Crypto twin

Crypto twin

Crypto twin is tokenized
digital twin of a building,
placed in the metaverse
enriched by interaction
with its community.

Let’s build a Crypto twin!

Prvok is the first czech 3D printed building created in 2020. After being constructed and displayed, it became an “artifact of research”, like many other experimental buildings and pavilions do. It contains a large amount of knowledge gained during the process of construction, which we want to share using NFTs. Our aim is to crowd-fund new research by distributing NFTs  to a community of interested researchers and blockchain enthusiasts.


Milestones triggered by ETH balance

We’ll be collecting ETH on a multi-sig address. Once a certain level will be reached a milestone will be triggered.  Each milestone also means an event will take place. […work in progress…]


Bying a CryptoVoxels parcel

EVENT: We’ll throw a small physical/digital party with NFT holders.

10 ETH

Buying a Decentraland parcel

EVENT: We’ll organize a lecture about 3D printing from concrete and about the Prvok building.

20 ETH

Buying a Sandbox parcel

EVENT: We’ll have a Scripting for Metaverse workshop.

50 ETH

Cross-platform shared ownership

EVENT: We’ll organize a meeting across multiple metaverses and the physical space.

100 ETH

Physical/digital conference

EVENT: We’ll host a small conference about bridging the physical and digital spaces.

200 ETH

Finally buying Prvok

EVENT: We’ll become a community which shares ownership of the Prvok building! 

300 ETH

Researching physical/digital bridges

EVENT: We’ll buy more devices to experiment with physical/digital bridges and start a discussion what the future of our Crypto Twin looks like.


We will create an easy to remember amount of NFTs. A vast majority of them, not less than 90 %, will be made available for buying for a psychologically low price around 0.09 ETH. The remainder will be split between the project team and the project treasury to be exchanged for goods and services needed to successfully run the project.
Eth from minting will be used for obtaining metaverse parcels, organizing workshops, buying a real Prvok building and equipping it with technology allowing us to create physical-digital bridge.

Learn more on Discord



Prvok is the first czech 3D printed building created in 2020. After being constructed and exhibited, it became an “artifact for research”, like many other experimental buildings and pavilions do. It encapsulates a large amount of knowledge gained during the process of construction, which can be shared with the AEC community using blockchain technology. Our aim is to crowd fund new research applied to the Prvok building, by distributing NFTs (non-fungible tokens) to a community of interested researchers and enthusiasts. The Non-Fungible tokens represent part of the building but also have a governance utility in terms of the physical artifact itself. Within the paper we describe the crypto-economics mechanisms applied to Prvok, the technical tooling needed in terms of blockchain and smart contracts, and speculatively discuss governance of the artifact.

What is Prvok?

In the czech language Prvok means protozoa and the whole shape of the building is inspired by its shape. Concrete 3D printing is suitable technology to build such complex double-curved walls. The majority of walls of the Prvok building is 3D printed, a middle connecting part is made out of wood. It has a living room with a kitchen desk, bedroom and a bathroom totaling 43 square meters.

What knowledge was created while building it?

The intent of building the Prvok was to showcase the current state of 3D printing from concrete. In order to 3D print using concrete a system of transportation, mixing and pumping and delivering the concrete mixture has to be set up. Using a crane the material was mixed with water in the M-tec mixer and then pumped through a hose to a nozzle attached to the robot’s tip. An industrial ABB robot IRB6700 was used for the printing, its trajectory was generated by a Grasshopper script. Construction team first printed wall segments and tested geometry shapes and material characteristics. It turned out that undulating geometries have a higher chance of being successfully printed without collapse. Smooth and flat walls with a small base have a high chance of failure. It is caused by fresh material of the bottom layers that cannot withstand the pressure of following layers. To prevent it, the whole shape has to be divided into approximately 500 mm high segments, which are printed separately, giving the concrete more time to set. Material for concrete printing contains many additives, which are sensitive to weather changes. If the temperature is too high, extruded material is too dry and cracks, if temperature is too low, material is too liquid and the whole print may collapse. This is why printing was done in a controlled environment of a warehouse in the city Budweis.
To ship the building to Prague, it had to be split into four parts: roof, two printed segments and a middle wooden segment. The wall segments had a steel base, which was needed to support the structures during transportation. After assembly in Prague, finishing processes took the longest time. One of the greatest problems was found in discrepancies between the 3D model and the final print. In many places the printed shape had even 50 mm of difference towards the 3D model. This led to assembly issues with prefabricated parts on site. Such knowledge and guidance will be included in the project NFTs. 

NFT utilities

1. Building shared treasury to fund operation of the project
2. Governance over community decisions
3. Disseminate knowledge about 3D printing and reward the initial creators
4. Partial ownership of the Prvok building with a possibility of forming a DAS
5. Partial ownership of metaverse parcels which enables NFT holders to experiment
6. “Tickets” to events and opportunity to organize own events

NFTs are designed to have multiple purposes. First one is to collect resources for the project to operate. All owners will be incentivised to develop the project, because they are invested in it. That is closely connected to its second function, the governance. Each token will represent one vote on community decision making. By buying more NFTs, one can increase his or her voting power in the community decision making. The current Crypto twin project operates with the research artifact called Prvok and it has defined milestones, but when it reaches the end, the community may propose and vote upon further development of the project. The NFT itself contains a link to decentralized file storage. Here only owners can access knowledge about the concrete 3D printing, how Prvok was built and how setbacks were overcome. Apart from learning how the Prvok building was constructed, the NFT owner also gets access to a Grasshopper script which can be easily repurposed to 3D print different shapes. This way the creators still keep their intellectual property rights, yet they can monetize the effort put into research and development of the building phase. This could be interesting to compare with classical knowledge/science dissemination channels where the economic model is widely different. (Researchers pay money to publishers for spreading their [precious] knowledge.) Such a business model could be further developed for other use cases and it can potentially include even businesses, not just individuals. Each NFT token also represents partial ownership of the physical Prvok building. If the community is healthy enough and proves to the overarching DAO running the whole project that it can operate on its own, it could potentially become a research independent DAS and continue however it likes. Another function of the NFTs is to provide access to metaverse parcells which will be bought in the early project phase. It is similar to the shared ownership of the physical Prvok building. An innovative business model can be derived from the current scarcity of metaverse parcels which elevates their prices. They  are considerably high for an individual to invest in without a clear business plan which would generate return on the investment. That’s why a shared ownership model can be more successful with a strong community. Also, the aspect of spreading good word about such a project into further communities is of crucial importance to the project. In order to be a success, the project needs to build a community of people interested in similar topics which can be tested and experimented upon using the physical structure and the metaverse virtual twin. One last explicit function of the NFT is to enable owners to participate in social events which will take place in both the physical building and the metaverse parcels every time a project milestone is reached. Owners could potentially even organize workshops, lectures and small conferences if the community agrees on that. 

NFT contents

1. Animated 3D model in .glTF format
2. 3D printing from concrete workbook in .pdf format
3. Rhino model of the control surface for the Prvok building in .3dm format
4. Grasshopper script for generating robot code to 3D print in .ghx format

In order to make the NFTs attractive to a bigger set of the crypto community and therefore secure a big enough community, the content and visual appearance has to be innovative as well as the use cases of them. Currently the most popular NFT marketplace OpenSea enables showing 3D models even with an animation. Most of the animated NFTs are still using .mp4 video and then provide a separate 3D model file using .glTF format usually. Using a 3D file with native animation will be a small innovation, yet it is useful for depicting the process of 3D printing a structure with a robotic arm. Aiming at original yet engaging and innovative NFT might be beneficial in getting quickly recognised in a flood of other NFT projects. Alongside the main animated 3D model, which serves as an advertisement and “facade” of it, the NFT contains hashes of Grasshopper script and Rhinoceros .3dm file containing the Prvok building production model. The script can be quickly repurposed for printing other objects. This is a big difference from other NFTs, where the creator keeps the knowledge of creating the NFTs and other products private. Such a move, when properly explained to the community can be also a big advantage in terms of trust and credibility of the project. 

Milestones and Project Timeline

While the sales of NFTs generate value in project treasury, according to previously disclosed levels reached, milestones will occur. The first three milestones will trigger buying virtual land in the most promising metaverses. The initial levels of gathered resources are intentionally set as low as possible in order to reach them early in the project development. This will help with dissemination of the idea and fulfill one of the promises to the community very soon in order to gain even more attraction. By securing a few parcels in different metaverses and placing a recognisable 3D model of the Prvok building there, the first promise of shared ownership of metaverse parcels will be kept. NFT holders can already use and change the content of the parcels and use their NFT voting power to govern the decisions collaboratively. Tokens also represent tickets to attend or even organize workshops and lectures happening in these virtual spaces. Next comes a longer more resource oriented phase consisting of another two or three milestones. These are promoting physical-digital events taking place in metaverses and at the same time in the Prvok building which is still being rented for such purposes. These events will engage with the growing community and spread the lessons learned so far as well as provide opportunities for initial experiments with physical-digital interactions between real-world space and the co-owned metaverse parcels. The outcomes of such events will be used in further promotion of the project on social media and crypto-friendly spaces as well as the metaverses. The next milestone shall be triggered once enough resources to buy the real-world building will be gathered on the project’s treasury. Since the sales of NFTs and the treasury size is publicly written on the chain, every potential NFT buyer can check how well the project performs so far and these key statistics can be shared in regular project updates on social media. Another key factor in the treasury growth are gains from secondary markets where NFTs can be traded which provides royalties of 3% from each sale. Once this milestone is reached, a significant legal issue has to be addressed. SInce the prvok building is legally a livable sculpture transferring its possession to a crypto-enabled legal structure of the ArchiDAO will be less complicated than if it was a real estate. The last milestone will trigger buying more technology for bridging the gap between physical and digital domains. These will include but are not limited to projectors and touchscreens, sensors, microcontrollers and cobots.

Tokenomics and Incentives

We will create an easy to remember amount of NFTs. A vast majority of them, not less than 90 %, will be made available for buying for a psychologically low price around 0.09 ETH. The remainder will be split between the project team and the project treasury to be exchanged for goods and services needed to successfully run the project. Eth from minting will be used for obtaining metaverse parcels, organizing workshops, buying the real-world Prvok building and equipping it with technology allowing us to create physical-digital bridge. All tokens can be sold on secondary marketplaces, like LooksRare or OpenSea. NFTs offer a feature of paying a portion of each trade back to its original creators. This royalty fee is very common and represents another stream of revenue for the treasure. Projects can collect more revenuemoney and holders are incentivised to be part of a constantly growing treasury. Another valued characteristic of NFT tokens is the fact you can burn them. Burning mechanism removes the token from circulation, making it a deflationary asset. Burning mechanism might be implemented when the owner of a token asks for a service from the community. Instead of paying each member an amount of money, the owner may burn its own token, therefore remaining ones gain on value. In our case burning will occur, when a community member would like to organize an event in real Prvok, or just book it for himself. Each token is unique and displays the printing process of Prvok. This may incentivise collectors to collect more tokens containing unique information. NFT ownership makes you partial owner of projects treasury, therefore you become partial owner of metaverse parcels and physical Prvok building.

Difference between digital twin and crypto twin

Crypto twin basically refers to the tokenized digital twin of a building, placed in the metaverse. This improves its functionality on many levels and therefore a new framework should be developed for it. Letting the community buy NFTs linked to the project secures additional financing for it. Decentralized metaverses are easy to access with a regular laptop using a web browser and metamask extension, no additional software needed. This allows much more users to enter a virtual building and even interact between each other, compared to viewing a model in VR. This interaction level between users is mainly missing in a digital twin model. Analyzing interaction can provide great feedback for improving building design and after several iterations in the metaverse, a tested model can be constructed. The community can also provide feedback on the building design, even before it is constructed. This paper is investigating possible features and necessary functionalities of a crypto twin set up and therefore is built on top of an existing building of Prvok. In other cases building a crypto twin metaverse part can precede the actual real world construction. There is a question of what happens with token holders, when a building is constructed. Tokens might represent partial ownership of that building, therefore they can earn revenue from just holding it. By burning it you could unlock more possibilities. Even after construction is finished the crypto twin is still viable. Events happening in the real building may be reflected into the metaverse. For example a concert hall could earn extra revenue from an event by having its crypto twin. It would allow more people to attend and lessen the environmental impact of long traveling to visit these events. The crypto twin could sponsor facility management and maintenance costs of the real building. Tokenized parts of the building can contain information about amounts of used materials.