How to Make a Light Turn on in Unreal Engine

This guide walks you through how to make a light turn on in Unreal Engine, covering static, stationary, and dynamic lighting. You’ll learn to place, configure, and animate lights using Blueprints and level design tools.

Key Takeaways

• Understand light types: Learn the differences between static, stationary, and movable lights and when to use each.
• Place lights in your scene: Use the Place Actors panel to add point, spot, or directional lights to your level.
• Adjust light properties: Modify intensity, color, temperature, and attenuation for realistic or stylized lighting.
• Control lights with Blueprints: Use Blueprint scripting to turn lights on and off dynamically during gameplay.
• Optimize performance: Choose the right light mobility settings to balance visual quality and performance.
• Troubleshoot common issues: Fix problems like lights not appearing or incorrect shadows.
• Enhance with post-processing: Use post-process volumes to improve overall lighting atmosphere.

Introduction: Why Lighting Matters in Unreal Engine

Lighting is one of the most important aspects of creating immersive and visually appealing environments in Unreal Engine. Whether you’re building a dark horror dungeon, a bright outdoor landscape, or a futuristic sci-fi corridor, knowing how to make a light turn on in Unreal Engine is essential. Lights don’t just illuminate your scene—they set the mood, guide the player, and enhance realism.

In this guide, you’ll learn everything from placing your first light to scripting dynamic lighting effects using Blueprints. We’ll cover different types of lights, how to adjust their settings, and how to make them respond to gameplay events. By the end, you’ll be able to create professional-quality lighting that brings your levels to life.

Understanding Light Types in Unreal Engine

Before you start placing lights, it’s important to understand the three main types of lights in Unreal Engine: static, stationary, and movable. Each has its own use case and performance impact.

Static Lights

Static lights are baked into the scene during the lighting build process. They don’t change during gameplay and are the most performance-efficient. Use them for environments where lighting doesn’t need to change—like a fixed sun in an outdoor level or ambient room lighting.

To use static lights:

• Set the light’s Mobility to Static in the Details panel.
• Place the light in your level.
• Build lighting by going to Build > Build Lighting Only.

Because static lights are precomputed, they produce high-quality shadows and lighting with minimal runtime cost. However, they cannot be turned on or off during gameplay unless you use workarounds like hiding the light actor.

Stationary Lights

Stationary lights offer a balance between performance and flexibility. They have baked shadows but can change intensity, color, and be toggled on and off during gameplay. This makes them ideal for lights that need to respond to player actions—like a flickering lamp or a switchable overhead light.

To use stationary lights:

• Set Mobility to Stationary.
• Adjust intensity and color as needed.
• Use Blueprints to control when the light turns on or off.

Stationary lights are a great choice for most interactive lighting needs. They provide realistic shadows and can be dynamically controlled without heavy performance costs.

Movable Lights

Movable lights are fully dynamic and can change position, intensity, and color in real time. They are the most flexible but also the most performance-intensive. Use them for effects like a flashlight, moving vehicle lights, or cinematic sequences.

To use movable lights:

• Set Mobility to Movable.
• Place the light and adjust settings.
• Control the light via Blueprints or animation.

Movable lights are perfect for dynamic scenes but should be used sparingly to avoid frame rate drops.

How to Place a Light in Your Level

Now that you understand the types of lights, let’s walk through the process of placing a light in your level.

Step 1: Open the Place Actors Panel

In the Unreal Editor, go to the Modes panel (usually on the left side of the screen). Click on the Place tab. Here, you’ll find a list of actors you can add to your level, including lights.

Step 2: Choose a Light Type

Under the Lights category, you’ll see several options:

• Point Light: Emits light in all directions from a single point. Great for lamps, bulbs, or general room lighting.
• Spot Light: Emits light in a cone shape. Ideal for flashlights, stage lights, or focused illumination.
• Directional Light: Simulates a distant light source like the sun. Affects the entire level uniformly.
• Rect Light: Emits light from a rectangular area. Useful for fluorescent panels or soft ambient lighting.

For this guide, we’ll use a Point Light as an example.

Step 3: Drag and Drop the Light

Click and drag the Point Light into your level. Position it where you want the light to be—for example, above a table or in the center of a room.

Step 4: Adjust the Light’s Position and Rotation

Use the translation (move) and rotation gizmos to fine-tune the light’s placement. You can also type in exact coordinates in the Details panel for precision.

Configuring Light Properties

Once your light is in place, it’s time to customize its appearance and behavior.

Intensity and Color

In the Details panel, find the Light section. Here, you can adjust:

• Intensity: Controls how bright the light is. Measured in lumens for point and spot lights. Start with 1000–5000 for indoor lights.
• Light Color: Sets the color of the light. Click the color swatch to open the color picker. Use warm tones (orange/yellow) for cozy interiors and cool tones (blue/white) for clinical or outdoor scenes.
• Temperature: Alternatively, use Kelvin temperature (e.g., 3000K for warm, 6500K for daylight). This is more realistic for natural lighting.

For example, a warm indoor lamp might use an intensity of 3000 and a color temperature of 2700K.

Attenuation and Falloff

Attenuation determines how far the light reaches and how it fades over distance.

• Attenuation Radius: Sets the maximum distance the light affects. Increase this for larger areas.
• Light Falloff Exponent: Controls how quickly the light dims. A value of 2 is standard (inverse square law). Lower values make the light fade more slowly.

Tip: If your light isn’t reaching far enough, increase the Attenuation Radius. If it’s too harsh, lower the falloff exponent slightly.

Shadow Settings

For stationary and movable lights, you can control shadow quality:

• Cast Shadows: Enable this to allow the light to cast dynamic shadows.
• Shadow Bias: Adjust to fix shadow acne (dark spots on surfaces). Start with 0.01 and tweak as needed.
• Dynamic Shadow Distance: For directional lights, set how far shadows are rendered.

Note: Static lights generate shadows during the lighting build, so shadow settings are less critical.

How to Make a Light Turn On and Off with Blueprints

Now for the fun part—making your light respond to gameplay! Using Blueprints, you can turn lights on and off based on player actions, timers, or events.

Step 1: Create a Blueprint Actor

Right-click in the Content Browser and select Blueprint Class. Choose Actor as the parent class. Name it BP_SwitchableLight.

Step 2: Add a Light Component

Open the Blueprint. In the Components panel, click Add Component and search for Point Light (or Spot Light). Name it MyLight.

Step 3: Set Up the Event Graph

In the Event Graph, right-click and add the following nodes:

• Event BeginPlay: This triggers when the level starts.
• Toggle Light: We’ll create a custom function to turn the light on and off.

To create a toggle function:

1. Right-click in the graph and select “Add Function.” Name it ToggleLight.
2. Inside the function, drag from the execution pin and search for “Set Intensity.”
3. Connect the MyLight component to the Target input.
4. Use a Boolean variable (e.g., IsLightOn) to track the state.
5. Use a Branch node to check if IsLightOn is true or false.
6. If true, set intensity to 0 (off). If false, set it to your desired value (e.g., 3000).
7. Flip the IsLightOn variable after each toggle.

Step 4: Trigger the Toggle

You can trigger the toggle in many ways:

• On Player Interaction: Use a Trigger Box. When the player overlaps it, call ToggleLight.
• On Key Press: Use the Input Action node (e.g., “E” key) to call ToggleLight.
• On Timer: Use a Timer node to automatically turn the light on and off every few seconds.

Example: To turn the light on when the player presses “E”:

1. Add an Input Action (e.g., “Interact”) in Project Settings > Input.
2. In the Event Graph, add “InputAction Interact.”
3. Connect it to the ToggleLight function.

Step 5: Place the Blueprint in Your Level

Compile and save the Blueprint. Drag BP_SwitchableLight into your level. Test the game—press “E” near the light to toggle it on and off.

Advanced Lighting Techniques

Once you’ve mastered basic lighting, try these advanced techniques to enhance your scenes.

Using Light Functions

Light Functions allow you to project textures or patterns onto surfaces using light. For example, you can simulate a flickering flame or a stained-glass window effect.

To use a Light Function:

• Create a Material with a texture (e.g., a flicker pattern).
• In the light’s Details panel, assign the material to the Light Function slot.
• Adjust the scale and intensity for the desired effect.

Adding Light Propagation Volume (LPV)

For realistic indirect lighting in dynamic scenes, enable Light Propagation Volume (LPV) in Project Settings > Rendering > Lighting. This allows movable lights to bounce light realistically, but it can be performance-heavy.

Using IES Profiles

IES (Illumination Engineering Society) profiles simulate real-world light fixtures. Import an IES file and assign it to a light to replicate the exact beam pattern of a lamp or streetlight.

Troubleshooting Common Lighting Issues

Even experienced developers run into lighting problems. Here’s how to fix the most common ones.

Light Doesn’t Appear in Game

Possible causes:

• The light’s intensity is set to 0.
• The light is outside the camera’s view or too far away.
• The light is set to Static but lighting hasn’t been built.
• The light is hidden or disabled in the level.

Solution: Check the light’s settings, rebuild lighting if static, and ensure it’s enabled.

Shadows Look Blocky or Pixelated

This is usually due to low shadow map resolution.

Solution:

• Increase the shadow map resolution in Project Settings > Rendering > Shadows.
• For directional lights, adjust the Dynamic Shadow Distance.
• Use Contact Shadows for finer detail.

Performance Drops with Multiple Lights

Too many movable or stationary lights can hurt performance.

Solution:

• Use static lights where possible.
• Limit the number of dynamic lights.
• Use Light Culling Volumes to disable lights outside the player’s view.

Light Flickers or Z-Fighting

This happens when two lights or surfaces are too close.

Solution:

• Move the light slightly away from geometry.
• Adjust the Shadow Bias or Normal Bias.
• Ensure no overlapping light sources.

Optimizing Lighting for Performance

Good lighting shouldn’t come at the cost of performance. Follow these tips to keep your game running smoothly.

Use Light Mobility Wisely

• Static lights for non-changing environments.
• Stationary lights for interactive but non-moving lights.
• Movable lights only when necessary (e.g., flashlights).

Limit Dynamic Lights

Each dynamic light adds to the render cost. Use Light Channels to control which lights affect which objects.

Use Lightmass Settings

For static lighting, adjust Lightmass settings in World Settings:

• Indirect Lighting Quality: Higher values improve quality but increase build time.
• Static Lighting Level Scale: Lower values increase lightmap resolution.

Balance quality and build time based on your project needs.

Enhancing Lighting with Post-Processing

Post-processing can dramatically improve the look of your lighting.

Add a Post Process Volume

Place a Post Process Volume in your level and enable Unbound so it affects the entire scene.

Adjust Exposure and Color Grading

• Use Auto Exposure to simulate how the human eye adjusts to light.
• Apply color grading to set the mood—cool tones for horror, warm for romance.

Enable Bloom and Lens Flares

These effects make bright lights glow realistically. Adjust intensity and threshold to avoid overuse.

Conclusion: Mastering Light in Unreal Engine

Learning how to make a light turn on in Unreal Engine opens up endless creative possibilities. From simple static room lights to complex dynamic systems controlled by Blueprints, lighting is a powerful tool for storytelling and immersion.

We’ve covered the basics of placing and configuring lights, the differences between static, stationary, and movable types, and how to script interactive lighting. We’ve also explored advanced techniques like light functions and post-processing, plus troubleshooting and optimization tips.

Remember, great lighting is both an art and a science. Experiment with different settings, test in-game, and don’t be afraid to iterate. With practice, you’ll be able to create stunning, atmospheric environments that captivate players.

Now go light up your world—one pixel at a time.