Nicola Accialini
4 min readApr 1, 2022

Digital Twins, Model-Based Definition and more Digital Twins has now become a buzzword in manufacturing companies. However, when I interface with professionals, consultants and experts in the field, I discover that different meanings are attributed to this term. The main reason is that many companies that are offering services related to this sector are exploiting the digital trend, as they say “they strike while the iron is hot” for marketing purposes. There is nothing wrong with all of this, but we still need to do some semantic clarity. In this post we will describe some basic concepts that will help us once and for all to extricate ourselves in understanding what a Digital Twin actually is.

Digital Mockup

Mostly, when we talk about Digital Twins, we often mean a Digital Mockup, that is a 3D modeling of our reference object, a mechanical component or a production system. Digital mockups were born with 3D CAD and compared to 2D solutions they offer countless advantages for those who design the product, for those who design the production cycle, for those who have to buy goods and for those who have to sell a product. In particular, a 3D replica of a production system, for example, can be visualized using virtual reality systems to make a semi-real “experience” of the factory that has been designed, consequently going to clean up the details and reduce the risks associated with the investment of often considerable capital. Finally, it is becoming increasingly common to use such virtual and / or augmented reality devices for marketing purposes.

Model-based Definition

The Model-based Definition (MBD) is a methodology that basically consists in attributing all the dimensional and geometric specifications (but not only) directly to the 3D model. As a result, the table setting becomes obsolete, but this is not the main benefit. In this article 5 reasons why it is worth using this approach are listed, which are summarized below:

  • further automate production: for the programming of numerical control machines, many information normally present only on the table must be entered manually by a programmer. With an MBD, this information can be automatically read from the 3D model
  • increase the efficiency of the exchange of technical information: for particularly complex products, the items on the table sometimes become difficult to interpret improve product quality: for example, tolerance management can be optimized
  • represent a competitive advantage in manufacturing: there are countless advantages in its use, from the aforementioned numerical control programming to final testing through point acquisition systems
  • provide complementary support to 4.0 technologies: data can be exchanged automatically through IoT systems, analyzed using machine learning techniques, consequently increasing the level of autonomy and flexibility of processes

Digital Thread

For Digital Thread we mean the implementation of a digital information management system for the entire life cycle of a product. The MBD is the fundamental element for a digital approach during the design and production phase. However, with the Digital Thread, the benefits generated by a continuous exchange of data are also extended to the subsequent phases, namely:

  • during operation: the system is able to exchange and process data in real time
  • in the product support phase: the data exchanged allow a more efficient and timely support, and to react more quickly in case of malfunctions or system failures
  • in the decommissioning phase: from a circular economy perspective, it becomes essential to have information regarding the disposal and reuse of components

Below is a schematic representation of a Digital Thread approach according to General Electric:

GE Digital Thread

Digital Twin

And now let’s answer the question posed at the beginning: what is a Digital Twin?

Digital Twins consists of a virtual representation of an object or a system capable of behaving, in real time, in the same way as the physical system thanks to a continuous data exchange.

Consequently, Digital Twins may use a digital mockup (although this is not always the case), but above all an infrastructure equipped with cyber-physical systems capable of exchanging information regarding the kinematics and / or dynamics of the physical system, depending on the level of complexity to be achieved. What are the advantages of implementing a Digital Twin? Here are a few:

  • Remote monitoring of the production system
  • Upstream analysis of scenarios
  • Decisions made on the basis of real data
  • Greater transparency
  • More flexibility

It is easy to understand how the implementation of a Digital Twin is not trivial at all and it is therefore necessary to evaluate the actual benefit and the level of complexity required on a case by case basis. In some cases, a digital twin can only be implemented to monitor a specific aspect of a factory, such as logistics. In this case, a digital mockup is not required in principle, but simply a 2D schematic representation of the factory to identify the flow of parts in real time.

Where to start?

In this short post we have highlighted the differences between Digital Mockup, Model-based Definition and Digital Thread to finally define more clearly what Digital Twins are. Therefore, depending on the specific needs of a company, it will be necessary to implement one solution rather than the other. If you want to learn more, check out our full catalogue!

Nicola Accialini

Engineer, consultant, digital entrepreneur and traveller, not necessarily in this order | Agile and Additive Addicted |