His creation, the BioShell - a lightweight but tough translucent plastic sheet for building small shelters - is something that even Mother Earth would love.
The plastic, made of polylactic acid or its composites, is waterproof and resistant to strong winds and typhoons - yet completely biodegradable. This means it can be decomposed by micro-organisms in 90 days, at a temperature of 60 degrees Celsius.
Each BioShell shelter is created from bolting together several, interlocking, saddle-shaped BioShell units. Daylight is able to pass through the sheets.
The plastic sheets are only 1.5mm thick, so they are lightweight, easy to assemble, dismantle, transport and store - thus saving on energy consumption.
Each BioShell shelter - formed of three sides and a roof - measures 2.4m high, 2.8m wide and 2.8m deep and weighs only 60kg. Okuda's original geometrical BioShell design is awaiting an international patent.
"The BioShell is ideal for exhibition booths and disaster-relief shelters, both of which will need to be put together and taken away quickly," says Okuda, 43, who was born in Osaka and teaches at the National University of Singapore. He is also a consultant with Singaporean architects, State of Architecture.
The first-class certified architect, who graduated from the Kyoto Institute of Technology in 1995, also worked in Switzerland.
He first became interested in exploring environmental architecture when working in Hong Kong, from 2005 to 2008. "I loved spending time on the beautiful islands, like Tung Ping Chau. But I was sad to see so many plastic bags along the coast," he says.
"Another time, I attended an exhibition, and I saw how it produced mountains of waste. I began to think of ways to reduce waste disposal [for my projects]."
Okuda applied the same kind of thinking for disaster-relief shelters. "The shelters can be an obstacle for redevelopment because they can't be taken away or stored easily and will eventually become waste," he says.
It took him four years to come up with the BioShell. After all that work, he finally made a sturdy structure from the thinnest, lightest material he could find. This year, the BioShell is ready for commercial use. A few companies have already approached him seeking partnerships.
Okuda is specifically interested in using ordinary materials in innovative ways. It's an idea that came from his earlier involvement in a Paper Church project. The temporary church in Japan was made for survivors of a massive earthquake in Kobe in 1995. The project was led by well-known architect Shigeru Ban, and Okuda was a graduate student at the time.
He says: "It was an eye-opening experience. I was inspired by how Shigeru Ban used paper - such a weak form of material - to construct a real-size building."
As for his own work, he will continue to follow four principles: innovation, simplicity, elegance and sustainability.
"Sustainability is a basic standard for buildings nowadays," he says. "I am more interested in using sustainable material to build new types of aesthetic architecture for the future."
The BioShell is on display at the Hong Kong and Shenzhen Bi-City Biennale at Kowloon Park until April 23