there's this DigiPen game called "TAG: The Power of Paint" and it has an extensive object system.
this page will show you some information about how it works.
in TAG, unlike most games and game engines, objects are defined by .xml files and are not hardcoded into the game itself. this is why you can, for example, add deprecated objects back into the game without ever touching the game code. for a regular player, this is just some random fact, but for modders, this is a game-changer as they can add in their own objects. sadly, we can't add any code to such objects, but this is still great for modders.
objects are component-based. for example, an object uses a MeshComponent and an StdPositionComponent or RelativePositionComponent to be visible as a 3D model in-game.
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