You built a dark corridor and the mood works, but now you cannot tell where to go. Brighten everything and the darkness itself disappears.
Rather than raising brightness across the board, give your lights roles. A wall lamp sets the space's impression, a light hits the far door, and your feet stay visible. This article adds three lights to a simple corridor and tunes for keeping the dark while showing what matters .
What You'll Learn
- Choosing among Directional, Point, Spot, and Rect Light
- The difference between Lumen's bounce and the light itself
- Locking exposure so light changes are comparable
- A hands-on turning off each of three lights to confirm its role
Choose a light by how it emits
Add lights to a level from "Lights" in "Place Actors". Start with the four types that light things directly.
| Light | How it emits | Where it fits |
|---|---|---|
| Directional Light | Parallel rays from one direction | Sunlight or moonlight |
| Point Light | Spreads in all directions from a point | Bulbs, torches, campfires |
| Spot Light | Spreads in a cone from a point | Flashlights, guiding to a door |
| Rect Light | Has a rectangular emitting face lighting forward | Ceiling panels, window light |
A Directional Light behaves like a distant sun, so moving it does not change the light's direction . Changing its rotation changes where and how far shadows stretch. A low angle produces long, evening-like shadows.
Point, Spot, and Rect Lights illuminate their surroundings from their position. Start by learning Intensity and Attenuation Radius separately.
Attenuation Radius is the upper bound on how far that light's direct light reaches. Increasing it widens the reachable range, but distant surfaces are not guaranteed to be bright. Falloff with distance and occluders along the way both matter.
The spherical range in the diagram is the marker shown when the light is selected. No sphere is drawn during play. Lumen's bounce can also appear beyond that direct-light range.
A Rect Light's rectangular face also appears in reflections on metals. Shadow softness depends on the shadowing method used, so "a bigger rectangle always gives softer shadows" is not guaranteed.
Lumen computes where the light goes next
Light reaching a wall straight from a light source is direct light , and light bouncing off walls and floors to light elsewhere is indirect light . A floor by a window brightening, and that bounce faintly revealing the ceiling, is that kind of light.
The mechanism computing indirect light is GI (global illumination) . UE5's Lumen updates GI as lights and objects change and also computes surrounding reflections.
White light hitting a red wall can tint the nearby floor red, because light carrying the wall's color returns to the floor. Lumen does not invent light sources; it computes where the light that exists goes next . It is not a feature that brightens a room with no light in it.
Check these two entries under "Edit" → "Project Settings" → "Rendering".
| Setting | What Lumen handles there |
|---|---|
| Dynamic Global Illumination Method | Bounce from walls and floors |
| Reflection Method | Reflections on metals and floors |
The hands-on below uses a desktop Third Person template with those two set to Lumen . Not every template and rendering path defaults to that, so check after creating the project.
How it differs from a Sky Light
A Sky Light carries light from the sky and surrounding environment. It lights outdoor shade with light from the sky.
Lumen accounts for buildings blocking sky light, so placing a Sky Light does not uniformly brighten a closed cave's depths. And if a setting captures the surrounding sky but the sky is removed, or a setting takes an environment image left blank, you will not get the light you expect.
We do not use a Sky Light in this corridor, so we can compare the three placed lights. Try it combined with a Directional Light as the sun when building outdoors.
Mobility: what you can change at runtime
Mobility in a light's Details panel decides whether it can move and whether its color and intensity can change at runtime. When using precomputed lighting, it also affects how it participates in that computation.
| Mobility | Runtime changes | How we treat it |
|---|---|---|
| Static | No movement, color, or intensity change | Unused. Static lights' light is disabled when Lumen GI is enabled |
| Stationary | Position fixed, color and intensity changeable | Usable with Lumen, but we standardize on Movable |
| Movable | Position, orientation, color, and intensity changeable | All three lights use this |
Precomputing light and storing it in images is called baking . The image storing static background light is a lightmap . Enabling Lumen GI means that baked lightmap light is not used.
We tune with Movable and Lumen, watching changes as we make them. No "Build Lighting" bake is needed. Cost also depends on light count and shadow settings, so do not judge light or heavy from the Mobility name alone.
Lock exposure to make changes comparable
You brighten a light and it looks brighter, then a moment later the brightness returns. That may be Auto Exposure at work.
Exposure is how bright the camera makes the screen look. Auto exposure can express glare settling as you step from a dark room into daylight.
If exposure moves while you change lights, it is hard to tell what changed the brightness. So the hands-on fixes exposure before tuning lighting.
- Search "Place Actors" for
Post Process Volumeand add one. - Turn on "Infinite Extent (Unbound)" in the Details panel.
- Open "Lens" → "Exposure", tick the checkbox left of "Metering Mode", and choose
Auto Exposure Histogram. - Tick both checkboxes left of "Min EV100" and "Max EV100" and set both to
1.0. - Tick the checkbox left of "Exposure Compensation" and set it to
0.
A Post Process Volume is an Actor holding screen brightness and color adjustments together. Turning Unbound on applies the settings to the whole level rather than only inside the box. Each checkbox on the left means "this Volume overrides that setting".
Matching Min and Max removes the range auto exposure can adjust in. 1.0 is a starting point for this prototype, not a value fitting every level. Lowering the fixed value brightens things and raising it darkens them.
In older projects showing "Min Brightness" and "Max Brightness", setting both to the same value also locks it. Those numbers mean something different from EV100, though, so the same 1.0 will not give the same brightness.
The editor viewport can also be on its own exposure. Enable "Game Settings" under the view mode's "Exposure" and confirm the final look during Play. Adjustments like Local Exposure, which balance parts of the screen, can remain as separate settings.
Hands-On: show the corridor and door with three lights
We build a corridor where the wall side is warmly lit, the far door catches your eye, and your feet stay faintly visible. It is a prototype for thinking about cave or warehouse lighting, so Cubes are shape enough.
1. Build a corridor of consistent size
In a desktop Third Person template project, create "File" → "New Level" → "Empty Level" and save it as L_LightingPractice . It has no sky or lights to start with.
Confirm the two Lumen entries and set "Global Illumination" and "Reflections" to High or Epic in the viewport's "Scalability" quality settings. Lower quality settings can disable Lumen or switch to a different computation.
Use the standard Cube from "Place Actors" → "Shapes" and place these parts. The standard Cube is 100 cm per side, so a Scale of 6 is 6 m. Enter positions in "Location" and sizes in "Scale". All Rotations are 0 and the floor and walls can stay at Mobility Static . Static meshes and the Static lights above are different settings.
| Part name | Location (X, Y, Z) | Scale (X, Y, Z) |
|---|---|---|
| Floor | (0, 0, -10) | (6, 4, 0.2) |
| Ceiling | (0, 0, 310) | (6, 4, 0.2) |
| Wall_Left | (0, -210, 150) | (6, 0.2, 3) |
| Wall_Right | (0, 210, 150) | (6, 0.2, 3) |
| Wall_Back | (310, 0, 150) | (0.2, 4.4, 3) |
| Door_Target | (290, 0, 120) | (0.1, 1, 2.4) |
The floor's surface is Z=0 and the corridor is 4 m wide, 6 m long, and 3 m tall. Location numbers are in cm. Leave the negative-X near side open. Door_Target is a marker board to light; we build no opening mechanism.
Start with the Cubes' default material. We want to compare light, so do not switch to emissive or pure black materials.
Place a Player Start at (-200, 0, 100) with Rotation (0, 0, 0) . Choose BP_ThirdPersonGameMode in "World Settings" → "GameMode Override" so you can walk with the template character. Finally, place one Post Process Volume from the previous section in this level to lock exposure.
While it is too dark to place things, switching the viewport to "Unlit" helps. Unlit does not display lighting results , so return to "Lit" when checking your lighting.
2. Build a warm wall light with a Point Light
Place a Point Light and name it Light_Warm . It is a lamp toward the corridor's near end, a little away from the left wall.
| Property | Value |
|---|---|
| Location | (-50, -140, 180) |
| Mobility | Movable |
| Intensity Units | Candelas (cd) |
| Intensity | 50 |
| Attenuation Radius | 400 |
| Use Inverse Squared Falloff | On |
| Light Color | (1.0, 0.6, 0.3) in RGB |
Clicking Light Color's swatch opens a color picker. RGB are the red, green, and blue components, and the table's numbers go into the picker's R, G, and B fields. They are not 0-255 values or Hex entries.
cd (candela) is a unit of light intensity. Our numbers all use cd. "Use Inverse Squared Falloff" uses the calculation where light weakens with distance. Rather than the formula, focus on touching "intensity" and "reach" separately.
Warm color appearing on the wall and floor means this stage worked. Light icons are not displayed during play. To show a lamp body or flame, add models or effects later.
The diagram shows the three lights' rough relationship. Use each table's Location for exact placement. Place the Point Light first, then add the other two in turn.
3. Guide the eye to the far door with a Spot Light
Name a Spot Light Light_Door and aim it from the corridor's center at the far door.
| Property | Value |
|---|---|
| Location | (-50, 0, 240) |
| Rotation | Pitch (Y) -20 , Yaw (Z) 0 , Roll (X) 0 |
| Mobility | Movable |
| Intensity Units / Intensity | Candelas (cd) / 200 |
| Attenuation Radius | 700 |
| Use Inverse Squared Falloff | On |
| Inner Cone Angle / Outer Cone Angle | 15 / 25 |
| Light Color | White |
A Spot Light lights along the cone's center line shown when selected. The rotation above tilts it slightly downward toward the far door. Confirm the cone does not face the near side or bury itself in the ceiling.
Inner Cone Angle sets the bright center range and Outer Cone Angle sets where light fades out. Light weakens between them, so the difference between the two becomes the cone edge's softness. That is separate from how soft object shadows are.
The door board standing out from its surroundings means success. Not seeing the light cone itself in the air is normal. We place no fog here; we look at the light landing on the door and floor .
4. Make the near floor slightly readable with a Rect Light
The corridor's mood and goal exist by now. Add a weak fill from near the ceiling when the near floor is too dark.
| Property | Value |
|---|---|
| Name | Light_Fill (Rect Light) |
| Location | (-100, 80, 260) |
| Rotation | Pitch (Y) -90 , Yaw (Z) 0 , Roll (X) 0 |
| Mobility | Movable |
| Intensity Units / Intensity | Candelas (cd) / 5 |
| Attenuation Radius | 600 |
| Source Width / Source Height | 100 / 100 |
| Light Color | (0.65, 0.8, 1.0) in RGB |
A Rect Light lights one side. Check its orientation when selected and point it at the floor, not the ceiling. The 100 cm square here is the emitting face's size; Attenuation Radius bounds how far it reaches.
Keep the blue subtle so the Point Light's warmth and the door light stay the leads. The numbers are starting points: raise Fill's Intensity slightly if it is too dark, and lower it if the whole corridor becomes uniformly bright. Start with "Cast Shadows" on for all three.
5. Turn off one light at a time to confirm its role
Play and walk from the entrance to the door. Warmth by the wall, a standout door, and a floor you do not lose track of means it is done. The figures in this article are generated finished images, so tune actual brightness and shadows for your environment.
After checking, stop Play and compare by temporarily setting each light's Intensity to 0 . Turn off one light at a time and restore it before trying the next so you can tell the roles apart.
| Light turned off | The change to watch |
|---|---|
| Light_Warm | The wall warmth and its bounce onto surroundings fade |
| Light_Door | The door blends into its surroundings and the way ahead is hard to find |
| Light_Fill | The near floor and the character get darker |
If turning any of them off is hard to notice, another light may be too strong or that light may not reach the surface. Confirming one role at a time is easier to tune than piling on more bright light.
When light does not look as expected
Do not settle on one cause; separate whether it is a whole-screen problem or specific to one light.
| Symptom | Where to look first |
|---|---|
| Changing a light does nothing at all | Whether the viewport is Lit, whether Intensity is 0, whether Mobility is Movable |
| The wall is lit but the floor is not | Whether the light is buried in a wall or ceiling, and whether the floor is inside Attenuation Radius |
| Only Spot or Rect fails to light | The light's orientation. For Spot, whether the cone overlaps the target |
| The screen darkens back right after brightening | Exposure's Min/Max values and override checkboxes, other Volumes' or the camera's settings |
| The editor and Play differ in brightness | Whether the viewport's Exposure uses Game Settings |
| The player does not appear or cannot walk | Player Start, GameMode Override, overlap with the floor |
| Direct light exists but the bounce is weak | Lumen GI and quality settings, wall color and thickness, whether reflecting surfaces receive light |
Lumen's Software Ray Tracing traces light paths using approximated distance data to objects. It requires Generate Mesh Distance Fields under "Project Settings" → "Rendering", and switching it prompts an editor restart. Light leaks easily through walls that are too thin, so our walls are 20 cm thick Cubes.
There is also a Hardware Ray Tracing path on capable GPUs, but you do not need to switch for this introduction. Check light source, orientation, range, and exposure first, and move to rendering-path adjustments only if problems remain.
Bonus: Good to Know Up Front
Bounce and "glow bleeding" are different
Emissive materials can also light their surroundings through Lumen. Small, extremely bright faces are noise-prone, though, so pairing a light with them where you need reliable illumination is easier to tune.
Bloom , the on-screen spread around bright things, is a separate effect used in the screen's finishing pass. Keep lighting a floor separate from light appearing to bleed on screen. Material settings continue in Material Basics, and exposure and Bloom in the Post Process Volume article.
Compare appearance and cost for shadows and quality together
Adding moving lights and shadows can raise cost. Start with removing unnecessary shadows and narrowing light range to where it is needed. Turning shadows off can also cause unintended changes, such as light appearing to wrap past a wall.
Once comfortable, stop the camera in one position and compare quality settings High and Epic . Note the visual difference and the GPU time from typing stat gpu in the console. GPU time shows how long drawing the screen takes. How to read it in detail is covered in the measurement article.
There are also mechanisms like MegaLights for handling many dynamic lights, but available features vary by environment and rendering path. Aim first at being able to explain what each of this corridor's three lights shows.
Summary
When choosing a light, ask whether it comes from one direction like the sun, spreads like a bulb, or narrows onto a door. Tune intensity and reach separately, and read Lumen's bounce as that light's continuation.
Dark spaces do not need uniform brightness. Place the light needed for the way ahead, the nearby wall, and your feet, and turn each one off. Once you know "what disappears without this light", you can build lighting with roles in the next room too.
Reference: Light types and their mobility, Lumen, Auto exposure