Why Horizon Forbidden West: Burning Shores’ Embrace Is A Secret Tech Marvel

When Guerilla Games released a trailer for Horizon Forbidden West’s new expansion, Burning Shores, the other studio’s developers may not have been paying attention. I noticed it instantly.

The 0:45 hug is a technical flex like YOU HAVE NO IDEA. https://t.co/h0dmivkOpl

— Zalavier Nelson Jr. (@WritNelson) April 19, 2023

“The 0:45 hug is a technical flex like YOU HAVE NO IDEA,” writes Strange Scaffold head Xalavier Nelson Jr. As such, in the game he is rarely seen by two characters hugging each other. For developers, this is very difficult to achieve while still appearing sane and trustworthy. Still, Guerrilla has given Aloy a warm hug to her friends since Zero Dawn.

So how does Guerrilla achieve this technological feat? We spoke to Richard Oud, director of animation at Guerrilla Studios. It’s just that we’ve grown accustomed to the extreme challenges it takes to bring hugs to life…and we’ve recently made some technological strides in the field of video game hugs.

WARNING: The text of this article does not contain spoilers, but the video content in this article contains cutscenes from the endings of Horizon: Forbidden West and the Burning Shores DLC. Please view at your own risk.

hug resolution

Guerrilla and other developer challenges start with motion capture [mocap] A suit that records standard movements and facial expressions in the game industry. The motion capture suit works through sensors scattered throughout, which software can track and translate into recorded movements. But when the two actors in his motion capture suit hug each other, the two bodies are pressed against each other and so are the sensors. This completely hides half of each person’s sensors from the software’s view.

This means that a human must manually “solve” the captured motion data, Oud explains. That means the software has to know where the sensor should be at all times. In this case, they must resolve all missing sensors for the duration of the hug. According to Oud, this is a time-consuming task that machine learning may actually speed up in the future, but for now it has to be done manually in-house or outsourced to another studio. there is. The animator cannot touch the scene until this is done.

Once that is resolved, we have a second problem. Motion His capture suit is basically nothing more than a flashy second-his skin, but the hugging character in the game usually wears it.

“For example, if you look at things like the armor that Aloy is using … all that stuff is not considered in motion capture,” he says. “So even if you have the data that you have solved, you only have the base. So you have to go there and start addressing everything towards the fact that someone is actually reaching around the armor for example. So you have to deal with the whole animation from that point onwards and make sure it doesn’t intersect with the cloth the person is hugging.”

If you’ve played a Horizon game, you can imagine that this is no easy task. Aloy and her friends all wear elaborate and detailed costumes, often with many embellishments and other elements sticking out.

capillary physics problem

After that, the problems never stop. Typically, as Oud mentioned, Horizon’s motion capture actors wear head mounts to track facial expressions and provide animators with data to work with. But since he can’t wear a giant head mount while hugging, the animators have to manually animate all of the character’s facial expressions, according to Oud, for his three different endings in Burning Shores. are all fully keyframe animated for this reason.

More problems arise when animators dabble in scenes. One of the problems, according to Oud, is that scenes with hugs actually require the animation to run at a higher frame rate.

“You want to really feel the connection between people. ,” says Oud. “[T]The engine actually interpolates between frames. Usually, I actually animate at 30 frames per second, but I’m running the game at 60 or 120 frames per second. In this case the missing frames are usually just calculated by the PlayStation.

“And if the refresh rate is too low, it can actually start to shake, for example. So the compression for these types of animations needs to be really super precise so there’s no jitter and basically at the maximum power the machine can handle at the time will be played.”

Finally, the room has a gorgeous, flowing red elephant, Aloy’s hair.

According to Oud, in Horizon: Zero Dawn and Forbidden West, Guerrilla basically has eight different hair “poses” in order for the team to accommodate most of Aloy’s movement and movement speed. I was using a hair setup. Her hair is made up of many “collision capsules”, which for non-animators can be imagined as a mass of tubes that are attracted to her in one of the poses it is set in and then released once the pose is complete. I can. Natural hair with movement.

But for Burning Shores, her hair got some upgrade. The team wanted to grow her Aloy’s hair out further, but the idea to do so only came near the end of the project when the majority of the gameplay was complete. However, since cinematics usually happen towards the end of a project, we were able to implement Aloy’s new hair features in cutscenes like Seika and Aloy’s hug.

“The way Zero Dawn and Forbidden West worked was that clash. Hair clashes were locked, right?” Oud explains. “There wasn’t really a way to override it unless you changed the costume so that it didn’t actually intersect with her armor by having her hair posed in a new pose.”

To solve this problem, Guerrilla introduced what Oud called “movable colliders”. Oud explained to me: If Aloy’s hair is made up of bundles of small tubes, there is a law of physics that makes them bounce off each other when they come in contact with another tube. But they cannot move by themselves. So the team introduced new collision capsules that react specifically to them, but are only available in cinematics, wrapped around Seika’s arm. The result was a hug in which the hair seemed to move naturally as the arm passed through it, rather than awkwardly sitting on top of it or being weirdly cropped.

“In this case, when Seyka reaches into her hair and starts walking through it, we actually animate a capsule that looks like a moving collider,” he says. “We actually animate at the same speed and same position as the arm is actually moving. This reacts to the hair and moves her arm away from the hair to make room for the arm to hug.” Looks like it’s going to work. Hopefully it’s as easy as I can tell.”

This change is made possible thanks to Jolt Physics, the open-source physics engine that Guerrilla switched to for Forbidden West. Among many other benefits, you can have more objects with real physics in a given scene, such as allowing a lot of Aloy’s hair.

“Static worlds are great, but when things really start moving, they actually have AI and they react to physical objects, the more it does, the more computer applications in this case do. More calculations need to be done, less calculations need to be done, basically at a given point in time,” says Oud. “That’s also one of the reasons why we actually chose only his PS5 in this case. It’s possible to have much more visual fidelity and more objects on the screen than we were able to achieve with the PS4. I made it.”

engineering intimacy

Issues like the one Oud describes affect every kind of intimate interaction characters have, not just hugs. This is one reason why many games don’t often show the simple act of one character passing an object to another. Detaching a 3D object from one character and attaching it to another requires rules, physics, and animation. It looks smooth and natural, but it’s a “technical nightmare,” says Oud.

Kisses run into similar problems to this and hugs, or basically when two characters need to touch and then move in tandem in a way that normal people do. It’s cheaper from an economic, technical, and time standpoint to not do it, or to hide camera tricks and such interactions behind off-screen when passing items.

“But we’re a little more ambitious at times. You know what I mean? It’s about how far we can do one thing and push those boundaries, or how far the characters can really go with each other.” It’s time to see how much you can interact with, which is probably also why you hugged Aloy so much.

Both Oud and I recall a similar discussion that occurred in the gaming community over a year ago. The developer surprised many by explaining how difficult it was to do something as simple as successfully opening and closing a door. Wood said that things like hugs and doors are not only generally difficult to animate, but also allow the player to pause the game, move the camera, or do other things while the activity is taking place. He points out that it becomes even more difficult in a game space where you need to be able to do things. place. “If you don’t fix it, people won’t believe it and won’t accept it.”

But guerrillas have found that such interactions, especially intimate interactions such as hugging, are important to the kind of human stories they want to tell. Some people hug often. It would feel strange that a character in the studio wouldn’t be allowed to do that. I’m happy to hear that you’ve noticed that the exchange is going well and that you’re calling out to me. But he adds that the success is that the player doesn’t notice them at all.

“Just getting out of a hug or an intimate moment doesn’t tell the story,” says Oud. “So we have to find a way to actually do these things, but still make sure that the feeling and the connection are delivered to the player and the player doesn’t have to think about it. [the players] If we feel it, we are already blessed to have actually achieved our goals. “

Rebekah Valentine is a news reporter for IGN. you can find her on her twitter @duck valentine.