Stranger Things has dominated the pop culture sphere this summer as the series made its triumphant return to Netflix after a three-year hiatus between Seasons 3 and 4. The epic fourth season took the show to new heights with longer episodes, more intense horror sequences, and absolutely incredible visual effects as we began to truly dig into the origins of the Upside Down and its apparent master. While Season 4 is wholly impressive, there's one moment that has been on everyone's mind since Volume 1 dropped at the end of May: Max's "Running Up That Hill" sequence.

In an interview with Collider's Samantha Coley, Visual Effects Supervisor Julien Hery broke down how his team at Rodeo FX expanded Vecna's mind lair and built a ton of the scene's visual effects around Sadie Sink's remarkable performance. The scene is essentially broken down into two parts: the first half in which Vecna (Jamie Campbell Bower) has Max (Sink) restrained, intent on adding her to his collection of wayward teens, and the second where she wounds him and runs back to the safety of her friends. "There are shots where you have Max on the island and Vecna, and then when it changes, and when it's on the island, it's basically the whole island is made practical," said Hery. "And then when she manages to escape, then it's basically a set of a full-on blue screen set. So, everything is a blue screen."

The VFX teams behind Stranger Things are tasked with creating both massive landscapes that fill the entire screen, as well as tiny intimate details in close-up shots. And in this scene in particular a lot of their work is dependent on the performance of the actors in the scene. Hery had high praise for Sink's performance in both portions of the scene as he explained how they created the twisting vines that Vecna uses to trap her in his lair:

"It's fairly impressive. It's all CG vines. There was no placeholder. I think there were maybe a couple of shots where she had a placeholder on the wrist to help her act the way she was [restrained.] Otherwise, she didn't have any ropes on her neck or anything like that. So, I think the performance was really awesome. What we did on those was match-moving her performance, making sure we had everything aligning to her perfectly. So, then we could animate all those vines onto her neck and make sure it's sticking onto her performance, but we were really relying on what she was doing. Every time she was feeling like suffering or suffocating, we added the vines to animate differently, to contract, to curl, just to make sure it was matching really what she was doing on the day."

stranger things season 4 sadie sink
Image via Netflix

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In the sequence where Max runs out of Vecna's lair, the monstrous villain tries to stop her by crushing her with the debris within the Upside Down. With the majority of this scene being CG animated, the VFX team had to create effects that both affect and react to Sink's acting choices and movements through the sequence. Hery explained the collaborative process saying, "So, we had obviously an edit of the sequence, where it would be. So, we had cues from the actress' performance giving us an idea, "Okay. We need to have debris on the right, on the left," and know a bit of timing." He continued, "We start doing what we call a previs, a previous visualization. It's basically a mock-up of timing. So we had fairly rough rocks just falling down, just to get an idea of how does it blend? Does it create fear? Does it give the proper feeling of claustrophobia that you can feel being chased like that?"

Explaining how all of those moving pieces come together Hery said:

"We did like what we call a body match move. So, we did a match move of performance. So, we have her running digital that way. When we run simulations of things exploding, they can collide, and pieces can collide on her body. Then, when she's running or so, we can have the blood that we create in CG. The blood can collide on her, and even the smoke that we added on the ground can collide with her footstep. We still keep her performance, but we have a, let's say, a digital double that we only use to recreate those interactions that otherwise you won't have. So, everything is interconnected very much with the performance of the actress that way."

Stranger Things Season 4 is now available on Netflix and be sure to stay tuned at Collider for our full interview with Hery. In the meantime, check out our Season 4 interview with the Duffer Brothers down below.

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