SimpleInputSimulator User Guide

Supported Unreal Engine Versions: 5.2–5.8

Simple Input Simulator is a lightweight input simulation plugin for Unreal Engine. It provides three Blueprint functions to simulate keyboard, mouse, and gamepad inputs programmatically.

The plugin works immediately after enabling. All functions are available in the Simple Input Simulator category in Blueprint.

Parameters:

• Key: UE FKey input key to simulate (Space Bar, Left Mouse Button, Gamepad buttons, etc.)
• Pressed: true for press, false for release
• Player Index: Target player controller (0 = first player)

Parameters:

• Key: Axis input key (Mouse X/Y, Gamepad Left Thumbstick X/Y, etc.)
• Axis Value: 3D vector for input values (typically use X component)
• Player Index: Target player controller (0 = first player)

Parameters:

• Player Index: Target player controller (0 = first player)

The plugin works at the raw input level, so both input systems receive simulated events automatically.

Simulate pressing Space Bar for Player 0.

Simulate mouse movement or gamepad stick input.

• All functions return bool indicating success/failure
• Player Index 0 targets the first player controller
• Pair press events with releases. After a test, demonstration, or replay, use Flush Pressed Keys to clear remaining state and prevent stuck keys
• Nodes can also be called in the editor, but require a valid PlayerController; without one, input cannot be injected as intended
• Axis inputs automatically adapt to current frame rate
• Check Output Log for detailed simulation messages (LogSimpleInputSimulator)

Open Edit → Project Settings, select the SimpleInputSimulator settings page, and set Language to English or Chinese. English is the default. Available user-facing UI, tooltips, notifications, and functional logs update immediately without restarting the editor. Public API names and module startup/shutdown logs remain in English.

For usage questions or collaboration, please visit the contact page.

• Contact: Contact and collaboration

Use Blueprint nodes to simulate keys and axis input, then clear the state when finished.

Parameters and usage notes:

• Supports all FKey values, covering keyboard, mouse, and gamepad
• Compatible with both Legacy Input and Enhanced Input
• Supports PlayerIndex to specify a local player
• All nodes are marked CallInEditor = true, allowing direct testing in the editor
• Axis input automatically obtains DeltaTime, so you do not need to pass it manually

Input is injected into the UE input system through PlayerController::InputKey.

Instead of sitting at the computer and repeating clicks, write a script to run the sequence automatically:

BeginPlay:
  Delay(1.0)                              // 等待初始化
  SimulateKeyInput(W, true)               // 前进
  Delay(2.0)
  SimulateKeyInput(W, false)              // 停止
  SimulateKeyInput(SpaceBar, true)        // 跳跃
  SimulateKeyInput(SpaceBar, false)
  SimulateKeyInput(LeftMouseButton, true) // 攻击
  SimulateKeyInput(LeftMouseButton, false)
  FlushPressedKeys()                      // 清理状态

These action sequences can be used for smoke testing and regression testing.

Let the character perform actions automatically in the tutorial interface while the player watches:

1. Show the on-screen prompt "Press W to move forward"
2. SimulateKeyInput(W, true)    → The character starts walking automatically
3. Wait 2 seconds
4. SimulateKeyInput(W, false)   → Stop
5. Show the on-screen prompt "Well done! Next, try jumping"

The demonstration uses the in-game character to execute an input sequence.

Let AI control a character through the input system to verify the complete path from input to behavior:

// AI 决策：向右移动
SimulateAxisInput(Gamepad_LeftX, FVector(1.0, 0, 0))

// AI 决策：开火
SimulateKeyInput(Gamepad_RightTrigger, true)

This lets you inspect how simulated input is processed into character behavior.

Combine the plugin with a recording system to capture a player’s input sequence (Key + timestamp), then replay it frame by frame with SimulateKeyInput. Uses include:

• Bug reproduction: QA records actions and programmers replay them to locate the problem
• Performance analysis: Replay identical actions on different hardware to compare frame rates
• Highlight replays

When nobody is operating the game at an exhibition, let it demonstrate highlights automatically:

// 循环播放预设的操作序列
while (bDemoMode):
  PlayDemoSequence()  // 内部用 SimulateKeyInput 驱动
  Delay(5.0)          // 每段演示间隔 5 秒

Test a two-player game alone by controlling the second player with a script:

// 玩家1：手动操作
// 玩家2：脚本控制
SimulateKeyInput(W, true, 1)         // 玩家2 前进
SimulateAxisInput(MouseX, ..., 1)    // 玩家2 转向

Copy the plugin folder into the project’s Plugins directory and restart the editor.

Search for the Simple Input Simulator category in Blueprints and drag out the nodes to use them directly.

• Simulated input requires a valid PlayerController; ensure the game is running
• Release keys after pressing them, otherwise they remain pressed
• Call FlushPressedKeys after testing to clear remaining state