By Milaniya Nguyen, Year 12
Rain World is considered to have one of the most complex and organic feeling in-game ecosystems thanks to its unique use of AI and animation. Rain World is a pixelated, survival, platform game released in 2017. Making your way as a small slug like creature, the game allows you to explore a uniquely created environment and eventually learn to survive in it. Now what makes this game’s world feel truly alive is its incredibly intricate and detailed approach to simulating a virtual ecosystem with procedural animation and AI interactions.
One of the main features that makes the game’s movement so organic and realistic is the developers’ use of procedural animation. Usually the movement of players is animated frame by frame. When players assume control of one the playable characters, the movement of this character is defined by a set animation that occurs in response to certain controls and commands being activated. The player will move in a predetermined way as confined by these premade animations. In contrast, Rain World does not use handmade animations for every action, instead, animation is dictated by code. The game’s code responds to commands by creating movement in a context-specific way, instead of just displaying a set of fixed animations.
This animation style makes creatures’ motions happen organically in the ecosystem and generally much more spontaneously. As a result, giving a more immersive feel to the game with the unpredictability of its movement. Animation is determined in real time, directly in response to interactions with the game’s environment.
A key example of this is seen in one of the game’s most common enemies: the lizards. These creatures have AI coded specifically to them that determine their respective abilities and behaviors. As most other creatures in the game, they have individual personalities that dictate how they interact with each other, the player’s character, and the surrounding environment. The lizard’s reaction to others is dependent on their different behavioral attributes. There are 9 types of lizards in total, all with distinctive characteristics.
Take for instance, the yellow lizards. Their AI allows them to work together to cut off or surround the player’s character when hunting it down. Another type are the white lizards who can camouflage themselves in the pixels behind them in their environment. White lizards have a more patient approach to hunting and will usually stay still until the player’s character is in a close enough proximity for the lizards to attack. This creates incredibly unpredictable movement patterns for the characters of Rain World. The intricate attention to detail in creating every one of these creatures that inhabit the game’s world, all contribute to creating the living feel to the ecosystem.
Rain World achieves its impressive AI by coding simple behaviors into the characters, which then lead to more complex actions as these characters interact with each other. The AI behind the ecosystems’ creatures is always active, even if it’s not on screen. When entering a new area to explore, certain interactions, such as fights, may already be occurring. Something is always happening in Rain World’s environment, even if you can’t see it. Similarly to how a real ecosystem would operate, the game’s events are completely unscripted.
Another feature of Rain World’s ecosystem is that every creature in the game has the simple ability to make mistakes. Their actions and movement aren’t perfect, or executed in the most efficient way. They are intentionally coded this way so as to not be completely perfect. This makes the game ever so slightly more realistic as even the non player’s characters are not consistent, not without fault.
In short, Rain World has an incredibly detailed, intricate system that creates one of the most unique ecosystems one can experience in a simple indie exploration and survival game. With the use of AI and animation that create Rain World’s distinctive character movement, the ecosystem of this game’s world is made to feel truly organic and alive.
