VENICE, Italy — Matt Damon and the cast of Venice Film Festival opener “Downsizing” lavished praise on director Alexander Payne and his producer and co-writer Jim Taylor on Wednesday at the film’s press conference, where Payne said he had consulted with scientists about the human shrinkage aspect of the comedy, which combines sci-fi and social satire.

“Alexander and Jim are so meticulous when they write,” said Damon who noted that when working with Payne, “every shot that he’s making is going to be in the movie, and you can see how he’s going to fit it together like a perfect little puzzle, a Swiss watch.

“Our job is so much easier with a director that’s so sure-handed,” he added, “because you always know where you are; you always know exactly what it is that you need to convey.”

In “Downsizing,” Damon plays a man who agrees to have himself shrunk down in order to live luxuriously in a government resort where he meets a Vietnamese prison escapee played by Hong Chau. Kristen Wiig plays Damon’s wife.

Chau said what she loved most about working with Payne on “Downsizing” is how funny it is. “I hope the humor doesn’t get lost in the bigger story and the heavier issues,” she noted.

The director paid tribute to Italian film industry artistry, praising his Italian production designer Stefania Cella, who works in Italy with Paolo Sorrentino: “She’s a small woman with big hair and big ideas, and she gave me a very large visual canvas to work with: I learned a lot from her.” Payne recounted that in the actual downsizing sequence, “which really allowed her to spread her wings,” the only direction he gave her “was that the downsizing chamber somehow should look like a big microwave oven.”

As for the human shrinkage aspect he did consult with scientists to learn what “would the physics be if you were really that small.” But “we had to decide at what point we would stop caring,” he added. “Really, if you were that small the quality if your voice would change; how you walk would be different. You could survive a fall from a proportionally higher height…You could probably fly a little bit. At a certain point we had to stop caring about that.”