Baking lights in Unreal Engine is essential for creating high-quality, performance-optimized scenes. This guide walks you through the complete process—from setup to troubleshooting—using the latest tools in UE 5.4 and beyond. Perfect for game devs, arch viz artists, and filmmakers working in 2026.
Key Takeaways
- Light baking saves performance: Baked lighting removes real-time calculations, boosting frame rates in games and interactive experiences.
- Use Lightmass for high-quality results: Unreal’s built-in global illumination system creates realistic shadows and soft lighting when baked.
- Static lighting requires static meshes: Only objects marked as “Static” can receive baked lighting—dynamic objects need light probes or Lumen.
- UVs matter for lightmaps: Properly unwrapped UVs prevent lighting artifacts and ensure even light distribution.
- Baking takes time—plan ahead: Complex scenes may take minutes to hours; use progressive CPU/GPU baking for faster iteration.
- Test early and often: Preview baked lighting frequently to catch issues before final bake.
- Combine baked and real-time lighting: Use baked lights for static environments and Lumen or dynamic lights for moving objects.
Introduction: Why Bake Lights in Unreal Engine?
If you’re building a game, architectural visualization, or cinematic experience in Unreal Engine in 2026, lighting is one of the most powerful tools at your disposal. But real-time lighting—while flexible—can be a performance killer, especially on lower-end hardware or in complex scenes. That’s where baking lights comes in.
Baking lights means pre-calculating how light interacts with your scene and saving that data into textures called lightmaps. Once baked, these lights don’t require real-time computation, which means smoother performance and better visuals—without the GPU strain.
In this guide, we’ll walk you through the entire process of baking lights in Unreal Engine 5.4 and later versions (as of 2026). Whether you’re a beginner or an experienced developer, you’ll learn how to set up your scene, configure lighting, bake with Lightmass, and troubleshoot common issues. By the end, you’ll be able to create stunning, performance-optimized environments with confidence.
What Is Light Baking?
Visual guide about How to Bake Lights in Unreal Engine
Image source: mir-s3-cdn-cf.behance.net
Before diving into the steps, let’s clarify what light baking actually means.
When you bake lights, Unreal Engine calculates how light bounces off surfaces, casts shadows, and creates ambient occlusion—then stores that information in textures. These textures are applied to your meshes at runtime, so the engine doesn’t have to compute lighting on the fly.
This is especially useful for:
– Static environments (like buildings, landscapes, or interiors)
– Scenes with complex lighting setups
– Projects targeting consoles or mobile devices
– Arch viz and pre-rendered cinematics
Baked lighting gives you cinematic-quality results with minimal runtime cost. However, it only works for static objects. Anything that moves—characters, vehicles, swinging doors—needs real-time lighting (like Lumen) or light probes to blend seamlessly.
Prerequisites: Setting Up Your Scene
Before you start baking, make sure your project and scene are properly configured. Skipping this step can lead to poor results or failed bakes.
1. Use the Right Project Settings
Start with a project that supports baked lighting. In 2026, Unreal Engine 5.4+ offers excellent support for both baked and real-time global illumination (Lumen). However, if you’re focusing on baked lighting, you may want to disable Lumen temporarily to avoid conflicts.
To do this:
– Go to Edit > Project Settings > Rendering
– Under Global Illumination, set Lumen Global Illumination to Disabled
– Ensure Lightmass is enabled (it should be by default)
This ensures Unreal uses Lightmass for baking instead of relying on real-time solutions.
2. Mark Objects as Static
Only static meshes can receive baked lighting. If your objects are set to “Movable” or “Stationary,” they won’t be included in the bake.
To fix this:
– Select your mesh in the viewport
– In the Details panel, find the Mobility dropdown
– Change it to Static
Pro Tip: Use the search bar in the Details panel to quickly find “Mobility” if it’s buried under other settings.
3. Prepare Your UVs for Lightmaps
Baked lighting uses a special UV channel (UV1) to store lightmap data. If your meshes don’t have proper UVs, you’ll see stretching, dark spots, or flickering.
Here’s how to check and fix UVs:
– Select your static mesh
– Open the Static Mesh Editor
– Go to UVs and ensure UV Channel 1 exists and is unwrapped
– If not, click Generate Lightmap UVs (found under the UV menu)
Unreal can auto-generate lightmap UVs, but for best results, manually unwrap them in a 3D app like Blender or Maya. Aim for minimal overlap and even texel density.
4. Set Up Your Lighting
Now it’s time to place your lights. For baking, use:
– Directional Light: Simulates the sun. Great for outdoor scenes.
– Point Light: Emits light in all directions from a point.
– Spot Light: Directional light with a cone shape.
– Rect Light: Emits light from a rectangular area (great for windows or panels)
Make sure all lights are set to Static or Stationary:
– Static lights are fully baked.
– Stationary lights can move or change intensity, but their shadows and indirect lighting are baked.
Avoid using Movable lights unless they’re truly dynamic—they won’t bake.
Configuring Lightmass for Baking
Lightmass is Unreal’s global illumination system. It calculates how light bounces around your scene and stores the results in lightmaps.
1. Open Lightmass Settings
To access Lightmass settings:
– Go to Window > World Settings
– Scroll down to the Lightmass section
Here, you’ll find key settings that control bake quality and performance.
2. Adjust Key Lightmass Parameters
Let’s go over the most important settings:
Indirect Lighting Quality
– Controls the number of light bounces.
– Default is 1. Increase to 3–5 for higher quality (but longer bake times).
– For interiors, 3–4 is usually sufficient.
Indirect Lighting Smoothness
– Blurs the lightmap to reduce noise.
– Default is 0.8. Increase to 1.0 for smoother results.
Environment Intensity
– Boosts the brightness of sky lighting.
– Useful for outdoor scenes. Start at 1.0 and adjust as needed.
Num Indirect Lighting Bounces
– How many times light bounces off surfaces.
– Default is 2. Increase to 4–6 for richer ambient lighting.
Compress Lightmaps
– Reduces memory usage by compressing lightmap textures.
– Enable this unless you need maximum quality.
Use Ambient Occlusion
– Adds soft shadows in corners and crevices.
– Enable for more realistic results.
Pro Tip: For quick iterations, lower the quality settings. For final bakes, increase them for cinematic results.
3. Set Lightmap Resolution
Each static mesh has a Lightmap Resolution setting (found in the Details panel). This controls how detailed the baked lighting is.
– Low resolution (e.g., 32–64): Fast bake, blocky shadows.
– High resolution (e.g., 256–512): Sharp shadows, longer bake time.
Aim for:
– 64–128 for small props
– 128–256 for walls and floors
– 256–512 for hero assets (main characters, key architecture)
Avoid going above 512 unless absolutely necessary—it increases memory usage and bake time significantly.
How to Bake Lights: Step-by-Step
Now that your scene is ready, it’s time to bake.
1. Open the Build Menu
In the top toolbar, click Build > Build Lighting Only. This starts the baking process.
Alternatively, use Build > Build All if you also want to rebuild navigation, geometry, and other systems.
2. Choose Your Baking Method
In 2026, Unreal Engine supports two main baking methods:
Progressive CPU Lightmass
– Uses your computer’s CPU.
– Slower but more stable.
– Good for final bakes.
GPU Lightmass (Experimental)
– Uses your graphics card for faster baking.
– Requires a compatible NVIDIA RTX GPU.
– Great for quick iterations.
To enable GPU Lightmass:
– Go to Edit > Editor Preferences > Lighting
– Check Enable GPU Lightmass
Note: GPU Lightmass may not support all features (like certain light types or complex materials). Test thoroughly.
3. Monitor the Bake Process
Once you start the bake, a progress window will appear. You’ll see:
– Percentage complete
– Estimated time remaining
– Current task (e.g., “Building static lighting”)
For complex scenes, baking can take anywhere from a few minutes to several hours. Be patient—rushing leads to artifacts.
4. Review the Results
After the bake completes, inspect your scene:
– Look for dark spots, light leaks, or flickering
– Check shadow sharpness and color accuracy
– Walk through the scene in-game to test performance
If something looks off, don’t panic—most issues can be fixed with adjustments.
Common Issues and Troubleshooting
Even with careful setup, baking can go wrong. Here’s how to fix the most common problems.
1. Light Leaks
Symptom: Light bleeding through walls or floors.
Cause: Gaps between meshes or incorrect collision.
Solution:
– Ensure all static meshes are sealed (no gaps).
– Use Blocking Volumes to block light where needed.
– Increase Lightmap Resolution on affected meshes.
2. Dark or Overexposed Areas
Symptom: Parts of the scene are too dark or washed out.
Cause: Poor light placement or incorrect intensity.
Solution:
– Adjust light intensity and color.
– Add fill lights or emissive materials for balance.
– Increase Indirect Lighting Quality for better bounce.
3. Flickering or Noise
Symptom: Shadows or lighting flicker when moving the camera.
Cause: Low lightmap resolution or overlapping UVs.
Solution:
– Increase Lightmap Resolution.
– Check UVs for overlap in the Static Mesh Editor.
– Enable Indirect Lighting Smoothness.
4. Long Bake Times
Symptom: Baking takes hours.
Solution:
– Lower Indirect Lighting Quality during testing.
– Use GPU Lightmass if available.
– Reduce lightmap resolution on non-critical objects.
– Split large scenes into sub-levels and bake separately.
5. Missing Shadows
Symptom: Objects don’t cast shadows.
Cause: Lights set to “Movable” or objects not marked as “Static.”
Solution:
– Ensure lights and objects are set to Static or Stationary.
– Check that Cast Shadow is enabled on lights and meshes.
Optimizing Baked Lighting for Performance
Baked lighting is great for performance—but only if done right. Here’s how to keep your scene running smoothly.
1. Use Light Probes for Dynamic Objects
Since baked lighting only works on static objects, dynamic characters and items won’t receive baked shadows. To fix this, use Light Probes.
Place Lightmass Importance Volume around your scene, then add Light Probe Groups where dynamic objects will appear. These capture baked lighting data and apply it to moving objects.
2. Combine with Lumen for Hybrid Lighting
In 2026, many projects use a hybrid approach: baked lighting for static environments and Lumen for dynamic elements.
To do this:
– Keep Lumen enabled for real-time global illumination
– Bake static lights as usual
– Use Stationary lights for objects that need both baked and real-time shadows
This gives you the best of both worlds: performance and flexibility.
3. Optimize Lightmap Memory
High-resolution lightmaps use more VRAM. To reduce memory usage:
– Use Compress Lightmaps in Lightmass settings
– Lower resolution on distant or small objects
– Use texture atlasing to combine lightmaps
4. Test on Target Hardware
Always test your baked scene on the hardware you’re targeting—whether it’s a high-end PC, console, or mobile device. Baked lighting should run at 60+ FPS with minimal hitches.
Best Practices for 2026 Workflows
As of 2026, Unreal Engine has evolved significantly. Here are some modern best practices:
1. Use Nanite with Baked Lighting
Nanite allows you to use high-poly models without performance loss. When combined with baked lighting, you get photorealistic detail with smooth performance.
Just remember: Nanite meshes still need proper lightmap UVs and must be marked as Static.
2. Leverage Virtual Shadow Maps
Even with baked lighting, you may want real-time shadows for dynamic objects. Virtual Shadow Maps (VSMs) in UE 5.4+ provide high-quality shadows with low cost.
Use VSMs for characters and vehicles, and baked shadows for the environment.
3. Automate with Python Scripts
For large projects, manually setting lightmap resolutions and baking can be tedious. Use Unreal’s Python API to automate tasks like:
– Setting lightmap resolution based on object size
– Baking multiple levels in sequence
– Validating UVs before bake
Example script snippet:
import unreal
for actor in unreal.EditorLevelLibrary.get_all_level_actors():
if actor.get_class().get_name()