Lili:
Welcome to the podcast of the CircleRedu-project. Today, we will discuss the twin transition in the manufacturing and construction sectors. More specifically, we will talk about reverse engineering, 3D modelling and the digital transition from the point of view of the green transition and circular economy.
My name is Lili Aunimo. I am a principal lecturer and the project manager of the CircleRedu-project at Haaga-Helia University of Applied Sciences. My background is in computer science, and more specifically in artificial Intelligence, in which I did my PhD thesis back in 2007. I am here in the studio with Yan Peng, lecturer and researcher at Metropolia University of Applied Sciences. It is great to have you here, Yan, welcome!

Yan:
Thank you.

Lili:
Yan, can you tell us about your background?

Yan:
Yes, sure. I’m Yan Peng, a lecturer and researcher at Metropolia University of Applied Sciences, where I work in the Sustainable Development for Real Estate team. I hold a Master of Engineering degree from Metropolia and have worked as an architect for around 16 years. My background combines architecture and engineering. I specialise in computational methods for the built environment, including computational design, building information modelling (BIM), and digital twins. I am currently exploring how artificial intelligence can be integrated into teaching, research, and construction-related technologies.

Your project, CircleRedu, sounds interesting. Can you tell a bit more about it?

Background

Lili:
The CircleRedu project is about the green transition, circular economy and reverse engineering process in the manufacturing sector. It is a three-year project funded by the European Commission. The goal of the project is to create and pilot a course on circular economy and reverse engineering.

However, learning from other fields and benchmarking them is often very fruitful when innovative solutions and best practices are needed. This is why I am interviewing you as an expert in AI in the AEC industry.

Lili:
First of all, can you briefly tell what the AEC industry includes and what is out of scope?

Yan:
Thank you for the invitation. It’s a pleasure to be here. I’m looking forward to this conversation, especially because of your expertise in AI, which is becoming increasingly relevant to the AEC industry as well.

AEC stands for Architecture, Engineering, and Construction. It refers to the industries and professionals involved in planning, designing, constructing and demolishing the built environment. This includes from early design concepts to construction, renovation, and eventually demolition.

For example, in a building project, architects, structural engineers, HVAC engineers, interior architects, landscape architects, surveyors, contractors and project managers all work together throughout different phases of the project. As an architect myself, I’ve seen how multidisciplinary these projects can be. In one hotel project I worked on, more than ten different disciplines were involved already during the design phase.

Sometimes you may also hear the term AECO. The “O” stands for Operations, meaning the management and maintenance of buildings after construction is completed. In that sense, AECO covers the entire life cycle of built environment projects.

There are also several related industries that are connected to AEC but are usually considered separate sectors. For example, real estate focuses more on property business and ownership, software companies develop digital tools used by AEC professionals, and manufacturing industries produce construction materials and building components.

Since your project focuses on the manufacturing sector, I think there are interesting connections between our fields. Could you tell us more about the circular economy in manufacturing, and maybe share some examples?

Lili:
Sure. Circular economy is a business model where materials and/or products are reused, repaired, remanufactured, refurbished and recycled instead of thrown away and becoming waste. Circular economy aims at keeping materials and products in use as long as possible and thus it is very different from the traditional linear model where products are made from new materials, used and then thrown away. Typical examples of circular economy are the use of recycled materials in manufacturing or repairing damaged or worn-out products instead of throwing them away. Circular economy is enabled by current developments in various fields, such as technologies related to reverse engineering, additive manufacturing and AI enhanced 3D modelling.

Yan:
Ok, I see. Can you explain the difference between circular economy and the green transition in manufacturing?

Lili:
The green transition is a more generic term. It refers to the shift from environmentally harmful practices to more sustainable ones. Circular economy is one tool to achieve the green transition. Typical ways of achieving the green transition include actions such as reducing carbon emissions, using renewable energy, protecting nature and biodiversity and the efficient use of resources. Circular economy can contribute e.g. to the efficient use of resources through processes such as repair, refurbishment, remanufacturing and recycling. For instance, a manufacturer of printers may offer a printer-as-a-service business model to its customers. In this business model, when the printer is damaged, it is taken care by the manufacturer. The manufacturer may repair, refurbish, remanufacture or recycle it, but the customer is always provided with a working printer.

Can you now tell if there are specifics in the circular economy in the AEC sector? What is the most common way of implementing a circular economy? What are the current trends in AEC? How about the future?

Yan:

The transition to a circular economy in the AEC sector is gradually moving from theory into everyday practice. Instead of focusing only on recycling waste at the end of a building’s life, the industry is increasingly considering circularity from the very beginning through digital tracking, lifecycle assessment, and design for reuse and adaptability.

Lili:
I see. Can you tell what are the most common practices in circular economy in the ACE sector nowadays?

Yan:
Today, common circular economy practices include recycling construction materials and reusing building components.

For example, some demolition waste can be processed and used as raw material for new construction. Crushed concrete from demolished buildings can be used as recycled aggregate in roads and, in some cases, in new concrete products. Recycled plastics can also be used in insulation materials, pipes, and interior finishes.

Component reuse goes one step further. Instead of breaking materials down into raw materials, entire building elements can be recovered and installed in new projects. Examples include doors, steel structures, façade elements, lighting fixtures, and ventilation equipment that remain in good condition.

However, before discussing recycling or reuse, the most sustainable option is often to avoid demolition altogether. If an existing building can be renovated, refurbished or adapted to meet new functional needs, retaining the existing structure can significantly reduce both carbon emissions and energy consumption associated with demolition and new construction.

Circular economy principles should also be considered during the design phase of new buildings. Designing for durability, disassembly, maintenance and future reuse makes it easier to recover materials and components at the end of a building’s service life.

This is particularly important because buildings account for approximately 40% of energy consumption and around 36% of greenhouse gas emissions in the European Union. Improving circularity can therefore contribute significantly to broader sustainability goals, not only in the AEC sector but across society.

Looking ahead, several European regulations are expected to accelerate this transition. The Ecodesign for Sustainable Products Regulation, or ESPR, promotes more durable, repairable and recyclable products. The revised Construction Products Regulation introduces sustainability and digital information requirements for construction products. At the same time, Digital Product Passports provide structured digital records containing information about materials, environmental performance, and circularity.

As these data become more widely available, they can be linked with Building Information Modelling, or BIM. This integration will make it easier to assess the environmental impact, carbon footprint, and circularity performance of buildings throughout their entire lifecycle.

Lili:

What is the situation in Finland? Is there specific regulation related to the green transition that is a driver for change in the sector? And are there other drivers?

Yan:

Finland is often recognized as one of the global pioneers of the circular economy. In fact, it was the first country to publish a national circular economy roadmap in 2016. Today, Finland aims to become a carbon-neutral society by 2035, and the construction sector plays an important role in achieving that goal.

One of the most significant recent developments is Finland’s new Building Act, which entered into force on January 1, 2025. The legislation strengthens the role of low-carbon construction, lifecycle thinking, and digitalization throughout the building process.

For most new buildings, developers are required to prepare a standardized climate report based on Life Cycle Assessment, or LCA, as part of the permitting process. In addition, projects must provide information about the construction products used in the building. This information is updated when the project is completed, creating a more accurate record of what was actually built.

Another important aspect is digitalization. Finland is developing a nationwide Built Environment Information System called Ryhti, which supports the exchange of structured digital building information. Building Information Modelling, or BIM, plays a key role in this process by enabling machine-readable data to be shared throughout a building’s lifecycle.

Together, these developments support both sides of the twin transition: reducing carbon emissions and promoting a more circular use of resources in the built environment as well as fostering efficiency and innovations through digitalisation.

Lili
Thank you, that was very enlightening. Next, I would like to ask you about the role of reverse engineering as an enabler for circular economy in the construction sector. Is the reverse engineering process applied and if yes, how?

Yan
Reverse engineering… To be honest, the first time I heard the term was probably from the TV series Silicon Valley, where they talked about analysing software and rebuilding a legally distinct clone. It sounded a bit questionable from an ethical perspective.

However, I assume the reverse engineering we’re discussing here means something quite different. Could you explain what reverse engineering means in the context of circular economy and sustainable manufacturing?

Lili:
Sure. I am happy to explain what reverse engineering means in this context. Reverse engineering means a process of analysing a product to figure out how to make it. Reverse engineering is used when the original design documents do not exist or when they cannot be accessed for some reason. This said, I fully understand your concern about using reverse engineering in an unethical way. It is very good that this came up.

In circular economy, the ways of keeping materials and products in use as long as possible include reuse, repair, refurbishment, remanufacturing and recycling. The reverse engineering process is needed when damaged or worn-out products that have no documentation are repaired, refurbished and remanufactured. The reverse engineering process may be undertaken by the original manufacturer (OEM) of the product or by some other party such as a licenced manufacturer or the current owner of the product. Reverse engineering may be used in prolonging the life cycle of a product, but also just to create or upgrade its digital design documentation. Just upgrading the documentation is common e.g. in the aviation industry, where the requirements for an up-to-date digital documentation are increasing.

Can the life-cycle of buildings and other constructions be prolonged using reverse engineering technologies as is being done in the manufacturing sector?

Yan:

That sounds very interesting. In the built environment sector, reverse engineering can play an important role in supporting circular economy practices. Many existing buildings, especially older ones, do not have complete digital documentation such as CAD drawings or Building Information Models. This can make renovation, maintenance, or material recovery much more challenging.

By creating digital representations of existing buildings and components, reverse engineering helps us better understand what materials and building elements are actually there. This information can support renovation projects, improve building maintenance, and identify components or materials that could potentially be reused or recycled at the end of a building’s life.

It can also provide the foundation for more advanced digital solutions. For example, accurate 3D models can be used as the basis for digital twins of buildings or even larger urban environments.

I have been involved in two projects at Metropolia that relate to these topics: RADIAL and DigiPurku. The RADIAL project focused on improving digital modelling capabilities in the construction sector, with a particular emphasis on creating accurate As-Built BIM models. DigiPurku, on the other hand, focused on the later stages of a building’s lifecycle, exploring digital solutions for demolition planning, material recovery and component reuse.

In both projects, a process called Scan-to-BIM played an important role. In simple terms, Scan-to-BIM uses technologies such as laser scanning or photogrammetry to capture existing buildings as dense collections of 3D points, known as point clouds.

These point clouds provide detailed geometric information about a building, but they do not yet contain information about what the objects actually are. Through the Scan-to-BIM process, building elements such as walls, doors, windows, columns and mechanical systems can be identified and converted into BIM objects with semantic information attached to them.

The result is not only a more accurate digital representation of the building, but also a richer information model that can support decision-making throughout the building lifecycle. Additional information related to sustainability, material properties, carbon emissions, reuse potential or maintenance requirements can then be linked to the model and used to support renovation, operation, demolition and circular economy strategies.

Lili:
This is very interesting. Creating the BIM models has some similarities with using the reverse engineering process to create the missing or obsolete design documentation in the manufacturing sector. AI is nowadays applied to increase efficiency and innovativeness in many fields. Can it also be used in the construction sector when creating the 3D models?

Yan:

AI is becoming increasingly important in Scan-to-BIM workflows. Traditionally, converting point clouds into BIM models has been a time-consuming and largely manual process. Today, machine learning and deep learning methods are helping to automate parts of this work.

For example, neural network models can perform semantic segmentation on point clouds by identifying and classifying different building elements such as walls, floors, ceilings, doors, and windows. Once these elements have been recognized, AI can assist in generating BIM objects and reducing the amount of manual modelling required.

AI can also help when digital documentation already exists. If a building has architectural drawings, such as floor plans, sections, or elevations, some AI-powered tools can extract information from these 2D documents and support the creation of 3D BIM models.

More broadly, AI is advancing rapidly beyond the large language models that many people know from chatbot applications. Researchers are also developing models that can understand and represent spatial environments, combining information from images, geometry, and physical spaces.

One exciting development is the use of techniques such as 3D Gaussian Splatting, which can reconstruct realistic 3D scenes from collections of photographs. These methods can generate detailed digital representations of existing environments and may support future workflows in areas such as reality capture, digital twins, and Scan-to-BIM.

Taken together, these technological developments have the potential to make reverse engineering faster, more accurate, and more accessible. This could significantly support circular economy practices by improving our ability to document existing assets, identify reusable materials, and make informed decisions throughout a building’s lifecycle.

However, developing new technologies is only part of the challenge. It is equally important to transfer this knowledge and these skills to professionals who work in industry. This brings us to the CircleRedu project. Does CircleRedu play a role in supporting this knowledge transfer? Could you tell us more about the project and its objectives?

Lili:
Thank you for asking! The twin transition creates a demand for new knowledge and skills in the manufacturing and construction sectors. The CircleRedu course is exactly about transferring the knowledge on reverse engineering and circular economy to future and current professionals.

The course has four modules: green skills for the circular economy, tools and technologies for reverse engineering, change management for the green transition and practical cases from the manufacturing sector. The module on green skills includes digital tools for life cycle assessment (LCA), the reverse engineering module also talks about current topics such as how AI technologies may be used in creating 3D models, and the change management module addresses typical barriers for implementing the green transition and underlines the role of the green transition as a driver for innovations.

Could you also tell me about your current research? Is it connected to the twin transition?

Yan:

Thank you for asking. Currently, I’m involved in a Business Finland–funded project called Metadata to Metaverse at Metropolia’s Smart and Creative City Innovation Hub.

The project focuses on developing an open urban platform that brings together digital twins, BIM models, sensor data, and other built-environment information into a shared and interoperable ecosystem. One of the biggest challenges in the real estate and construction sector today is that data is often fragmented across different systems, using different formats and naming conventions. Our goal is to make this data easier to connect, share, and utilize across organizations and stakeholders.

The project is closely related to the Twin Transition, which combines the digital and green transitions. On the digital side, we are building the foundations for interoperable urban data ecosystems by developing standardized metadata models and using technologies such as knowledge graphs to connect 3D models, sensors, and other data sources. This helps maintain clear relationships between building components, assets, and real-time data.

On the green side, better access to integrated urban and building data can support more sustainable decision-making. For example, it can help improve energy efficiency, optimize resource use, reduce emissions, and support sustainable urban development.

Looking ahead, this interoperable platform also creates opportunities for AI applications. AI could help analyze large amounts of urban data, predict energy consumption, detect anomalies in buildings and infrastructure, and support evidence-based decision-making. At the same time, metaverse technologies can provide intuitive and interactive ways to visualize data and explore future scenarios together with different stakeholders.

Reverse engineering may also be closely connected to this work. Technologies such as scan-to-BIM can help create digital models for existing buildings that do not yet have them, providing an important foundation for future digital twins and urban platforms.

This actually connects very well to your course. I think many students at Metropolia would find these topics highly relevant. Could you tell us more about the course and how students can access it?

Lili:
The course will be piloted in selected higher education courses in Finland in fall 2026 and it will be freely available for anyone to complete by the end of the year 2027.
It is great to hear that the course sounds interesting. It has been very enlightening to discuss with you the twin transition in the construction sector and the ACE sectors in general. There are many similarities with the manufacturing sector, and it is fruitful to cooperate and to exchange best practices.

To finish the discussion for today, I will ask you one more question. We have been discussing many important concepts such as the green transition and the circular economy. We have also discussed several processes and tools that can be used in the green transition, such as reverse engineering, digital twins and 3D modelling. Now, based on your experience, what are the most important digital skills and knowledge that a future engineer in the construction sector would need to be able to implement in practice the green transition?

Yan:
If I were to share one piece of advice with students, I would say that BIM and AI are likely to be among the most important technologies supporting the twin transition toward sustainability and digitalization in the construction sector. However, mindset is even more important than the technologies themselves.

For BIM, the key is not the 3D model itself, but the information it contains. Future engineers should think about what information is needed, who will use it, and how it can support better decision-making throughout a building’s lifecycle. BIM is fundamentally about collaboration and data-driven thinking.

AI is also changing engineering practice rapidly. Future engineers will increasingly work alongside AI to analyse information, automate routine tasks, and explore solutions more efficiently. Rather than competing with AI, students should learn how to use it critically and effectively while maintaining their professional judgement.

Another important trend is that the boundaries between disciplines are becoming less clear. Challenges such as sustainability, circular economy, and smart cities require collaboration across different fields. The ability to learn continuously and work in interdisciplinary teams will become increasingly valuable.

Finally, communication remains essential. Engineers need to explain complex technical ideas to managers, clients, policymakers, and users who may not have a technical background. Good communication helps ensure that technology can be understood, adopted, and used to create positive impact.

So, my final message to students is simple: stay curious, keep learning, and be open to working across disciplines. Technologies will continue to evolve, but adaptability, collaboration, and communication will remain valuable throughout your career.

Lili:
Thank you, Yan, for joining me today to discuss the twin transition in the manufacturing and construction sectors.

Yan:
Thank you for the opportunity to participate in this podcast. I hope that the listeners have enjoyed it and got some new ideas regarding the twin transition.

Lili:
I am sure they have. I thank all our listeners. Feel free to share this podcast with anyone who might be interested in these topics. For information on this podcast and on the CircleRedu project, read the podcast description. To receive the latest news on new podcasts and the CircleRedu project, you can subscribe to our newsletter and follow us on LinkedIn. This podcast is licensed under the Creative Commons 4.0 Attribution-ShareAlike.