3 Keys to distinguish the Quality of a BIM Model

3 Keys to distinguish the Quality of a BIM Model

The benefits of implementing BIM methodology are potentially immense. Especially when what is known within the industry as "Maturity Level 2" is reached, i.e. when the realization of three-dimensional models goes beyond purely visual purposes. They incorporate the "information" dimension and are made to achieve objectives such as: having coordinated assets, increasing production efficiency, increasing the quality of the finished product and caring for the environment by working in a collaborative environment.

This methodology allows to manage high volumes of information associated to digital twins of real physical components, something that before, using other processes, was not possible.

However, the increase of information by itself does not ensure better results, nor does it meet the objectives mentioned above. It is key to understand that information must be managed professionally, with processes, manuals and protocols. If the accuracy and integrity of the data is not known, it may be counterproductive and lead to more problems than solutions. In that scenario, errors would increase rather than decrease.

Therefore, as important as the implementation of the methodology is quality assurance. The information integrated in the virtual components must be validated and be sufficient to meet the objectives for which the models are created. For the methodology, it is just as negative to work with models with little information and precision as with those with excessive and overloaded definitions.

Considering the two extremes, the first scenario produces models that fail to meet the uses for which they were designed, while the second can hinder manipulation and management. The weight of the files is critical for proper functioning, especially when models are hosted in the cloud, both for collaborative work and for management.

How can we guarantee the quality of the models and their components?

At Axet, we have a team of quality control specialists who are responsible for ensuring the integrity of the content we generate. The main objective of this team of professionals is to ensure that the models go through the different stages of the project in a healthy way. They verify that the components incorporate the necessary information to respond to the different phases and uses for which they were designed.

Natalia Olivera, partner and COO of Axet, is in charge of designing the processes and tools that will be executed by the quality area. Below is an excerpt of the review process map for a model that will be used for 3D coordination in the design and construction stages.

BIM uses template and its codification according to stage (non-standardized use codes, exclusive for Axet).

Process diagram designed for internal use in Axet.


Some of the tools used by the team to optimize these review and communication processes are: Solibri, BIM Collab, BIM Track, Navisworks, Design Review and the production software itself, such as Revit and Archicad. Below we highlight three key issues that are key to ensuring quality during project development.


1.Verify standards and requirements

This article talks about properties within a BIM model, it is not the intention to focus on the processes that produce that model. Processes and protocols are assets of the organization, essential to achieve optimum performance and high quality levels, but they will not be discussed here. It is understood then that they are already incorporated in the organization when the initial BIM implementation was carried out.

At the beginning of the project, a BIM Execution Plan (BEP) must be defined in which general guidelines are established, not only for the link between the bidder and the client, but also for the interaction of the actors involved in the project and the information exchanges. These guidelines are the first step to ensure the quality of the methodology.

Definitions such as the responsible actors, the Common Data Environment, the logical structure, the file structure, the coordinates, the codes, the BIM uses and objectives, among others, are essential to achieve a successful project.

All the definitions established in the BEP should always be present when reviewing the validity of the models. A good practice is for those responsible for quality to have the BEP printed or easily accessible, since they should be consulting it permanently in order not to lose focus of the efforts to be made both in production and quality.

The second level is the definition of manuals and protocols. These establish a series of requirements and partial objectives, the fulfillment of which will make it possible to obtain projects that meet the objectives set. In general, these assets are developed internally by the bidding company in charge of the virtual construction. The company usually has a library of templates with these files, so as to use the ideal one for the objectives set, and these in turn are linked to a library of "checklists". These checklists are incorporated into the tools available to the quality team.

An example of protocol is known as "naming convention", which refers to the nomenclature of all the assets that make up the project: name of the federated model and its referenced models, of the components, of the templates and spreadsheets, etc.

Some other protocols we use in Axet are:

Strategy Scorecard
General modeling protocol
Manual for the use of the CDE
Protocol for the use of Design Review
DWF Dictionary
Protocol for creating families
Protocol for the creation of details
Working protocols and manuals are what make virtual construction a meaningful and cost-effective process. They link the client's expectations with the guidelines for the production team and with the definitions to be controlled and monitored by the quality team. They are the basis for a successful project.

We must also take into account three other very important aspects in terms of standards and requirements; on the one hand, the veracity of the model based on the references to be taken as a starting point. This can be based on hand drawings, construction graphics created on a CAD platform, schematics, or any other input. The fundamental thing here is to be precise with respect to the information received and that this is reflected in the resulting model.

As a second point something that is key in the handling of computer tools and may seem obvious, but it is not always so: to properly follow up and make the right decisions regarding the warning messages issued by the software we are using. In practice, those signs are "annoying" and the inexperienced user tends to close them without paying attention. BIM software is intelligent and those alerts often issue important warnings based on the parametric behavior of the assets. If these problems are not addressed in time, they can generate an effect that eventually prevents us from having healthy models. They may even force us to have to change elements that had already been closed. To avoid conflicts, it is important to manage these warning messages well.

Finally, the definition and management of the level of detail or LOD. At some point in the project planning, it is necessary to establish a LOD to work with. This LOD is adjusted based on the objectives of the model and must be respected. As already mentioned, it is not advisable to exceed the level of detail and information, nor is it advisable to have an absence of detail and information. Both situations are counterproductive, although an unsuspecting user may think that more information is always better. Adding more information can distort development times and needlessly make the model more complex. If some elements need more information, and a different treatment, such exceptional handling should be part of the overall approach strategy.


2. Verify the integrity of the model

When working with a BIM methodology, information is not only important, but abundant. Too much information can be equally or more counterproductive than too little. That is why it is important to think about how much and what information is relevant to the project objectives. There are certain data, some geometric and others logical, that will be added as the project life cycle progresses and are fundamental to make the model behave in an intelligent and parametric way, in order to avoid repetitive work, uncertainties and errors. For example, the linkages between walls, levels, slabs, floors, ceilings, roofs, ceilings are key. Not necessarily that they all link to each other, but that they do it in an intelligent way based on the functioning of the project. A clear case is that of the wall that is linked to the pavement containing the interior finish, so that when one of the objects is modified, the other accompanies that change. Something similar can happen with walls and project levels or ceilings (depending on what is more convenient for the specific project). It is a good practice to use rules for the construction of the models, that is, to generate programming within the assets so that certain actions automatically produce another action or a response.

There are reference elements, planes, levels, grids, local coordinates, geographic coordinates, that must be managed with a good criterion so that the model fulfills its objectives in an optimal way.

By analyzing the model in section, in real perspective or in isometric, it is possible to verify if the coordination between the components is well worked. The structure with the masonry for example, or the sanitary with the structure, in short, the coordination between different specialties or subcontracts.

3.Verify the ecosystem of the file

Spreadsheets or tables

Spreadsheets help to organize and analyze the logical information of the BIM model. In many cases, visualizing the properties of the elements of a given category through these spreadsheets, to which filters can even be applied for a better and clearer reading, is a practical and efficient way to detect missing or erroneous information. If a BIM model does not have enough spreadsheets created, it seems logical to think that its data may not be entirely faithful to the construction reality. The spreadsheets are even linked to the previous point, as it has to do with the integrity of the model.

Project navigator

Regardless of which BIM software is used to create the models, the project navigator (the window that organizes the various views) has to be intelligently organized. Views, sheets, plans, schedules and other components must not only have a consistent nomenclature, but also an intelligent structure. There will also be working views, which allow manipulation of the BIM model information without the risk of affecting the views shown on the presentation sheets, which meet certain standards to achieve the best visual result.

A chaotic project navigator is a clear sign that the methodology is not being applied and used intelligently or that the model is not mature enough.

Overall organization

Quality must be a commitment of all the actors, that is why it is critical that from the beginning the modelers are orderly and respect the constructive logic when creating components, take into account the structure of properties and the classification of information.

Modelers must work as the first barrier to prevent errors or detection of missing information.

One strategy to make this happen is to incorporate checklists not only to the quality team, but also to the production team. The modeler should then do an initial review of their work and complete the production checklist before releasing their work to the control queue.

Going specifically to the components that are used in the projects, equipment items or doors, windows, etc., it is important to keep in mind that it does not always add value to use an official manufacturer's model. It may happen that a company or brand has its products developed in BIM and ready to be downloaded by users, however, it is essential to validate the quality of those components before using them. Often construction manufacturers add a lot of geometric detail to their models, or many custom parameters that are not relevant, generating excess bytes of information.

If the component is repeated several times in the project, it can increase the file weight and complicate the manipulation and time. In other cases, editing the relevant parameters of a component, choosing them from an endless list, becomes tedious. This is why, due to the degree of maturity of the industry, for the moment in Axet we prefer to have our own library of components, with a defined level of detail and a list of relevant parameters that we manipulate easily. Anyway, we share for the future the vision of an OpenBIM ecosystem and national, regional or even global libraries.

Tools for quality control

Quality control is a dynamic process, which accompanies the different stages of project development. To achieve a control process that achieves a good rhythm, improvisation must also be reduced and "handcrafted" methods must be avoided. Three important points are listed below.


When we talk about automation we include several concepts that, mainly, point to the use of the tools that each software involved has to avoid manual review and minimize repetition, both in the work and in the subsequent control.

Also in this case, automation is more important in the process than in the result. However, in the model that remains as the final product, it is possible to find indications of the use of these tools.

Templates / View Definitions

Another important point within process automation, in order to reach a reasonable level of productivity, is the handling of view templates. For quality review and analysis, it is very efficient to use different filters or graphical overlays to quickly visualize different characteristics of the components. The advantage of creating a library of these templates for quality control is that time will be invested once and then they can be loaded into future projects. This generates a virtuous cycle of efficiency.

Interference detection

As the BIM model is loaded with information and components, it becomes impossible to check in a purely visual way that the different components of all disciplines are correctly coordinated and do not generate conflicts. Interference detection is a fundamental tool with which the software itself analyzes and detects collisions between the different components of the model and shows their location in order to evaluate the situation and decide how to correct them.

At Axet we use Navisworks, BIM Track and Solibri to work with interferences. In general, we do not use the modeling software itself, since this other way we generate a better traceability and communication with the clients.

The virtual coordination service is the one that has become more relevant in the first decades of the methodology. However, it is necessary to be cautious, but above all cautious in the use of technology for this. The detection software will detect all the contacts between the different disciplines, but this does NOT mean that they are all problems. It is the technician's job to manage this information properly, providing the client with the relevant information.

In the last projects we have been involved in, in the first interference analysis the software gave between 2500-3000 conflicts. After the evaluation of our technicians, the really important to transmit to the clients were less than 20-30 groups of problems. This is the added value that the BMO (BIM Manager Office) must provide.


How to convert 2000-3000 conflicts to 20-30 problem groups?

Constructive thinking.
The drawings from which mechanical, electrical, fire and sanitary installations are created are usually schematic, while architectural and structural drawings are more similar to reality. Therefore, knowing how to build from a schematic is key to avoid mentioning problems that in practice will not exist.

Groupings by type of solution.
Many conflicts can be solved by proposing the same solution, therefore, all conflicts that are solved with the same indication or detail can be grouped together.

At Axet we categorize problems according to priority (critical, high, medium or low). This grouping depends on the complexity of the solution that will be necessary to resolve the conflict. It is not the same to adapt the route of a supply installation as a drainage installation. The movement of an extraction pipeline installation does not generate the same impact on the project as the movement of structural components.



At Axet we work every day knowing that these quality references are essential for the construction industry to make the qualitative leap it needs. For this, it is key to take advantage of the opportunities that technology offers today, but not simply for the sake of trying something new. The challenge is to transcend technology, to use it intelligently to modify processes that go beyond it and benefit the entire discipline. The goal is to achieve greater productivity, greater efficiency, thus producing better buildings, better cities, and ultimately, a better quality of life for all.