The Making of a Button-Door Mechanic in Unreal Engine 5

In this project, I tackled the creation of a button-door interaction system in Unreal Engine 5, building on the foundation of the First-Person template. The primary goal was to develop a functional system where a button press could open and close a door, complete with animations, sound effects, and visual indicators such as lights to show the door's status.

The Design Process

Initial Setup and Blockout

Before diving into the mechanics, I began by blocking out the scene with placeholder block meshes. This step ensured that the layout of the door, button, and surrounding environment felt intuitive and realistic before adding the detailed assets and blueprints.

Blueprint Separation

To keep the system modular, I created separate blueprints for the door and button:

BP_Door_Buttoned_Door: This blueprint manages the door's state and movement. It includes a timeline for smooth opening and closing, boolean variables for tracking states, and sound effects for user feedback.

BP_Door_Buttoned_Button: This blueprint interacts with the door, triggering its functionality through a line trace from the player.

Key Features

Button Interaction: The player uses a custom input action mapped to the "Interact" key. When the button is pressed, a line trace detects the button and calls its ActivateButton event to trigger the door's movement.

Door Animation: A timeline in the door blueprint animates the door's rotation, providing a smooth and responsive opening/closing effect.

Visual Indicators: Lights on the button change color to reflect the door's state: green when the door is open and red when closed.

Sound Effects: Unique sounds play when the button is pressed and when the door moves, enhancing user feedback and immersion.

Challenges and Solutions

Issue: The button would sometimes require multiple presses to trigger the door.

Solution: I added boolean variables like Is Button Moving and Is Door Moving to ensure that interactions couldn't overlap, avoiding conflicts.

Issue: Door sounds would stack, playing multiple times.

Solution: A check using the Is the Door Making Noise boolean prevented multiple sound instances from playing simultaneously.

Issue: Incorrect button-to-door assignment during testing.

Solution: I ensured the proper door was assigned in the button's details panel and made this step explicit in the instructions.

Lessons Learned

This project reinforced the importance of planning and modular design in game mechanics. Breaking functionality into smaller, self-contained blueprints made debugging and iteration much easier. Additionally, testing early and often helped catch edge cases that could have been overlooked in a larger system.

Next Steps

Looking forward, I plan to expand this system with more complex features:

Multiple buttons controlling a single door.
Timed doors that close automatically after a delay.
Different door type animations and triggers.

This process demonstrates the power of Unreal Engine 5's Blueprint system and the importance of iteration in game design. I'm excited to see where these skills take me in future projects.