SemanKit City platform project revolves around the conversion of BIM data into semantic web content, for the purposes of achieving circular economy urban materials exchange. The project consists of research of state-of-the-art developments in the semantic web modular approach, BIM plug-in and web-site prototype – www.semankit.com. As the creator of the internet Tim Berners Lee suggests in the semantic web:

information is given well-defined meaning, better enabling computers and people to work in cooperation”.

Hence, the semantic web approach allows us to establish user-side operations and city-wide application based on multi-layered material data and accurate user-centric search results in the local urban repository. In addition, the semantic web BIM development allows for building-to-building sophisticated operations, AI implementation and many other flow-on processes that make the concept of circular economy and digital twinning possible in practice.

The current research project suggests User Interface using Revit addon in which designers, manufacturers and owners can publish building material components to recycle, reassemble, reuse, or repurpose, enforcing the philosophy of circularity in the built environment. The published materials get uploaded in the cloud www.semankit.com – from where other AEC professionals can choose them based on highly detailed criteria search such as carbon-footprint impact, material properties, cost, vicinity, and any other parameters as well as their complex interdependencies.

In SemanKit – the Circular economy concept and Semantic BIM data are entangled with Digital twinning by transfer and exchange of maintenance data. The objects in the platform carry not only geometry information in .ifc/ .fbx/ .rvt files, but also meta-data in linked knowledge graphs, which will be constantly increased by multiple co-authors. The objects on the platform will have a constant data influx that describes the life – exploitation/ performance/ maintenance of each individual element. This is achieved by the SemanKit web-site architecture and modular ontological approach versus all-encompassing ontological approach. The modularity ensures the future data repository flexibility of the project and growth – not only in terms of elements typologies/ industries, but also as a digital twinning data stock exchange. SemanKit City Legislative Framework and Material Passports is also part of the project proposal to further incentivize the digital twin data sharing from the owners and the constant data influx of maintenance data from the users of the building components.

The future development and research of the project would also investigate the BIM interoperability options through OPEN BIM standards use.

Circular Economy

The Global population continues to grow rapidly, increasing demand for raw materials, while supplies are decreasing. The governments’ are therefore working with industry to ensure that by 2050 the economy will run entirely on reusable materials. In this circular economy, there will be no more waste, as resources will be reused again and again.

Circular economy as a principle denies the end-of-life of all materials and consciously enforces the reuse, repurpose and recycle of every resource.

Linear consumption is reaching its limits. A circular economy has benefits that are operational as well as strategic, on both a micro-and macroeconomic level. This is a trillion-dollar opportunity, with huge potential for innovation, job creation, and economic growth.

The last 150 years of industrial evolution have been dominated by a one-way or linear model of production and consumption in which goods are manufactured from raw materials, sold, used, and then discarded or incinerated as waste. In the face of sharp volatility increases across the global economy and proliferating signs of resource depletion, the call for a new economic model is getting louder. The quest for a substantial improvement in resource performance across the economy has led businesses to explore ways to reuse products or their components and restore more of their precious material, energy, and labor inputs. A circular economy is an industrial system that is restorative or regenerative by intention and design. The economic benefit of transitioning to this new business model is estimated to be worth more than one trillion dollars in material savings.

A circular economy is an industrial system that is restorative or regenerative by intention and design. It replaces the end-of-life concept with restoration, shifts towards the use of renewable energy, eliminates the use of toxic chemicals, which impair reuse and return to the biosphere, and aims for the elimination of waste through the superior design of materials, products, systems, and business models.

Such an economy is based on a few simple principles, as shown in the illustration.

First, at its core, a circular economy aims to design out waste. Waste does not exist: products are designed and optimized for a cycle of disassembly and reuse. This tight component and product cycles define the circular economy and set it apart from disposal and even recycling, where large amounts of embedded energy and labor are lost. Second, circularity introduces a strict differentiation between consumable and durable components of a product. Unlike today, consumables in the circular economy are largely made of biological ingredients or ‘nutrients’ that are at least non-toxic and possibly even beneficial, and can safely be returned to the biosphere, either directly or in a cascade of consecutive uses. Durables such as engines or computers, on the other hand, are made of technical nutrients unsuitable for the biosphere, such as metals and most plastics. These are designed from the start for reuse, and products subject to rapid technological advances are designed for an upgrade. Third, the energy required to fuel this cycle should be renewable by nature, again to decrease resource dependence and increase systems resilience.

Building Flexibility is important and is defined as the ability of the building to change in order to adapt to the changing situations. We would design in such a way that our buildings will be flexible and easy to adapt and we also need an underlying system that will help us achieve that.

One of the major shifts that would happen when we start shifting towards a circular economy mindset is the so-called Product-as-a-Service, which would affect also a lot of our design and construction realities. For example, instead of owning a facade, a user would be able to rent it out. Cloud or centralized resources will help us manage this process.

To make a circular economy possible, a number of legislative changes will need to be taken into consideration. One of the main aspects is that all buildings will need to have some form of digital materials passports, aiming to be a one-stop-shop for material information. Material passports are sets of data describing defined characteristics of materials in products that give them value for recycling and reuse.

Digital twins

The concept of the digital twin is to have a replica of an existing physical asset in digital form. The twin could be anything, a person, equipment, a building, a city, a forest, or a planet. The detail in terms of the representation depends on the purposes of the digital twin since we could use 3D scanned point clouds as a form of a digital twin or actual 3D BIM models when we talk about buildings. LOD 500 BIM model is supposed to be the exact digital replica of the physical asset, but this is still not a digital twin, because the concept of digital twinning is related to adding a layer of data describing the life & occurrences that are happening to the physical objects. For example, if we talk about a door, we have our BIM model uploaded in the cloud and sensor for the opening and closing of the door, this sensor sends data each time the door has been opened and this data is collected in a database. So, we could see day by day how many times the door has been opened and who entered if there is an ID card sensor to it.

A major issue related to the digital twinning concept in practice is that the gathered data is usually stored by its owner and the sharing of the data is limited, hence the capitalization of the digital twin data-gathering potential is still in its infancy. As we all know that data is the new gold, we need to discover ways of unlocking the interoperability and democratic exchange of digital twin data.

Semantic technologies are well-known to be suitable for resolving the interoperability problem of heterogeneous and distributed systems. Whereas there are many ontology-based approaches to deal with domain-specific data, the interoperability among different data sources is still an open research topic. In this research, we will present the ideas and benefits of exploiting semantic technologies not only for mastering the interoperability and mixture of multi-domain data, but also provide a new level of services to achieve the greater potential of circular economy applications.

Semantic web

In our research and also stepping on the knowledge and research of other acknowledged professionals in the field, we have come to realize that one of the main issues in the Semantic web ontological approach is that a single ontology is never enough or is always too much. Let’s take a look at IfcOwl ontology which is based on the IFC schema. It has way too many classes and properties sometimes, in other instances it is missing on properties such as historical aspects, ecological, Operation and Maintenance, and others. There are many other ontologies that do describe historical data, OM, and ecological data. So the right way forward is not to seek to create ontologies for AEC that are all-encompassing, but rather use small ontologies and link them to create adequate data flow for the specific construction elements.

Research questions


We believe that the answer to all previous questions could be hidden in the formulation of a new Circular Economy City Framework. For our project, we have created a new model which is based on a Centralized city database storing semantic information and possibly also physical storage space. The way it works is we are starting from the creation of a BIM model or digital twin, which is usually commissioned by the developer/ owner of the building, in that model all the information related to design and construction is being stored. This same model becomes part of the building material passport. It is published to the city data repository and in return, the owner is getting certified as well as taxed with incentives for carbon and sustainable materials, reused or recycled materials. As the building gets into operation – the Owner, the Facility managers, the tenants also gather information for the digital twin and instead of deleting this data they create a link in the city repository and receive incentives for doing so. At some point, the building would be demolished and all elements in the city repository become available for reuse/ repurpose or recycling. Through a website and Revit plugin, other building professionals can browse, select, claim and buy the materials for their new projects.

SemanKit website prototype

Semankit prototype consists of website with a semantic database with catalog of URIs or building elements that are being published to the web from the users using a Revit plug-in. Then we use the possibility of RDF to define statements of statements without revealing the content. In this way, we are not building an all-encompassing ontology but allow external users to add new URIs with semantic and non-semantic information based on an object with a unique city ID. Our proposal is to keep the city database as light as possible with very basic info about the objects and the additional information to be stored on FTP servers, virtual machines, cloud on the user side owning and managing the building

By using SPARQL users can ask very sophisticated questions and query this data. For example, list the reusable windows with a certain size in a 10 km radius or list a door model that has been opened 100000 times. The way we query the semantic information gives us a lot more accurate results and hence we can build on it a lot more sophisticated applications instead of the usual search algorithms we use today.

Prototype BIM-to-Web and Web-to-BIM workflow

In terms of technologies used for our prototype, we used Dynamo and created scripts for each command, we used the Data shapes package to get forms for the user to interact with, we used Dyno to create a Revit plug-in ribbon. Dynamo was sending data to Dropbox from where we used Zapier to automate the upload of information directly on the website without any manual work. For the website, we used as design tools Webflow and WordPress for the semantic catalog and database. The reason we chose WordPress is that there are a lot of new plug-ins coming up constantly for the AI and automated semantic enrichment of meta-data and common text. One such plug-in we used is WordLift.

BIM Prototype

The Revit addon has 4 sections – BIMKIT, SEMANKIT, LINKIT and WEBKIT. Through this ribbons the users interact with the cloud city database, view and edit BIM and semantic data and publish and receive geometry and meta-data.

Through the Revit plug-in BIMKIT functionality a user assigns the circular economy phases to all the elements and after that publishes them with the LINKIT. The element gets exported to Dropbox with fbx, rvt, ifc formats, image representation, and meta-data. Zapier sends all of this information to the web and with the parser, the data is converted into semantic content. On the web then the user can view the metadata, the 3D model, image, and additionally added semantic data. Users can add more semantic data both through the website and the plug-in for each element throughout the life of the element.

Other users query the city repository through a SPARQL web end-point and specify what characteristics are of interest. For example, the user can find a slab for recycling that is below 250 sq.m. and is located in Canberra. After this detailed query, the user receives results with a unique city ID for the elements, if there are multiple slabs that respond to this query, the user will get a list. Once the user has chosen the element, he/she wants to use – clicks on the receive button and types in the city element ID. After a short loading period, the claimed element gets located in the Project origin of the Revit file.

If a user has a digital twin model that is so to speak living and constant data is being gathered. The user can directly add tabular or semantic data for a certain element based on the unique city ID. The user can click and view the semantic data currently available online. By clicking on edit semantic data, the user can add a new URI which contains additional semantic information. For example in this way Facility managers can constantly upload OM data for various components instead of deleting it and receive tax incentives.

In the Semankit future

We believe that Tim Berner’s vision for the Semantic web will make the internet not only machine-readable, in AEC it will enable our buildings and cities to exchange data and resources intelligently, facilitating the circular economy development.

SEMANKIT CITY is a project of IAAC, Institute for Advanced Architecture of Catalonia developed in the Master in Advanced Computation for Architecture & Design in 2021 by Polina Hadjimitova & Sachin Dabas

Faculty: David Andres Leon