Chris Hopewell heard the sound of the first plane collide with the World Trade Centre on September 11, 2001, but it was his cats running in circles that tipped him off that something disastrous had happened.

After the Australian artist opened his curtains and went onto the balcony of his Williamsburg apartment, he saw the damage that had been done to the tower, but had no idea what had caused it.

At his wife's urging, he set his video camera on a tripod, framed it up and started rolling, expecting to film the flames being extinguished and nothing more.

What he captured is now one of the most well-known videos of the horrific events of that New York autumn morning.

"The second plane came in and that was captured and that was horrific," he said.

Chris Hopewell had a clear view across the East River to Manhattan from his apartment in Brooklyn. ( Supplied: Chris Hopewell )

Hopewell kept his camera running for six hours, and ultimately captured both towers collapsing.

But it was the vision of United Airlines Flight 175 crashing into the South Tower that was played around the globe again and again over the coming weeks and months as the world took in the significance of what had happened.

If you listen to the original recording from the day, you can hear the horror in the voices of people gathered on the balcony taking in what they are seeing.

As the second plane hits, a woman can be heard crying out: "Oh my God. They did this on purpose."

Sixteen years later, Hopewell believes he is still processing what he saw that day.

"It's very hard to describe because it's like falling off a building or something. Your stomach gives way," he said.

Although he avoids making a connection between his art and 9/11, it was Hopewell's art that took him to New York and led to his being in a location on that morning that allowed him to record the historic moment.

Hopewell had moved to the US in 1987 as a budding artist fascinated with the early abstract expressionism movement that had sprung up in New York after World War II.

When he first arrived, he lived in a squat while getting started in the film industry as a production designer and art director, then saw an opportunity to convert a derelict building into studios for artists.

"That's the building that was across from the Twin Towers where we saw it all," he said.

Chris Hopewell is now based in Fremantle, WA but recently exhibited at the Sydney Contemporary art fair. ( Supplied: Chris Hopewell )

Hopewell is now based in Fremantle in Western Australia. His paintings continue to be inspired by his time in New York.

A series of paintings he recently exhibited at the Sydney Contemporary art fair show his fascination with layered, abstract textures that hark back to the graffitied billboards he would see in the subways.

"I ended up ripping off a lot of the billboard posters and taking them home and applying them to my painting and working over the top of those," he said.

Once more he is part of a large group of artists, but whereas developing the art studios in New York was a financial move, this time his involvement is motivated by wanting to support his local creative community.

Art Collective WA was born when the Perth art market started to decline and several prominent galleries closed down around 2012 and 2013, leaving a number of artists without a home for their work.

Hopewell says the not-for-profit group has turned out to be a successful model that has help artists survive a slump in the market.

He does not think the attack directly influenced his art, but says that what he witnessed that day has stayed with him ever since.

"Subconsciously a lot of things were brought into question, I guess, like your mortality, how fragile anything can be," he said.