SINGAPORE - Experts weighing in on the comments by Qatar Airways chief Akbar Al Baker say that while parts of Jewel Changi Airport may bear some resemblance to elements of a new airport facility planned for Qatar's Hamad International Airport in Doha, it does not mean they are copies.

They say the design elements have been around for some time, and have been applied around the world.

For example, Jewel's geometric-grid shell structure - which utilises diagonally intersecting metal structures and glass to allow in natural sunlight - is not new, nor is it unique to Jewel, said veteran urban planner Steven Choo.

Dr Choo, who is the chairman of real estate advisory firm VestAsia Group, said the same design can be seen at the British Museum in London.

Other experts pointed out that the western concourse of King's Cross Station in London, as well as the Smithsonian Institution's courtyard in Washington DC, also utilise similar technology for their roofs, referred to in the trade as diagrid.

The Straits Times had reached out to architects as well as academics teaching design and architecture for their perspective on comments made by the Qatar Airways chief who, two weeks ago, said Jewel copied the design for a Doha airport extension.

It sparked a heated discussion on who copied whose design, with Changi Airport Group and world-renowned architect Moshe Safdie, who designed Jewel, firing back by saying that Singapore did not copy the idea or design for the Jewel project.

Mr Al Baker made the comments in October at the unveiling of expansion plans for Qatar's Hamad International Airport. Digital images posted on the airport's Facebook page show an indoor tropical garden with a water feature design, which looks similar to Jewel's indoor waterfall.

Dr Choo said Jewel's rain vortex, the indoor waterfall, could be viewed as an advancement in technology from the two-storey rain oculus in Marina Bay Sands (MBS), also designed by Israeli-Canadian architect Safdie.

"The idea of letting sunlight and rain water pour into a building is not new; the Romans did it with the Pantheon.

"But it's up to the architects' creativity, along with technological advancement, to express these design elements in a different scale and context," said Dr Choo.

Buildings with seemingly similar designs exist all around the world. Take skybridges for instance, say the experts.

Last month, CapitaLand officially launched a mixed-use development Raffles City Chongqing in China, which has eight towers and a connecting skybridge across four of them. It was also designed by Mr Safdie.

The Linear, a condominium along Upper Bukit Timah Road, also has a long overhanging roof. Designed by Japanese architect Kenzo Tange, the condominium was completed in 2006.

MBS, which has an overhanging Skypark, was completed in 2011.

Dr Choo said the designs were implemented differently.

"The condo's architect cleverly worked with the site constraints, which is a long plot of land, and gave it a long and interesting roofscape. The one at MBS may look similar but it's curved. The height and scale of it also makes it different," said Dr Choo.

Another design that has seen different iterations is the "elongated egg" shape, seen in The Gherkin in London, Torre Glories in Barcelona and Pearl Bangkok in Thailand.

Images of buildings widely shared on social media may have made it harder for architects and their quest for an original or innovative form.

Dr Jeffrey Chan, assistant professor at Singapore University of Technology and Design's (SUTD) Humanities, Arts and Social Sciences faculty, said the "instagrammable architectural images" culture has led to an "unintentional proliferation of architectural imagery, like a strong visual meme, which can sway architects when they design".

Dr Chan, who specialises in design theory, added that architects may also face pressure from clients to take inspiration or design elements from existing buildings.

"To use a tested design, but improve on it marginally, is a risk-averse strategy when the return on investment is critical. However, this does not mean that the architect must be passive.

"Instead, they should strategically consider the client's interest and advise on the best course of design action," he said.

At the unveiling of expansion plans for the airport in Doha, Mr Al Baker said their designs were "already on the table nearly six years ago". Mr Safdie responded saying that he has never been to Qatar nor has his architecture firm Safdie Architects ever done any work in Qatar.

Architects may also be influenced by current design trends, such as incorporating nature and greenery into buildings.

Mr Tan Kok Hiang, founding director of Forum Architects and Professor in Practice at the National University of Singapore (NUS) School of Architecture said: "With the idea of greening becoming more popular, I think we'll see more of giant glass roofs hovering over landscapes incorporated into buildings.

"At the end of the day, the public benefits, so we should not make a big deal of which designs are original."

But he added that architecture should not be judged by how it looks.

Mr Tan said: "How (the building) is supported, how it functions in relation to users and how it relates to the context are just as important. With looks alone, subtle differences can often be indiscernible to the layperson."

While a direct copy is a big no-no, adapting a design or a technology and applying it in a unique manner is not frowned upon in the industry.

Mr Donald Conning, managing director of global architecture and design firm Gensler Singapore and Bangkok said: "A common solution - perhaps an efficient and cost-effective technology - can often be adopted across projects.

"The introduction of a new twist, unique approach or advancement in technology to achieve a greater span is acceptable in the design community."

Professor Erwin Viray, head of the architecture and sustainable design pillar at SUTD, said that successful design features may be adapted and improved upon by others.

"It's through careful thought and hard work that certain things come into place. Sometimes, when (a feature) is successful, people tend to test how they can make it better by starting with what's already in place."

But there are rules in place to prevent wholesale copying of designs.

Architects registered with the Board of Architects Singapore have to adhere to the Architects Act that governs architects' professional conducts and ethics.

Architectural designs are also subjected to copyright laws. Developers are typically granted a licence by the designer for the use of the project duration and life cycle.

Prof Viray said: "Creating a work of design, a work of architecture is very demanding. As German architect Ludwig Mies van der Rohe once said, 'One doesn't invent a new architecture every Monday morning.'"