Baking light in Unreal Engine 4 is a powerful technique to improve performance and create realistic, static lighting in your scenes. This guide walks you through the entire process—from setting up your scene to troubleshooting common issues—so you can achieve stunning visuals with optimized rendering.
Key Takeaways
- Understand the difference between real-time and baked lighting: Baked lighting pre-calculates light data for static objects, reducing GPU load and improving frame rates.
- Properly prepare your scene before baking: Ensure all static meshes are correctly set to “Static” mobility and UVs are unwrapped for lightmaps.
- Use Lightmass settings wisely: Adjust quality, resolution, and indirect lighting settings to balance visual fidelity and bake time.
- Leverage Lightmap Density visualization: Use this tool to identify areas with poor or excessive lightmap resolution and fix them before baking.
- Optimize for performance and visual quality: Baked lighting is ideal for environments where lighting doesn’t change, such as architectural visualizations or open-world games.
- Troubleshoot common baking errors: Fix issues like light leaks, dark spots, or missing shadows by checking UVs, lightmap density, and lightmap settings.
- Stay updated with Unreal Engine 4 best practices: Even in 2026, UE4 remains widely used, and mastering lighting techniques ensures your projects stand out.
How to Bake Light in Unreal Engine 4: A Complete Guide for 2026
If you’re working on a game, architectural visualization, or cinematic scene in Unreal Engine 4 (UE4), lighting plays a crucial role in creating immersion and realism. While real-time lighting offers dynamic flexibility, it can be performance-heavy—especially on lower-end hardware. That’s where baked lighting comes in. By pre-calculating how light interacts with static objects, you can achieve beautiful, consistent lighting with minimal runtime cost.
In this comprehensive guide, you’ll learn how to bake light in Unreal Engine 4 like a pro. Whether you’re a beginner or an experienced developer, we’ll walk you through every step—from scene preparation to troubleshooting common issues. By the end, you’ll be able to create stunning, performance-optimized environments that look great and run smoothly, even in 2026.
Let’s dive in!
What Is Baked Lighting in Unreal Engine 4?
Visual guide about How to Bake Light in Unreal Engine 4
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Before we get into the how-to, let’s clarify what baked lighting actually means. In UE4, lighting can be either real-time or baked. Real-time lighting is calculated on the fly as the player moves through the scene. It’s great for dynamic effects like flickering lights or moving shadows, but it demands more from your GPU.
Baked lighting, on the other hand, is precomputed. The engine calculates how light bounces off surfaces, casts shadows, and creates ambient occlusion—then stores that data in textures called lightmaps. These lightmaps are applied to static objects during runtime, so the GPU doesn’t have to calculate lighting in real time.
This makes baked lighting ideal for:
– Static environments (like buildings, landscapes, or interiors)
– Scenes with complex lighting setups
– Projects targeting lower-end hardware or mobile platforms
In short, if your scene doesn’t need moving lights or dynamic shadows, baking your lighting is a smart move.
Step 1: Prepare Your Scene for Baking
You can’t just hit “bake” and expect perfect results. Proper preparation is key. Here’s how to get your scene ready.
Set Object Mobility to Static
Only objects marked as Static can have their lighting baked. If an object is set to Movable or Stationary, it won’t receive baked lighting.
To check and change mobility:
1. Select the object in your scene.
2. In the Details panel, find the Mobility dropdown under the Transform section.
3. Choose Static.
Pro Tip: If you have objects that need to move during gameplay (like doors or props), use Stationary mobility. Stationary lights can still cast dynamic shadows but can also contribute to baked indirect lighting.
Unwrap UVs for Lightmaps
Baked lighting relies on lightmaps, which are textures stored in a special UV channel. Every static mesh needs a properly unwrapped UV channel (usually UV Channel 1) for lightmaps.
If your mesh doesn’t have a lightmap UV:
1. Open the mesh in your 3D modeling software (like Blender or Maya).
2. Unwrap the UVs for Channel 1, ensuring no overlapping and minimal stretching.
3. Re-import the mesh into UE4.
In UE4, you can check if a mesh has lightmap UVs:
– Select the mesh.
– In the Details panel, under Lightmap Coordinate Index, make sure it’s set to 1 (or the correct channel).
– If the value is -1, the mesh doesn’t have valid lightmap UVs.
Warning: Overlapping UVs or poor unwrapping can cause light leaks or dark spots. Always double-check your UVs before baking.
Organize Your Level
A clean, organized level makes baking easier and more predictable. Group related objects, name them clearly, and remove any unnecessary geometry. This helps you troubleshoot faster if something goes wrong.
Also, consider using Lightmass Importance Volume to focus baking quality on areas the player will actually see. This saves time and improves performance.
Step 2: Set Up Your Lights
Now that your scene is ready, it’s time to place and configure your lights.
Choose the Right Light Types
For baked lighting, use:
– Directional Light: Simulates sunlight. Great for outdoor scenes.
– Point Light: Emits light in all directions from a single point. Ideal for lamps or ceiling lights.
– Spot Light: Emits light in a cone. Perfect for flashlights or stage lighting.
– Sky Light: Captures ambient light from the sky and bounces it into the scene.
Set the Light Mobility to Static for all lights you want to bake. Movable lights won’t contribute to baked lighting.
Adjust Light Settings
Each light has settings that affect how it bakes:
– Intensity: Controls brightness. Use realistic values (e.g., 1000–5000 for indoor lights).
– Light Color: Affects mood and realism. Warm tones for interiors, cool for exteriors.
– Indirect Lighting Intensity: Boosts bounced light. Increase this for softer, more natural lighting.
– Cast Shadows: Enable this to allow the light to cast baked shadows.
Example: For a cozy living room, use a warm Point Light with Indirect Lighting Intensity set to 1.5. This creates soft, inviting shadows and realistic light bounce.
Use Sky Light for Ambient Illumination
A Sky Light captures the sky and environment to provide realistic ambient lighting. To use it:
1. Place a Sky Light in your scene.
2. Set its Mobility to Static.
3. In the Details panel, set Source Type to Screenshot or Specified Cubemap.
4. If using Screenshot, make sure your skybox is properly set up.
Sky Light is essential for outdoor scenes and helps eliminate dark corners in interiors by simulating bounced light from the sky.
Step 3: Configure Lightmass Settings
Lightmass is UE4’s global illumination system. It calculates how light bounces around your scene. Proper Lightmass settings ensure high-quality baked lighting without excessive bake times.
To access Lightmass settings:
1. Go to Window > World Settings.
2. In the World Settings panel, expand the Lightmass section.
Here are the key settings to adjust:
Static Lighting Level Scale
This controls the resolution of the lightmap. Lower values mean higher quality but longer bake times.
– Default: 1.0
– High Quality: 0.5 (for final builds)
– Fast Preview: 2.0 (for testing)
Tip: Use 2.0 while testing, then drop to 0.5–0.75 for final baking.
Num Indirect Lighting Bounces
This determines how many times light bounces around the scene. More bounces = more realistic lighting.
– Default: 2
– Recommended: 4–6 for high-quality scenes
Higher values increase realism but also bake time.
Indirect Lighting Quality
This affects the accuracy of indirect lighting calculations.
– Default: 1.0
– High Quality: 2.0–3.0
Use higher values for final builds, lower for testing.
Compress Lightmaps
Enable this to reduce lightmap file size. It’s usually safe to leave on, but disable it if you notice artifacts.
Environment Intensity
Boosts the brightness of ambient lighting. Useful for dark scenes.
Step 4: Bake the Lighting
Now for the moment of truth—baking your lighting.
Open the Build Menu
1. Go to Build > Build Lighting Only.
2. UE4 will start calculating the lighting.
Note: Baking can take anywhere from a few minutes to several hours, depending on scene complexity and Lightmass settings.
Monitor the Progress
A progress bar will appear in the bottom-right corner. You can also check the Output Log (Window > Developer Tools > Output Log) for detailed messages.
If the bake fails, check the log for errors like missing UVs or invalid light settings.
Use Lightmap Density Visualization
After baking, use the Lightmap Density view mode to check quality:
1. Press Alt + 3 or go to View Mode > Optimization Viewmodes > Lightmap Density.
2. Green areas are ideal. Red means too high resolution (wasteful), blue means too low (blurry lighting).
If you see blue areas, increase lightmap resolution for those meshes:
– Select the mesh.
– In the Details panel, increase the Lightmap Resolution value (e.g., from 64 to 128).
Step 5: Optimize and Refine
Baking is just the start. Now you need to optimize and refine your scene.
Reduce Lightmap Resolution Where Possible
High-resolution lightmaps increase memory usage. Use lower resolutions for small or distant objects.
Use Lightmass Importance Volume
This volume tells Lightmass to focus quality on important areas (like where the player walks). Place it around key zones to improve performance.
Combine Static Meshes
Use Merge Actors (Edit > Merge Actors) to combine multiple static meshes into one. This reduces draw calls and improves performance.
Test on Target Hardware
Always test your baked scene on the hardware you’re targeting. A scene that looks great on a high-end PC might struggle on a console or mobile device.
Troubleshooting Common Baking Issues
Even with careful preparation, things can go wrong. Here’s how to fix the most common problems.
Light Leaks
Symptom: Light bleeding through walls or floors.
Solution:
– Ensure all meshes are sealed (no gaps).
– Check that overlapping geometry isn’t causing issues.
– Increase lightmap resolution for problem areas.
Dark or Black Areas
Symptom: Parts of the scene are unnaturally dark.
Solution:
– Check that lights are set to Static.
– Increase Indirect Lighting Intensity.
– Add more lights or use a Sky Light.
Blurry or Pixelated Shadows
Symptom: Shadows look low-res or blocky.
Solution:
– Increase lightmap resolution.
– Lower Static Lighting Level Scale.
– Ensure UVs are properly unwrapped.
Bake Takes Too Long
Symptom: Baking takes hours.
Solution:
– Increase Static Lighting Level Scale (e.g., to 2.0).
– Reduce Num Indirect Lighting Bounces.
– Use Lightmass Importance Volume to limit baking area.
Best Practices for 2026 and Beyond
Even in 2026, Unreal Engine 4 remains a powerful tool for lighting. Here are some best practices to keep in mind:
– Use baked lighting for static environments: It’s still the best way to achieve high-quality, performant lighting.
– Combine with real-time effects: Use baked lighting for base illumination and real-time lights for dynamic elements (like flickering candles).
– Stay organized: Name your lights and meshes clearly. Use folders in the Content Browser.
– Document your settings: Keep notes on Lightmass settings for different project types.
– Keep learning: UE4 updates may introduce new lighting features. Stay informed through official docs and community forums.
Conclusion
Baking light in Unreal Engine 4 is a game-changer for performance and visual quality. By pre-calculating lighting data, you can create stunning, realistic environments that run smoothly on a wide range of devices.
In this guide, you’ve learned how to:
– Prepare your scene with static objects and proper UVs
– Set up and configure lights for baking
– Adjust Lightmass settings for quality and speed
– Bake lighting and visualize lightmap density
– Troubleshoot common issues like light leaks and dark spots
Whether you’re building a game, a virtual tour, or a cinematic experience, mastering baked lighting will elevate your work. So fire up Unreal Engine 4, follow these steps, and start creating beautifully lit worlds today.