Reformative Coral Habitats | Reef Tiles

Reformative Coral Habitats | Reef Tiles
Rethinking Artificial Reef structures through a robotic 3D clay printing method.

Project Credits:
Robotic Fabrication Lab | Faculty of Architecture | The University of Hong Kong
Christian J. Lange (Team Leader)
Lidia Ratoi
Dominic Co Lim
Jason Hu

Swire Institute of Marine Science (SWIMS) | The University of Hong Kong
David M. Baker, Ph.D. (Team Leader)
Vriko Yu
Phil Thompson

The coral restoration project is a collaborative research mission between the Robotic Fabrication Lab, Faculty of Architecture, and the Swire Institute of Marine Science, both at The University of Hong Kong. The project is commissioned by the Agriculture, Fisheries and Conservation Department (AFCD) and is part of an ongoing active management measure for coral restoration in Hoi Ha Wan Marine Park in Hong Kong. Hoi Ha Wan Marine Park accounts for more than three quarters of reef building coral species in Hong Kong, and is also a home for more than 120 reef associated fishes. However, gradual deterioration by bio-erosion over the years, coupled with bleaching and mass mortality events in 2015-2016, are putting local coral community at risk. Hence, a team of marine biologists and architects has developed a series of reformative 3D printed terracotta reef-structures intended to aid coral restoration by providing structurally complex substrates at a degraded area.

Historically, artificial reefs are made from pollutants-leaching materials (e.g. plastic/concrete/metal) and now transformed into environmentally friendly materials (e.g. ceramic and terracotta). The project team from HKU uses 3D printing technology to engineer structures that can be customized for specific locations with different environmental challenges (e.g. sedimentation), thus enhancing the ecological restoration success.

The 3D printed reef tiles are designed to prevent sedimentation build up, which is one of the major threats for corals. A tailored algorithm was used to print the biomimicry patterns integrated with spaces for securing coral fragments. The production of the 128 pieces of reef tiles with a diameter of 600mm, covering roughly 40 sqm in total, was finalized in early July of 2020. They were printed through a robotic 3D clay printing method with generic terracotta clay and then fired at 1125 degrees Celsius. The design was inspired by the patterns typical to corals and integrated several performative aspects addressing the specific conditions in Hong Kong waters. The 3D printed reef tiles have been deployed in July 2020 at three selected sites within the park which include Coral Beach, Moon Island, and in a sheltered bay near the WWF marine life education center.

This pilot study aims to investigate the restoration success using mono-, mix- and polyculture of three coral species, namely AcroporaPlatygyra, and Pavona. The three selected species display different strategies, representing the historical, current, and future dominant candidates in the park – Acropora, commonly known as staghorn corals, are fast growing making them a competitive species for space; Platygyra, as known as brain corals, are adaptive to thermal stress, yet suffering from bio-erosion; and Pavona, the leaf coral, with the unique plate-like growth form are adaptive to sedimentation. The project team collected corals of opportunity, which are dislodged coral fragments that are unlikely to survive given no human intervention and given these coral fragments a second chance to thrive. The coral fragments have been outplanted in July 2020, and the experiment will be monitored for the coming year.

The researchers hope that this new method for artificial reef tiles will help to restore corals and conserve biodiversity more effectively and become a vital contribution to the ongoing global efforts to save the degraded coral reef systems in metropolises.

Completion Year:  2020

Location: Coral Beach, Moon Island, and the WWF marine life education center, Hong Kong

Built Area (m2):  ~ 40 sqm

Funding body:  AFCD

CeramicINformation Pavilion

CeramicINformation Pavilion
Rethinking structural terracotta bricks through robotic 3D printing technologies

Project Leaders: Christian J. Lange, Donn Holohan

Research Assistants: Mono Tung, Kristy Chow, Pamela Maguigad

The Fabrication and Material Technologies Lab of The Faculty of Architecture at The University of Hong Kong has recently finished its second robotically manufactured intervention called “CeramicINformation Pavilion.”

The project is part of an evolving series, which aims to reconcile the material intelligence of vernacular crafts with the specificity and flexibility promised by digital design and fabrication technologies. This particular iteration explores the process of construction, and seeks to find an appropriate level of automation suitable for emerging and transitioning economies.

Each of the approximately 1000 components that make up the experimental structure is unique and has a specific immanent relationship to its neighbors. This approach allowed the complex construction to be realized using unskilled labor, over a short period, without the need for typical architectural drawings. 

As a point of departure, this project examined the ubiquitous terracotta brick – common in modern Chinese construction, and explored it’s potential re-shaping through the process of robotic 3d printing. Approximately 1.5million lines of code were generated – with each brick containing an average of 1400 individual target-points.

The bricks were manufactured over a period of 20 days before the lightweight elements were shipped to the site and assembled into the multifaceted wall. The project not only highlights the new possibilities for architectural expression, but also the capacity these systems have to change the way in which we fashion the built environment.

The project was part of the 2017/18 Bi-City Biennale of Urbanism and Architecture (UABB) in Shenzhen, China.

Completion Year:  2017

Location: No. 82 East Zhongshan Street, Wanli Industrial Zone, Nantou Old Town, Nanshan District, Shenzhen

Built Area (m2):  3 sqm

Funding body:  UABB Shenzhen

Ceramic Constellation Pavilion

Ceramic Constellation Pavilion
Spatial shifts through robotically fabricated terracotta bricks

Project Leaders: Christian J. Lange, Donn Holohan, Holger Kehne

Research Assistants: Tony Lau, Anthony Hu, Teego Ma Jun Yin, Ernest Hung Chi Lok, Chau Chi Wang, Ren Depei, Mono Tung, He Qiye, Henry Ho Yu Hong

Workshop students: Go Yi, Sisay Sombo, Cheung Hoi Ching, Cheung King Man, Cheung Pak Yin , Ho Pui Lun, Verena Leung , Sharon So Cheuk Ying , Xu Junjie, Zhao Jinglun, Sampson Ip Cheuk Sum, Tan Shaoying, Yeung Tsz Wing

The Fabrication and Material Technologies Lab of The Faculty of Architecture at The University of Hong Kong has recently finished its first robotically manufactured intervention called “Ceramic Constellation Pavilion.”

The Pavilion, which was built by researchers and students utilizing robotic technology, is the first outcome of a new collaboration between The Faculty of Architecture at HKU and Sino Group.  The research initiative that supports arts, cultures, and technology is intended to foster cultural awareness of new technologies for the built environment.

In a context that has been largely shaped by standardization and mass production, the project seeks to overcome the constraints of today’s architectural production through the introduction of a structure made entirely of non-standard components.

This inaugural workshop of the “Sino Group Robotic Architecture Series” utilized terracotta clay to test the possibilities and limits within robotic fabrication and to revitalize a material system that has a significant tradition in Asia.

Departing from traditional brick bonds, the 3.8m tall project articulates a load-bearing composite structure with timber – where each of the nearly 2000 3d printed terracotta bricks is unique and different, enabling varying degrees of transparency, morphological shifts, and new experiences.

Around 700 kg of raw terracotta clay was printed over a period of 3 weeks into individual bricks that were then fired at 1025 degrees Celsius. With 2-3 minutes average printing time for each brick, the pavilion is one of the first of its kind in the world that incorporates this specific material system.

All components were fabricated with the equipment in the newly fitted Robotics Lab at HKU’s Faculty of Architecture and assembled during a ten-day workshop by students from the Department of Architecture.

The project was on show from June 19th to July 6th 2017 in the North Atrium of Olympian City, West Kowloon.

Completion Year:  2017

Location: North Atrium of Olympian City, West Kowloon, Hong Kong

Built Area (m2):  2.5 sqm

Funding body:  Sino Group

Structural engineers:  Goman Ho & Alfred Fong – Ove Arup & Partners Hong Kong Ltd


Wind and Rain Bridge

Wind and Rain Bridge
Covered Walkway, Shelter, and Meeting place

Project Team: Jiang, Hejia (Team Leader) Man Ho Kwan, HKU Architecture Students
Funding body: Supported by the Gallant Ho Experiential Learning Fund, HKU
Design: Donn Holohan / the University of Hong Kong

This project seeks to offer an alternative mode of community redevelopment that references local crafts and traditions, and utilizes sustainable materials and methods, to create both social and physical infrastructure. Critical to this process is the integration of digital design methodologies, which allow for the planning and testing of complex assemblies. The high level of training and labor associated with these assemblies has been a barrier to the continued viability of complex, long-span, timber structures in China and other developing and transitioning economies.

Situated on the outskirts of Peitian Village, Fujian Province, China and designed to be constructed without the use of mechanical fasteners, “Wind and Rain Bridge” is a reciprocal interlocking timber structure which draws on the long tradition of wooden buildings native to the region. Each of the bridges’ 265 elements is unique and integral, assembled under the supervision of traditional carpenters, who number some of the few remaining exponents of their craft.  Central to this project is the idea of reciprocity, the bridge uses relatively short elements to build a structure with a span longer than its’ individual parts – where each beam is supported, and supports other beams in the structure. This structural system is generated to fulfil a spatial and social agenda, yet simultaneously the way in which the project is constructed underpins and informs these attitudes.

The bridge is constructed from locally sourced, sustainable timber. It is designed to achieve its’ relatively long span without the use of metal brackets, supports or mechanical fixings. This severe restriction, inspired by vernacular architecture ultimately led to the design of a complex jointing system, which harnesses timbers’ hydroscopic qualities -the expansion of the timber elements in reaction to its environment compresses each of the dovetailed joints which make up its superstructure.

Project Information

Supported by the Gallant Ho Experiential Learning Fund, and integrated within the University of Hong Kong’s introduction
to architectural design course, The Peitian bridge project took 70 students to southern Fujian to aid in the construction
of this community structure.

Location: Peitian Village, Fujian Province, China

Construction: Peitian Community Craftsmen

Size: 20 sqm


Project Title: NEW ORDERS, in search of a new point-block diagram for Hong Kong

Project Team: Olivier Ottevaere (PI)


The project explores a series of alternative structures for housing through a design-research prototyping process. Nine proto- structures are developed through the conception and realization of columns cast in concrete. The series explores specific structural principles at 1 to 1 scale, which are further architecturally tested as speculative towers for urban living at 1 to100 scale.

At 1 to 1 scale, an empirical approach is adopted for the making of the columns. Concrete as process rather than just concrete as material sets the main methodology for the design-research. Trial and error experiments, closely related to the properties of the material (liquid to solid formation), seek to put forward new techniques of formwork design and construction procedures that are more flexible and more sustainable.

Design analysis, informed by the work of the early ‘structural rationalists’ (E. Torroja, F. Candela, P.L. Nervi, H. Isler, R. Maillard, E. Dieste, et al.), considers the transformation of structural languages in an attempt to revive an architecture for vertical living (point-block).

While these structural mavericks took reinforced concrete to the limit of what the new material could do both structurally and spatially, their pioneering work responded, for the most part, to lower building scales and to singular programs (i.e. civic, cultural, religious); all but Housing. The research revives the dialogue in the context of high density Asian living. The dialogue is being pursued with new technology that breaks the homogenizing influence of concrete.

The modernist search for concrete-based new models for living, fuelled by an urgent need for cheap housing after the world war destruction, was devised in Western Europe in the form of a cast-in-place skeleton frame. This flexible column-slab system was first patented and universally distributed by the ‘Hennebique’ enterprise in the late 19th century and later, in 1914, generalized by Le Corbusier as the Dom-ino protocol (domus-innovation). Its promise was social; to support individualization of living spaces by internally liberating the plan of a building from its structural imperatives (‘Free plan’). A century later, this now ubiquitous structural system has largely achieved the reverse: mainly creating an order characterized by homogeneity based on the repetition of the same living units across building scales.

The design-research aims to develop new structural articulations for high-rises that are more agile in negotiating the transition from one kind of program to another within a complex. These aim to provide residents with gradients of communal spaces that reconcile (semi-) outdoor living issues in a sub-tropical climate.
One of the overarching research propositions is to reassert structural design and construction procedures as the main driver for new Housing organizations in a way that helps break from the monotony of current systems.


Journal publication

  • 2016: “New Orders, In search of a new point-block diagram for Hong Kong”, Ottevaere O., GSTF Journal of Engineering Technology (JET). Vol.4, No.1, (Print ISSN: 2251-3701, E-periodical: 2251-371X).
    Conference papers
  • 2016: “New Orders, In search of a new point-block diagram for Hong Kong” (Peer-reviewed paper), Ottevaere O., 4th Annual International Conference on Architecture and Civil Engineering (ACE 2016), Singapore.
  • 2016: “Liquid State and Concrete Uncertainties” (Peer-reviewed paper) Ottevaere O., in Risk Panel, International Research Based Education 2016, in celebration of the 175th Anniversary of the Bartlett School of Architecture, University College London (UCL), London, England.
  • 2016: “New Orders, In search of a new point-block diagram for Hong Kong” (Peer-reviewed paper), Ottevaere O., 3rd International Conference on Structures and Architecture (ICSA 2016), Guimaraes, Portugal.
  • 2016: “New Orders, In search of a new point-block diagram for Hong Kong” (Peer-reviewed project), Ottevaere O., Cross-Americas: Probing Disglobal Networks, Association of Collegiate Schools of Architecture (ACSA) Annual Meeting 2016, Santiago, Chile.


  • 2015 Bi-City Biennale of Urbanism/Architecture, Hong Kong Lecture
  • 2016: “Concrete as Process”, Advanced Technology Lecture Series: Technology and Material, American Institute of Architects (AIA) Hong Kong Chapter.
  • 2015: “Cast-in-Space, in search of New Procedures of Making”, School of Architecture, The Central Academy of Fine Arts (CAFA), Beijing, China.
  • 2015: “Liquid State and Concrete Uncertainties”, Practice Research Symposium (PRS Asia), Royal Melbourne Institute of Technology (RMIT), Ho Chi Minh City, Vietnam.



MEDUSA, Making Ways and Ways of Making

Project Title: MEDUSA, Making Ways and Ways of Making

Project Team: Olivier Ottevaere (PI)


Medusa is a full scale built prototype for an umbrella structure, providing shade for public use.

Three interlocking concrete legs describe a central void and articulate a continuous transition from column to slab; an alteration of a mushroom column archetype.

The prototype reinterprets Felix Candela’s umbrella projects with radically different formwork methods, responses to material properties and construction procedures.

The fabrication of the project explores means of conceiving concrete formworks that are more responsive and adaptive to the casting process by exploiting the short lived gap between liquid to solid. In doing so, the formwork is constructed from a range of materials, hard and soft, all accomplices in interacting with gravity loads, pressure and water seeping.

On making ways: With a group of architecture students, we took residency in a large precast factory in the Pearl River Delta, a region of China often labeled the ‘the factory of the world’. There, for three weeks we lived and worked with factory workers, learnt from their various trades and fully experienced how such a plant, geared towards mass production of precast elements, operates professionally but also socially. By meeting half-way in the realization of the prototype, productive working relationships were forged between students and factory workers, at each stage of the process.

On ways of making: The temporary formwork was constructed upside down to make full use of gravity. After curing, the concrete prototype was flipped in its intended position. The main intention for the project was to influence the process of architectural design in reverse; that is by synthesizing an architectural proposal from the findings emerging out of a succession of built experiments. Throughout a trial and error process, geometry is employed as regulator of a short lived liquid mass in space and not as form making. During the casting process, geometry orchestrated the different interactive roles, given to each elements of the formwork, until a solid formation was finally reached.

Research output


2016: “Medusa, Making Ways and Ways of Making” (Peer-reviewed project), Ottevaere O., in  Material and Media Investigations Panel, “Shaping New Knowledges”,  Association of Collegiate Schools of Architecture (ACSA) Annual Meeting 2016, Seattle, Washington, USA (

2016: “Liquid State and Concrete Uncertainties” (Peer-reviewed paper) Ottevaere O., in Risk Panel, International Research Based Education 2016, in celebration of the 175th Anniversary of the Bartlett School of Architecture, University College London (UCL) and in collaboration with the Association of Architectural Educators (AAE) and the Architectural Review (AR), London, England (


2016: “Concrete as Process”, Advanced Technology Lecture Series: Technology and Material, American Institute of Architects (AIA) Hong Kong Chapter.



Project Title:  LINE ON FIRE, or the materialization of a line in motion

Project Team: Olivier Ottevaere (PI)


This ongoing research project makes use of ruled based geometry to prototype volumetric formworks for concrete casting.
The main design-research tool is a custom made automated 5-axis hotwire cutter.

Volumes of revolution are defined by a line moving in space.

From the input of different 2d profiles, a burning line describes volumes of changing sections from 4 automated translations and 1 rotation.
By inputting specific protocols for synchronized motions, new topologies emerge described by time and movement. These are further employed to create part-moulds from EPS foam blocks for thin shell concrete casting.

Conference paper:

2016: “Liquid State and Concrete Uncertainties” (Peer-reviewed paper) Ottevaere O., in Risk Panel, International Research Based Education 2016, in celebration of the 175th Anniversary of the Bartlett School of Architecture, University College London (UCL) and in collaboration with the Association of Architectural Educators (AAE) and the Architectural Review (AR), London, England (

Conference paper upcoming:

2016: Ruled based constructions or the materialization of a line in motion(Peer-reviewed paper), Ottevaere O., in the “Design Strategies: Situated Creative Machines,” session, CROSS-AMERICAS: PROBING DISGLOBAL NETWORKS, Association of Collegiate Schools of Architecture (ACSA) Annual Meeting 2016, Santiago, Chile (


2016: “Concrete as Process”, Advanced Technology Lecture Series: Technology and Material, American Institute of Architects (AIA) Hong Kong Chapter.


Intelligent Wave

Project team:
PI: Yan Gao, Assistant Professor, HKU
co-PI: Xin Guo, Assistant Professor, The Shenzhen University
co-PI: Victor Leung, PhD Candidate, MIT

Project funder: Shanghai MoMA


This project investigated a more design-orientated making process while embracing the emerging robotic technologies. Such proposition unfolds into a research project, i.e. the “Intelligent Wave”. The project went through the three stages including the physical experimentation, the computational simulation, and the design & making of a robotic structure in the end. The research process synthesizes abstract geometries, Complex System theory, 3D print, and the automatic control through computational protocols. The core objective of the Intelligent Wave project is to achieve a kinetic structure with simple rule-based component system that generates complex surface behavior. The breakthrough of this robotic structure is that, the unified cells that are repeatedly connected under the triangulation principles and geometric constrains, are able to generate infinite global reconfigurations of both the spatial structure and the unpredictable geometric pattern. The emerging reconfigurations starts when the equilibrium is broken by external forces, while the whole assembly freezes when the structure finds its new equilibrium after the external force ceases. Such behavior is scripted into digital modelling techniques and animations before the realization of the program-controlled structure. Instead of using dynamic pistons, the transformation is achieved through the sequential local sliding and rotation which trigger the global surface transformation into either concave or convex. The ongoing article compares the above research project with the typical robotic architecture and categorizes the concurrent experiments of robotic applications in architectural research. This research project embraces the design intelligence for a more holistic perspective in multiple dimensions, in order to explore the design opportunities while expanding architects’ territories.

Anticipated outcomes and outputs:

A conference paper that will lead to a journal paper

Exhibition in Robotic Future, 10th Shanghai International Biennale