Dear TeamCAD website visitors,

We continue to cover interesting topics related to the BIM workflow and Digital Twins. As I announced in my previous article, "What Are The Digital Twins", in this article, I am going to cover an exciting topic about digital twins in the construction industry.

For the beginning of the text, one interesting question - do you know when and how digital twinning technology was developed? I think the answer will amuse you - the technology of creating a digital twin model, in the format we know today, which is an existing or designed object and an identical copy of the object in digital format, was created in 2002 and was first used in astronomy by NASA for the production or procurement of various components and systems from different suppliers.

Digital twin models have been used primarily to calculate the life cycle of components, systems, and various assemblies and structures after installation, production, and construction. Primarily, digital twins were used to estimate the cost of maintaining different components, systems, circuits, and buildings by making various simulations of phenomena and processes that would occur on existing objects using their digital format replicas. I assume that you have concluded that by accessing a digital replica of an existing building, component or system and simulating the various real-world impacts on them we come to the information on all aspects and causes of the life cycle costs of a particular object, component, or systems in a real environment and in the real-world impacts of different phenomena that interact with an building, component, or system in a much cheaper way.

After having fun with the interesting facts in the introductory part of the article and also learning the meaning of digital twin models, I want to focus on the very topic of this article, which is the purpose of digital twin models in the construction industry.

For a start, we must bear in mind that we have more participants in the building construction, namely the designer, contractor, and investor. Depending on the role in the project process, I am sure that you have in mind that their interests may not be identical when it comes to designing a digital twin.

The interests of the designer and contractor in designing the digital twin in the design process are mainly related to the optimization of their own work. They have no primary interest in passing on the digital twin model of the constructed building to the investor after completing the project and building construction, i.e., something like that represents an additional cost to them.

On the other hand, the investor should be very interested in getting a digital twin model of the finished building for reasons that I will list below.

Digitalni blizanci ilustracija

Unfortunately, it often happens that the investor does not require the making of a digital twin model of the constructed building at the end of the design process. Most often, he does not realize its value and the potential savings in operating costs and life cycle costs of the built facility, which it will bring to the investor, the owner of the facility, the user of the building or facility manager. Also, a common cause for the absence of a digital twin model of a built facility is a certain skepticism with the investor, owner, or user of the facility or facility manager.

Inženjer na gradilištu

The most common questions I hear in discussions about the need to build digital twin models in the construction industry are:

  • Why do I need a digital twin model of a building, if I have a construction stage project?
  • Why do I need a digital twin model of a building, if I have an as built project?
  • What additional value does the digital twin model give me?
  • How to manage the project process so that the investor will eventually get a cheap but quality digital twin model?
  • Does it make sense to create a digital twin model if the building is already built?
  • What to do with a digital model of a digital twin after making and purchasing it?

Šta uraditi sa modelom digitalnog blizanca?

Before giving detailed answers to each of the questions asked by the investor, the owner, the user, or the facility manager, the basic question is asked - who should fund the creation of the digital twin model of the facility? It is not grateful to go into this dilemma from this position and to advise who should finance the digital twin model, as this may depend on the contractual obligations between the investor, the owner, the user, and the facility manager.

However, I am going to be free to suggest to the investor that, in the case of the construction of a brand new building, if it has a capable BIM manager who manages the BIM project process from the start of the project to the completion of the construction, it can have significant financial benefits if he gets the digital twin model at the end of the project. He can accomplish this by "refining" the BIM model of the construction stage project, which he could then hand over or sell to the owner, user, or facility manager. On the other hand, when it comes to creating a digital twin model of an existing building, it seems most logical to me that the costs of making the digital twin model should be taken over by the person who manages the life cycle and pays for the maintenance costs of the building and its equipment, which is usually the owner or user of a facility.

To simplify the terminology and relations between the investor, the owner of the building, the user of the building and the facility manager, below, I will look at the issue of the need to design a digital twin of the building through the prism of the user of the facility, since the user is the one who will pay the costs of operating the facility, it’s life cycle costs and the equipment in it, and the one should be most interested in the design and procurement of a digital twin model of the facility.

Troškovi operativnog korišćenja objekta i životnog ciklusa

Why Do I Need A Digital Twin Model Of A Building, If I Have A Construction Stage Project?

By definition, the construction stage project is a detailed design of the main design with all the necessary details defined for the project to be constructed. The problem with the construction stage project is that, in practice, the built facility is almost always significantly different from the solution given in the construction stage project for various justified or unjustified reasons, which the designer and contractor did not consider when designing the construction stage project.

Therefore, we can conclude that a construction stage project cannot give an entirely exact digital or paper 2D replica of the completed state of a newly constructed building.

When considering building structures that were built before the advent of digital twin model technology, this puts the facility user in a worse position, since from the 2D drawings on the paper sheets he is not able to grasp every detail of the building that he uses or in an orderly fashion track the changes, maintenance and life cycle costs of each element in the building. Also, it is almost impossible to imagine that the contractor was so conscientious during construction that everything, even the slightest deviation from the construction stage project, was documented by an additional graphic revision.

Why Do I Need A Digital Twin Model Of A Building, If I Have An As Built Project?

To better address this issue, it is best to look at the very definition of an as built project.
"The as built project is being made to obtain the use permit, use, and maintenance of the facility.
The as built project of a completed facility is a set of mutually synced projects showing all the details of the constructed facility necessary to determine its suitability for use.

The as built project can be made for parts of the building which, in the opinion of the technical inspection committee, or following the technical documentation, represent the technical and technological unit and can be used as such independently, and for which the suitability for use is determined in accordance with the rulebook governing the technical inspection of facilities and for which a special use permit is issued. " (definition is taken from the site from the Rulebook On The Content, Manner, and Procedure Of Preparation And Method Of Control Of Technical Documentation According To The Class And Purpose Of The Facility - Official Gazette RS number73/2019. 

From the very definition, we can see that the as built project, whether in digital or paper format, somewhat considers the facility maintenance, but does not provide clear guidance on how to document the maintenance of the facility, how to assess the monthly, quarterly, annual life cycle costs of the facility and installed equipment. From a law point of view, it's enough to do an as built project that would document all deviations of the building from the construction stage project, which completely ignores the process of the complete life cycle of the building and the installed equipment.

What may be good about the overall story of an as built project is that in newly designed and constructed buildings and equipment, if the BIM workflow is implemented appropriately in all project stages, the BIM as built model can be taken as a starting model for development of a digital twin model of the building and the installed equipment. In simpler terms, adding attributes relevant to monitoring the operating life cycle cost of a facility to the BIM as built model is the most financially viable way to obtain a digital twin model of the construction facility and the equipment built into it. What precisely this means, I will explain in answer to the next question.

Najpovoljniji način za izradu modela digitalnog blizanca

What Additional Value Does The Digital Twin Model Give Me?

If we are talking about a BIM project, the simplest explanation for the difference between a BIM as built model and a digital twin model is that the BIM as built model provides static information about a built object, such as its geometry, equipment capacity, properties of used materials and equipment, etc. In contrast, the digital twin model contains dynamic data such as maintenance costs and the life cycle of all elements of a building and equipment installed, as well as elements that simulate various “real-world” impacts on them. The digital twin of a building and its built-in equipment enables the cost anticipation of each element during its life cycle. These costs can be predicted on a monthly, quarterly, yearly, or multi-year basis, which can provide valuable information to the investor or user of the facility to optimize and more effectively manage its own finance.

Zgrada digitalni blizanac

How To Manage The Project Process So That The Investor Will Eventually Get A Cheap But Quality Digital Twin Model?

Assuming we are talking about a BIM project, the most straightforward answer to the asked question is that the investor, during the preparation of all project phases, has in his team an experienced BIM manager (employed by the investor or hired as a BIM consultant), who will manage the BIM requirements in the interest of the investor during all stages of the BIM workflow. The starting document, which should also form part of the contract between the designer and the contractor with the investor, is called the "BIM Execution Plan", a BIM project execution plan, which manages the delivery of the BIM project at different stages of the project. This document, usually drafted by an investor, defines what BIM models need to contain at different stages of the BIM project process, protocols for names of varying BIM elements in discipline models to optimize and automate the BIM project process (naming convention), collision definitions for each of the stages of the BIM project process, the platform on which the BIM combined model will operate, the "level of detail" (LOD) of the discipline elements throughout all stages of the BIM project process and many other things.

I think it should be reiterated here that the process itself between the BIM as built model and the facility digital twin model should be an integral part of the BIM Execution Plan, since it is more than evident that something is in the investor's interest.

BIM Execution Plan

I am going to write about the BIM Execution Plan in detail in one of the following articles. The previous brief description of what the BIM Execution Plan should contain, I just wanted to give an idea of why the investor needed it. It seems logical that the ultimate goal of the investor should be to create a digital twin to use after the construction. An experienced BIM manager or BIM consultant can assist him greatly by developing a BIM Execution Plan and managing the complete BIM workflow.

Does It Make Sense To Create A Digital Twin Model If The Building Is Already Built?

I think there is much need for a digital twin model for an already built facility, and there are many reasons for this. The first and foremost reason is that as time goes on, every building and installation requires more money for maintenance, more frequent failures in mechanical, electrical, and plumbing installations. Also, every change in the building regulations involves specific works, and there are more of them as the building structure or equipment in it is older. With this in mind, it is almost impossible to see all the changes that have taken place over the years of using the building, and every user of the building is aware that there will be many more changes, alterations, replacements, and upgrades in the future.

The logical conclusion is that in order to consider the cost of maintaining a building, it is almost necessary to create a digital twin model of an existing building. Practically, there are no substantial differences in explaining why a digital twin model of an existing building is needed compared to the building being designed. In both cases, the essence of the digital twin model is to enable the facility user to view the life cycle costs of the facility and the installed equipment.

The only difference is that as time goes on, the cost of maintaining older buildings is increasing, so the digital twin model is very precious in assessing the cost-effectiveness of further investment in existing facilities and equipment built into it.

Da li ima smisla izgraditi model digitalnog blizanca?

What To Do With A Digital Model Of A Digital Twin After Making And Purchasing It?

The answer to the last question I am going to discuss in this article should be, at the same time, a recapitulation of everything we have learned about the need for digital twinning in the construction industry.

First and foremost, the purpose of developing a digital twin model in the construction industry is to obtain, in a digital format, and in a much cheaper way, a user of a facility about all aspects of the life cycle cost of a particular building, component or system in a real environment and the real effects of different phenomena that interact with a building, component, or system.

When a facility user purchases a digital twin model of a facility and built-in equipment, it would be best to do monthly, quarterly, annual, and multi-year cross-sections of building and equipment maintenance costs so that tenant can manage finances in the best possible way.

Any changes to the building itself or the equipment built into it must be updated in the digital twin model as well since future changes cannot be properly tracked nor can the costs of future maintenance work be monitored unless the digital twin model is a perfect digital copy of the building current state and the equipment built into it.

Upravljanje modelom digitalnog blizanca

And at the very end of the article, I will make a personal comment and my more free-standing view of the digital twin model in the construction industry. The digital twin model of a building and equipment built into it is essentially a BIM as built model, with added functionality that can be used for tracking the life cycle cost of the building and the equipment built into it. In order to maintain the status of a digital twin model of a facility, it is necessary that it is continuously updated and that all changes from the real - physical world - are transferred to the digital world, i.e., into the digital twin model of the existing building and the equipment built into it.

I would also like to conclude this article on digital twins in the construction industry and my view of how they can help the construction industry through cost optimization and better functionality, both for under construction facilities and already built facilities.

Finally, I would like to take this opportunity to announce my next article, "Data Management In The Digital Twin", in which, through the examples, I will try to show you the need to think for yourself about the need to design a digital twin of your building.

If you have any questions, comments, or want to know more about the topic I covered in "Digital Twins In The Construction Industry", please contact TeamCAD, who will be happy to provide you with 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 next time,
Predrag Jovanović 



Previous article on the same topic:

"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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