Subnautica is an open-world survival-exploration game set in an alien ocean. The game was originally to be set in space, but Charlie Cleveland, cofounder and design director, was a scuba enthusiast and suggested an undersea world would be a strong visual differentiator for an engaging game. The game places you on a hostile ocean planet where your worst fears – like the chilling sense of an apex predator lurking just out of sight – are real. 

Players can swim in any direction at any time and there’s something interesting in nooks and crannies in almost every direction.

In 2015, Unknown Worlds transitioned from an in-house engine they used for their previous game, Natural Selection 2 to Unity. “When we started working on Subnautica we knew we needed to try different gameplay ideas,” says McGuire. However, the proprietary engine wasn’t as effective for rapid prototyping, so they used Unity and loved the speed with which they could create. “We gradually transitioned from prototyping mode into development with Unity. It was especially valuable because we could easily integrate our custom tools and extend Unity to build out our content.” 

While graphically complex games are often unique, there can be unique issues when porting them to new platforms. And in the case of downporting Subnautica to Switch, the studio faced a platform with vastly different capabilities and requirements than a PC or console.

Some challenges of producing one game for many hardware platforms include game controls that range from a few finger touchpoints to multiple joysticks, and CPUs that range from older chips to 24-thread, 4.8 GHz hyperthreaded processors for desktops. Thorough QA can require testing potentially hundreds of devices, which can be quite time-consuming to meet some not-so-obvious certification requirements. 

Porting a game like Subnautica – with its custom water rendering and impressive voxel environments – from PC to console was one thing. Porting it to Switch was completely different: it would not be simple and might not even be possible without stripping out some of the game’s best features.

The studio has worked with Unity on a number of initiatives since 2013 – including with Unity Integrated Success – and Unity was the core component of the game, so reaching out to Accelerate Solutions for custom development assistance was a logical step.

The Unity team studied the studio’s early work and prototypes, asked key questions, and started building a comprehensive plan for the port. Verrette says, “The Unity plan tackled optimization, how to move everything over, and also pointed out where the big challenges were likely to be.” There were a lot of unknowns because the game was originally built for PCs, not consoles, let alone Switch. “We knew we’d have to make adaptations along the way, and Unity’s flexibility helped us all keep an open mind and go after the best solutions possible.”

Making sure artists are always accessing and contributing to the right assets and build versions is a common challenge. UW had experimented with several source-control products before Plastic SCM, the one-stop solution for handling all their code and art content. UW stores the entire Unity Editor inside their repository to ensure contributors are using the same version, whether it’s a coder in San Francisco or an artist in Brussels. Verrette explains, “Our repository is massive, but everything is always in sync. And Plastic SCM is remarkably user friendly – our artists and non-technical contributors aren’t at all intimidated by it.”

One of the most important issues the Professional Services and UW teams had to solve was memory management.They considered implementing the Unity Addressable Asset System, a method to load assets that simplifies content pack creation and deployment. However, the Subnautica architecture was unique and not exactly what the tool was designed for. Switch memory is comparatively limited for any game, especially one of Subnautica’s complexity.

In collaboration with the Unity engineers who had developed the Addressables system, the teams managed to adapt the tool for Subnautica. It was easy for the studio to get additional assistance from Unity as they prepared their games for next-gen devices. “Unity knows our game, they already understand how our systems work, and they’re sharing everything they know about next-gen roadmaps with us,” says McGuire.

After the initial rave reviews for Subnautica: Below Zero in Early Access, Unknown Worlds continued to use Unity to optimize virtually every element of the game. Its early 2021 release – across PCs, consoles, and Switch – promises outstanding commercial success and an exciting future. According to Verrette, “Unity not only brought out our best gameplay, they also helped make this amazing game available to a new Switch audience. They’re more than a long-term partner – they’re part of the core team.”