Taival Mechanics #9: NPC Schedules & Simulation
Hey there! One of the most crucial things in designing an open world game is making the world feel like it's alive. It's easy to simply make the game world big, but to make it feel like it lives on it's own, that things happen there without the player causing them with their own actions is the hard part. That's why we're developing two systems: schedules and simulation.
How do schedules work? In Taival, all humanoid NPCs (or otherwise more sentient, I'm pretty sure we don't need the little spiders in that one cavern follow their daily activities) are given schedules. They may consist of walking to the tavern and sitting around at 08:00, heading to the forest for some work at 12:00, taking a walk around the town at 18:00, and heading to their home for a good night's sleep at 21:00. With each NPC following their own schedule instead of just walking around aimlessly all day long, it feels like the town is breathing on it's own. Do you have any ideas for fun or interesting new schedule activities we could add?
In an open world game, things most often tend to stop when the player is not around, with NPCs being despawned until player happens to return again. While this is perfectly understandable for performance reasons, we decided to take a new approach here, that's the simulation part! Using DOTS and Burst (magic complicated tech that exists in Unity game engine) we are able to make the NPCs still move and exist according to their schedule everywhere in the game world performantly, even if the player was miles away from them. The NPCs still disappear when the player is far enough, but behind the scenes their position and schedule still gets updated.
This may be seen to the player by for example when a quest marker points to a quest giver in the map. Instead of it being a static marker and the giver just stands still, the player can see it moving and living, and when arriving there the quest giver is spawned exactly where it should be as seen on the map! This system isn't limited to humanoids either, as animals and similar may also wander around, even if they didn't have a schedule. Below you can see an example of a few NPCs moving around the town, with the player being nowhere near it:
Of course, the player (probably) wouldn't see all NPCs around the world on their map all the time, but this opens up a lot of fun possibilities. Want to hunt a certain type of animal, or gain it's shapeshift form? Equip a tracking talisman and see all nearby animals live moving on the map and on your compass. Any other uses you can come up with? Let us know in the comments!
These two systems together allow for some immersive things to happen. As the NPCs follow their schedule and move through the simulation on their own, the player may be walking through a forest or following a road, and may encounter NPCs (or enemies!) that have moved there on their own. This makes the world a lot less predictable and more dynamic at the same time.