"Some of the ideas were quite crazy,"says visual effects producer Jason Bath."Did they turn up in the middle of the desert,are they on an alien planet,are they staring out at nebulas? There was a big journey about what this space would look like before we started manufacturing it,which is why you need to start a year out."

For Luma Pictures,the complexity lay in pulling together disparate elements – real-world street footage shot alongside the train line;repositioning of the camera angle within a 360-degree filmed environment;action sequences shot atop a stationary train on a studio backlot (with Larson doing many of her own stunts);and face replacement for the actors where stunt doubles were used,or digital doubles where the stunt was too dangerous to be performed in real life.

"We pretty much do face replacement on every Marvel film,"says Brendan Seals,Luma's visual effects supervisor on the film."It's no longer enough to have someone who lookskind of like the actor – it actually has tobe them. Otherwise you have people pausing on a frame on YouTube and saying,'Hey,that's not Brie'."

Working on these big-budget blockbusters is an increasingly important part of the Australian visual effects industry. In 2017-18,Screen Australia reports,41 foreign projects spent $104 million on PDV (post-production,digital and visual effects) in Australia.

In the early days,Rising Sun's Ian Cope remembers,being at the other end of the world from Los Angeles didn't make life easy."When we started,it was'where's Adelaide?',"he recalls."I used to have to write things out to a data tape,which would then be FedExed to a client – it would take a couple of days to get there. Now we're delivering finished shots every day and they get dropped straight into production."

There's no doubting the quality of the work being done in Australia."We have a good reputation with the studios,they like to work here if they can,we always punch above our weight,"says Animal Logic's Jason Bath."But growing the industry bigger than it is is difficult."

That's because the VFX sector is dependent on rebates to attract work,and the studios eagerly chase those rebates around the world.

At 30 per cent,Australia's rebate is generous – but not as generous as the 45 per cent the studios can get in parts of Canada,for example.

South Australia has recently announced an additional state-based 10 per cent rebate,which helped lure the UK-based Mill Studios to town. In Sydney,meanwhile,around 200 people lost their jobs late last year when Method Studios – which absorbed Iloura about six months earlier – closed down (it still has an office in Melbourne,which was responsible for the Emmy Award-winning work onGame of Thrones'Battle of the Bastards episode in season six).

"It's a turbulent industry and you do your best to stay at that optimum level to suit your needs and to service the clients,"says Luma's Brendan Seals."But it has become a bit of a rebate chase globally."