy, cleaning, daily maintenance, etc.). A client would be certainty interested in paying more initially for projects that reduce these costs to the minimum during the building life cycle.

From a project manager point of view, working with the BIM enables services to be offered that are always more requested and better paid. One day in the near future the BIM will be the only acceptable way to work and it is necessary to start the adoption of it as quickly as possible in order to permit a smooth transition of the whole system.

To summarize, BIModeling is:

  • A method to produce and store highly valuable data that can easily be stored and found at the right time
  • Optimization of the project choices and the consequential reduction of costs during the whole building life cycle.