Ergonomics

In the real world, architects design for the human body. In your game world, you are designing for the "Avatar." You need to know your avatar's metrics: How high can they jump? How wide is their collision capsule? If you design a door that looks real but is too small for the game camera to fit through, your design has failed. You must calculate standard heights for steps, railings, and ceilings that work for your specific game engine.

You also need to consider "Cognitive Ergonomics"—how easy is it for the player to understand your space? Your design should subconsciously guide the player. Use lighting to highlight the path forward and architecture to frame important landmarks. If a player gets lost in your building, it's not their fault; it's a failure of your spatial design.