Game Mechanic: Rooms and Doors

About one and a half years ago, I came up with this mechanic for space traversal. After 17 months, I decided to turn it into a short blog post in case someone would find a good use for it, whether it's me or someone else. It's not a perfect system or a mechanic even, just a rough idea I had back then.

A room is a small region in the world encompassed by the doors. A door is a border between two neighboring rooms. Each door has a size. A character (NPC or player's) has a speed and size. An object has a size. The speed of a character defines how many doors it can pass through in one turn. The size of a character or object defines the size of doors it can interact with in various ways.

The default size for a character is 0. In a game about humans, a human's size is 0. In a game about giants, a giant's size is 0. A character with a greater size is physically larger than a character with a lesser size. If a character carries an object of a size greater than its own, its size is considered greater for the purposes of dealing with the doors.

Let the size of a character or object be C, and let the door's size be D.

• If C ≤ D, a character or an object can move through the door.
• If C ≤ D - 1, a character or an object can squeeze through the door.
• If C ≤ D - 2, a character can interact through the door (attack, use objects, etc.).
• If C ≤ D - 3, a character can perceive through the door.
• If D = ∞, the door is a wall.
• If D = -∞, the door is an open space.

This system could be applied in systems that are not about traversing a physical environment, but I do not have good examples at the moment.