Header widget area left
Header widget area right

The BIM components and the workflow for a correct engineering

Michele Cavallaccio
News, Revit, Workflow

Why we do not find on the web reliable and quality BIM objects?

When it comes to BIM components, the first question that arises is how to be able to find in the great confusion of the web the right platforms to download and share reliable and quality elements.

For those of us who deal with this type of problem on a daily basis, you will know that most of the time you come across elements (called “families” in Revit’s consolidated language) that present a level of detail and information that is often complex and incompatible with the models themselves.

Objects, true three-dimensional representations of real products, contain parameters and levels of detail that simultaneously include metric, engineering, performance and maintenance information. But as often happens, when these are carried out by third parties and not directly by the manufacturing companies (since they do not have sufficient expertise in BIM), the risk is to share products that are too complex or nested, difficult to manage or to import with inside of our models.

The workflow for a correct engineering of the MEP components

When one speaks then of the MEP category and therefore of MEP families, the subject becomes even more delicate. The workflow for the realization of a MEP family is not obvious and it is therefore good to follow certain basic rules or guidelines to make this work easier. If you want an indication of who does this activity every day, often several times a day, the best steps to follow are the following:

  • First of all, have all the technical documentation necessary for the creation of a family (technical data sheets, DWG format file with dimensional description of the object, operating system diagrams);
  • Then identify the category to which the product belongs, in order to select the most suitable template for the creation of the family;
  • At the time of modeling, take into account the fidelity of the reproduced object compared to the real one, respecting the minimum dimensions in terms of memory (avoiding to create too complex and detailed geometries and minimize the nidifications. Take into account the so-called “clearance zone”, ie the minimum distance for maintenance and inspection of the product once in place).
  • Once the geometry has been created, create the MEP connectors that is the key elements to transform a simple geometry into an object with a design value. In order to ascertain with certainty that the system that is modeling engineering functions, it will be necessary to correctly evaluate this type of element, through several steps:
  1. The flow configuration, which allows to manage the interaction of flow data between families connected in the same system (if set to “pre-set”, the flow data will be input from the connector as input into the system, otherwise, setting “calculated”, the design data will be received by the system).
  2.  The flow direction allows selecting the direction, based on the system associated to the connection and the type of MEP element.
  3. System classification allows selecting the classification based on the type of system to be associated with the connector.
  4. The association of the data corresponding to the flow and pressure drop to the related parameter, which will be of “type” or “instance”, depending on the type of MEP element that is being used.

Once the appropriate parameters have been defined for all the MEP         connectors of a family, it will be possible to transfer the basic engineering information to the system and finally start the MEP design.

  • The last step of the workflow is to verify the correct functioning of the family, by inserting it directly into the system it belongs to.

A practical example for the correct valorization of Mechanical Systems

To give a practical example, if we refer to an air delivery system, deepening the functioning of a “Diffuser” family and an “AHU” family, the parameter development procedure should be as follows:

– The diffuser used for the air delivery system will have the classification of the “supply air” system as the “internal” flow direction and the flow configuration will be set to “pre-set”, in order to enter the data of carried from the connector as input into the system.

– The AHU, which will be upstream of the system, will have the “external” flow direction and the “calculated” “flow configuration” in order to receive the sum of the project data entered by the terminals in the system. The “system classification” will instead always be “supply air”.


To conclude on the topic of BIM components and families, we can say that it is fundamental to evaluate their origin and provenance before inserting them into our models. The importance of proper engineering is not only linked to the quality of our work, but also to our projects. Always keep in mind the correct workflow for the enhancement of our BIM objects is an indispensable practice that can not be ignored.

This is why the manufacturing companies, suppliers and companies should also revolutionize their way of working, aligning themselves with the new methodology and adopting the processes. Only in this way can the production of elements not correctly exploited be avoided, allowing consultants and designers to always have adequately sized and parameterized components at their disposal.

Comments are closed.