What Are The Digital Twins?

Dear TeamCAD website visitors,

We continue to cover interesting topics related to the BIM workflow. As I announced in the previous article, „Small But Big Savings in The BIM Workflow – Examples“, in this article, I am going to cover a very interesting topic about digital twins.

Let’s start by defining what the digital twins are. There are many different interpretations of what a digital twin is, depending on the point of view. If you read my first text “Advanced BIM Data Management”, where I hope, I managed to describe you different views of the BIM model, depending on the perspective from which the BIM model is viewed. The situation with digital twins is very similar, where seeing a digital twin depends heavily on whether it is viewed from a designer, contractor, or investor point of view. To make things more interesting, with digital twins we often have a case where “designer, contractor and investor” are combined into one view of the digital twin model, for example working with manufacturers in the automotive and aviation industries, then in shipbuilding, in the production of mechanical systems, process lines, etc.

cargo ship CFD simulation

The most common definition of a digital twin is that it is “a digital replica of physical data, processes, systems and digital simulation of reality, which can be used for various purposes.”

After defining the term digital twin, many BIM specialists will recognize that the BIM model can easily be placed in the context of the digital twin, which is not so far from the truth. In chronological terms, the BIM model can be seen as the very beginning of digital twin generation, i.e., as his starting point. If you go back to the definition of a digital twin, the BIM model can be conditionally viewed as a digital replica of real data. 

BIM simulation

However, the BIM model cannot adequately meet the requirements of the digital twin model, which can be a simulation of the life cycle of a building, different types of industrial process simulation, simulation of building behavior during a fire, evacuation of people during a fire, simulation of crash tests in the automotive industry, particle motion and their behavior during movement, etc.

It is important to note a few other things related to the digital twin. The digital twin represents one of the pillars of the fourth industrial revolution, and the potential and savings of such an approach are increasingly evident.

Digital twins can be classified in many ways depending on the person’s point of view.

I think the best way to classify digital twins is to digital twin objects that are under fabrication or construction and to objects that are already made or built. Still, we need additional information about those objects. What we will not be able to avoid in this article as topics closely related to digital twins are the digital tools of simulation, the involvement of machine learning, and artificial intelligence.

Digital twins of objects being fabricated or constructed

With this type of digital twin, we typically mean objects that are subject to future fabrication or construction. In this digital twin generation workflow, we first mean creating a BIM model, which is almost always an object or part of it being design. By object or part of a designed object, I mean objects such as buildings or parts thereof, cars or parts thereof, production line or parts of a production line, dynamic objects, simulation of the destruction of a building (progressive collapse), etc. All of the above objects or parts of objects that are subject to future fabrication or construction, if you have noticed, are characterized by the fact that from a BIM point of view they can be considered as fully static BIM models and cannot be attributed to the dynamic properties that underlie any simulation process. 

VR virtual reality

This further leads us to the conclusion that the critical difference between the BIM model and the object’s digital twin, which is the object of fabrication or construction, is the ability to simulate with different digital tools the influences from the real environment, that is, to apply different dynamic influences to the BIM model. Practically, digital tools that enable different simulations modify the BIM model into a digital twin model.

Digital Twins of Objects That Are Made or Built

With this type of digital twin, we typically mean objects that are already made or built. At the very beginning, I face the question of the skeptic in himself, who asks me the question: “And why would you create a digital model or digital twin for anything that is already made or built? Apart from the additional cost, which cannot be considered as any benefit, what economic benefit can one expect from such a model? “

The digital realist in me has a ready answer, which will hopefully easily disarm the skeptic in me through a straightforward example from everyday life.

I belong to a generation that used rotary dial phones daily in childhood.

Later, of course, I used cordless home phones, and here I am in the modern era in which I happily use all the benefits of human achievement, and therefore “smartphones”.

Let’s compare what information the rotary dial phone contained about its owner versus the smartphone. Apart from the phone number, to which you could call not me but my family, there was virtually no information regarding the phone owner. With the advent of smartphones, a wealth of information about the phone owner and the number assigned to the owner is available. Free international communication is possible via the telephone number and specific applications. The information about himself that the smartphone user wants to share is accessible to everyone.

It’s important to note that the first iPhone came out in mid-2007. From a smartphone user perspective of just twelve years, we can’t imagine going back to the old handsets with the rotary dial, since the capabilities between it and the smartphone are merely hard to compare – both devices are phones, but they do not necessarily belong to the same device category.

In a very similar way, we can look at an already made or built object that has its own digital twin and an object that does not have its own digital twin. Namely, even though the object already exists, we really know little about it since the made or constructed object contains very little data in itself.

The skeptic in me wonders if it is necessary that now, even though we have new and very effective digital tools to digitize existing objects, we need the facilities we have already built to be digitized? Quite simply, why do we need it, and what will the digital twin of the made and built object serve us in the first place?

Take the existing building as an example and imagine the situation when walking through a building to ask the building owner or facility manager what are the properties of a wall – what is its thickness, what material is it made of, what is the brand of the concrete wall, is it bearing wall, whether it has a finish and of which thickness, from which material the finish is made, is the load-bearing capacity of the wall such that we can hang brackets for pipes of a certain weight, which is the fire resistance of the wall, whether we can make a hole in the wall to accommodate the damper and “pull-in” the cooling or heating duct when planning a wall painting, what is the wall area in order to calculate the cost of wall painting, etc.

I am convinced that it would take a few days for the building owner or facility manager to answer the above questions if we assume that he did not have a digital twin model of the building. Simply, the owner of the building or the facility manager would have to go through a pile of paper to get the information I needed, he would have to contact the archive for some information, and I am sure he would not be able to find some information.


However, if the building owner or the facility manager had a digital twin building model, I am confident that for some questions, I would get answers within minutes, and for slightly more complex questions, such as wall openings and wall-mounted pipe holders I believe I would get the answer in a few hours.

Revit parameters

I think that you have, through a straightforward example of an ordinary wall, seen the potential of a digital twin of an existing facility, which, for example, can save you significant financial resources by optimizing the cost of maintaining the facility, finding the best option for renovating, upgrading and adapting industrial facilities to a different purpose and finally when calculating the operating costs and life cycle of the facility. Try to imagine how much savings you can make when maintaining mechanical and electrical installations, production lines in factories, maintaining fire installations, etc.

I am going to write much more about digital twins of objects that have already been made or built in the following article: “Digital Twins in The Construction Industry,” since my wish for this article is to stay focused on the concept of the digital twin in the broad sense.

So let’s move on to a topic that combines the need for making a digital twin in both objects that are subject to fabrication or construction and in objects that are made or built.


Digital Simulation Tools for Digital Twins

When talking about digital simulation tools for the digital twin, keep in mind that we are entering the rainforest, and it is very difficult to capture all the tools available. Therefore, I am going to list just a few of the most important digital simulation tools for digital twins and write a few sentences about each tool.

  • CFD (Computational fluid dynamics) is a calculation of fluid dynamics and is part of fluid mechanics, which uses numerical analysis and structured data to solve problems related to fluid and gaseous fluid behavior. CFD analysis has an extensive application including forces and moments on various digital models, pressure in tubes caused by liquid and gaseous substances contained in the tubes, explosion analysis, simulation of motion and flow of different types of particles, temperature action, simulation of weather, the behavior of digital models in an air tunnel, etc.

CFD car simulation

  • Dynamo and Python are digital tools that are detailed in the article “BIM Workflow Automation”. Here, I would like to avoid a more detailed description of Dynamo and Python as digital tools that, in addition to automating the BIM workflow, are also widely used in data processing for digital twin models. If you would like more information about Dynamo and Python, please select this link.    
  • Sensors – For made or built objects, different types of sensors are used to measure the values needed to optimize pre-existing elements within an existing object. For example, sensors can measure the number of people in a particular room. Then the data obtained can be compared with the data assumed by the architect during project design. If the number of people in a given room is consistently higher than the projected number, the building owner can optimize the machine’s system of fresh air injection. Similar is possible with measuring the brightness of rooms. By comparing the data thus obtained, if an error is detected, the building owner can correct the deficiencies to give the building user adequate comfort.

  • Machine learning is a digital tool that is defined as a sub-area of artificial intelligence. Machine learning is a process where a machine is learning things based on the experience and imitation of human actions in certain repetitive circumstances. In simple terms, machine learning is based on observing the actions a person performs when encountering a specific typical problem. After several repetitions, the program that “monitors the human” learns and adopts the algorithm of human behavior and assumes the execution of the same operation that he learned “monitoring the human”.

Given that artificial intelligence is not yet able to make very complex decisions and look at the problems that occur with data generated by different simulations. I think that we cannot yet speak of the massive and default use of artificial intelligence as a digital tool to simulate the process in a digital twin.

The Savings That Digital Twins Bring

  • By applying BIM workflow and digital tools used in various simulations on the digital twin model, and with proper BIM management of the complete BIM project process, there are between 5% and 15% more problems in the early stages of the project process, that is, long before the contracting project and the construction of the facility itself, which brings significant savings to the investor financially;
  • The use of different sensors in buildings, which generate data through data processing platforms, helps to automate the equipment in the facility more easily and efficiently, which improves the energy efficiency of the building and at the same time improves the comfort of the building occupants;
  • By analyzing the data collected through sensors in already fabricated and constructed objects and incorporating such data in the design process of future objects, the investor makes significant savings in the speed of fabrication or construction of the object, in the selection and installation of equipment, which, as a consequence, brings significant financial savings to the investor;
  • By developing and permanently implementing a digital strategy, which involves developing digital twin models, incorporating different sensors into existing objects and processing the data obtained from them, the investor receives “collective knowledge and experience” classified by object type, which in future projects of objects classified by type and purpose, brings significant financial savings at all stages of the project, then during the construction of the facility and in the life cycle of the facility itself;
  • Given that it is difficult to expect a price drop of urban construction land and site fitting, the only segment where an investor of building construction can make savings is to optimize the implementation of the BIM workflow and to produce digital twins, in which the digital performance of the simulation tools will permanently improve the performance of the building in all stages of project design, during and after construction.

This would end the article on digital twins and my view of how they can help in many areas through cost optimization and better functionality, both for objects that are not fabricated or built, and for objects that are fabricated or built. I would also like to take this opportunity to announce to you my next article “Digital Twins in The Construction Industry”, in which I hope to bring you even closer to the concept of digital twins and to indicate the need for you to think about the need to design a digital twin of your object.

If you have any questions, comments, or want to know more details about the topic I covered in “What Are The Digital Twins”, please contact TeamCAD, who will be happy to provide additional information.

Also, if you need any help in designing the process of how to get a digital twin model, or you need to create a digital twin model yourself, TeamCAD will be happy to support you.

Until the next article,
Predrag Jovanović

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