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November 2021   |   Volume 23 No. 1

Simple Materials, Complex Outcomes

LEAD’s award-winning YEZO cabin in Hokkaido, Japan is environmentally low impact and was developed using an evolutionary algorithm.
(Courtesy of LEAD)
The Faculty of Architecture’s new Building Simplexity Laboratory has been created based on the philosophy that simplicity in construction can still facilitate spatially complex systems, and in this age of post-digital architecture, simple algorithmic design procedures can lead to complex geometrical built forms.

“This philosophy allows for interesting research in multiple areas including bamboo, engineered wood, Augmented Reality (AR), and many more,” said the Laboratory’s creator Dr Kristof Crolla, Associate Professor in the Departments of Architecture and Civil Engineering and head of the architecture practice Laboratory for Explorative Architecture and Design (LEAD), who has long been an advocate of bamboo as a versatile, and often underrated, construction material.

“Bamboo is spectacular, unique, cheap, pliable and sustainable. Traditionally it is used in construction extensively in places it grows, but not in so-called developed countries,” he said. “There is a great tradition of bamboo craftsmanship in Hong Kong, but usually for temporary structures such as Cantonese opera theatres and scaffolding. But, if treated for biotic attack and protected from rain and UV light, bamboo lasts and is suitable for permanent structures.”

LEAD is about to embark on building a bamboo project in Anji, China where Dr Crolla will also be a judge in a bamboo competition that will see seven more student projects built. There are also engagements with Yangon, Myanmar, to push for the construction of bamboo community projects there.

This summer, a course in creating complex bamboo structures enabled students to work using computational design tools employing digital physics-simulation engines. These tools allow users to simulate the bending or load-carrying behaviour of bamboo ahead of time so that designs can respond to it from the conceptual stage onwards. The team are looking into how AR technology can use headsets to instruct holographically on site.


His HoloLab at HKU uses AR-driven holograms to make building non-standard shapes easy, for example with bamboo. In March, Dr Crolla chaired a conference with several workshops, including one on AR for complex bamboo structures. “It enables direct communication between digital design models and on-site construction via holographic visual guides. Feedback systems between both allow for the production of designs in which materials can be used to a greater performance level.”

It pains Dr Crolla that bamboo is not viewed in Hong Kong as a viable material for permanent structures. He also thinks there is a misconception over bamboo’s value, partly because there has been little evolution in the craft. “The craft of scaffolding is vanishing as few youngsters want to get involved in it,” he said.

He has been working with local craftsmen since 2012 when his team co-designed the award-winning Golden Moon construction in Victoria Park, followed up by the ZCB Bamboo Pavilion in 2015. One of the most exciting parts for him has been communicating with the Cantonese craftsmen – they don’t speak each other’s language but digital tools have made it possible for them to create a workflow and drawing notation system that allows them to communicate the design intent on site practically and translate the digital model into a buildable structure.

“Now we’re continuing to hack this design and deliver process further to encourage wider use of bamboo and evolve it for more uses,” said Dr Crolla. “We are also creating a digital design tool manual for the development of bending-active bamboo shell structures, covering design tools and techniques that link to practical on-site construction requirements.”

The Building Simplexity Laboratory is now applying its philosophy to engineered wood too. “It’s cheap but elegant,” he said, “and digital technologies have provided new, practical opportunities for its use.”

A recent project is YEZO, a cabin in Hokkaido, Japan, which has won multiple awards and attracted interest globally. Its gracefully curved glue-laminated rafters and roof make it environmentally low impact but the essence of the project centred on an evolutionary algorithm that allowed the production of many of these varying curved rafters from a single mould, thus reducing financial and labour costs.

Another project involving engineered wood is being set up by Dr Crolla in collaboration with student Gary Fung Ka-chun. His thesis project, ‘Simple Assemblage’, offers a solution for renovating/ repurposing Hong Kong’s many abandoned buildings in rural areas. It comprises an innovative timber building system that provides economically and ecologically sustainable architectural solutions using the latest digitech to design and manufacture elegant and durable wooden structures with low-tech construction systems suitable for easy local assembly.

“What is great about this is its flexibility and how the system is overhauling the usual ‘design-bid-build’ architecture construction format,” said Dr Crolla. “The project’s design uses low-carbon materials like cross-laminated timber and employs geometries at the design stage that will minimise material use during construction and energy consumption when the building is in operation.

“Like bamboo, engineered wood is relatively affordable, hardwearing, sustainable and flexible. The government wants to find economical ways to renovate and repurpose abandoned buildings on Lantau, such as schools and community halls, and ‘Simple Assemblage’ offers a great potential solution.”

Simple Assemblage

Proposal for the conversion of an abandoned school in Yuen Long using the ‘Simple Assemblage’ procedure. (Courtesy of Gary Fung Ka-chun)

Scale model

Scale model of one of the complex bamboo structures from the summer workshops.

There is a great tradition of bamboo craftsmanship in Hong Kong, but usually for temporary structures such as Cantonese opera theatres and scaffolding. But, if treated for biotic attack and protected from rain and UV light, bamboo lasts and is suitable for permanent structures.



Photo credit: Diana Jou