How to make oxygen draining system in a custom dimension [TUTORIAL] (with minecraft air)

Almost no one made tutorials about oxygen systems in custom dimensions, so here’s a mini tutorial! (MCreator 2025.2)

1. Create a new procedure.
2. Set the trigger to On player tick update.
3. Add an if-else block:
  - If the player is in your custom dimension:
      - Pause for 1 second (server-side)
      - Reduce the player's oxygen by 5.
  - Else:
      - Set the player's oxygen back to 300.

Hope you liked the mini tutorial!