You built a room. Walls, furniture, all of it — and somehow it still looks cheap.
One cause is that the sky is still at its default. VRChat worlds often show the outdoors, and the sky's impression becomes the world's impression.
This article covers swapping the sky and blurring the distance with fog. Only two places to touch, and the mood changes dramatically.
What You'll Learn
- Why the sky changes the room's brightness
- How to swap the Skybox
- The three fog modes, and which suits beginners
- Why fog color follows the sky
Start from having read baking lights.
The sky is a light source, not a backdrop
A Skybox is something like a sphere wrapped around the world. It's the background you see whichever way you turn, drawn as though infinitely far away.
That much is explained by "background image." But in Unity's default settings, the sky's color also affects the room's brightness.
The Lighting settings have an Environment Lighting entry, and its source defaults to "Skybox." In other words, the sky itself acts as part of the lighting.
So this happens.
| Change the sky to | And in the room |
|---|---|
| Blue sky | Everything gets brighter with a blue cast |
| Sunset | Even the shadows take on orange |
| Night sky | Everything gets dark and blue-black |
"Changing the sky changed the inside of the room" is a sign it's working correctly. Knowing this makes mood-setting far easier. Picking a sky first is often faster than adjusting indoor lights one at a time.
There are several kinds of Skybox. Choosing between them is simple.
| Kind | When to use it |
|---|---|
| Procedural | Builds a sky from settings alone. When you want to dial in the time of day numerically |
| Cubemap / 6 Sided | Applies prepared sky images. When you want a photographic sky |
| Panoramic | Applies a single 360-degree photo |
Procedural is enough at first. You can set the sun's position and the sky's density numerically, so you get the sky you want without preparing images.
Hands-On: Change the sky, blur the distance
Try three skies in a garden scene and put fog over the distance.
1. Set up a scene you can compare in
Place one floor and line up a few Cubes on it standing in for buildings. Put them at three distances: near, middle, and far. That's how you'll see the fog work.
| Name | Position |
|---|---|
NearBox | (0, 1, 5) |
MidBox | (3, 1, 20) |
FarBox | (-3, 1, 60) |
Keep one Directional Light in the scene.
Press Play and confirm all three are visible from where you stand.
2. Swap the sky
Open "Window → Rendering → Lighting" and look at the Environment tab.
At the very top is the Skybox Material field. That's the swap point.
First make your own sky. Right-click in the Project window, choose "Create → Material," and name it MySky. In the Shader field, pick Skybox → Procedural.
Drag MySky into Skybox Material.
Procedural has three main fields.
| Field | Effect |
|---|---|
| Sun Size | The sun's size |
| Atmosphere Thickness | Air density. Higher moves toward sunset |
| Sky Tint | The sky's color itself |
Make three skies and compare them.
| Sky to build | Suggested settings |
|---|---|
| Day | Atmosphere Thickness 1.0, Sky Tint a pale blue |
| Evening | Atmosphere Thickness 2.5, Sky Tint a pale orange |
| Night | Sky Tint a deep navy, Exposure lowered |
The sun's direction comes from the scene's Directional Light rotation. Laying the Rotation flat gives evening light.
Watch the room's brightness change along with each swap. That's the most important experience in this article.
When the brightness is too strong or not enough, raise or lower Intensity Multiplier in the same Environment tab.
3. Blur the distance with fog
Scrolling down the same Environment tab, there's a Fog entry. Check it to enable it.
| Field | Setting |
|---|---|
| Fog Color | Close to the sky's color |
| Fog Mode | Linear |
| Start | 20 |
| End | 80 |
Press Play and compare.
| What to look at | Expected result |
|---|---|
NearBox (5m) | Clearly visible |
MidBox (20m) | Just beginning to whiten |
FarBox (60m) | Considerably hazed |
The further away, the more it dissolves into the sky's color. That's fog's job.
4. Match the fog color
Now deliberately set the fog color to grey.
The sky is blue, but the distance hazes to grey. The far scenery reads as separate, and the picture looks unnatural.
Bring it close to the sky's color and distant objects dissolve into the sky naturally.
Sample the fog color from the sky. When you change the sky, change the fog with it. Always treat these two as a pair.
A sunset sky wants pale orange fog; a night sky wants deep navy.
The three fog modes
Fog Mode offers three choices.
| Mode | How it applies | Where it fits |
|---|---|---|
| Linear | Thickens in a straight line from the start distance to the end distance | Most situations. You set it by number |
| Exponential | Thickens sharply with distance | Thick fog, underwater |
| Exponential Squared | Thickens even more sharply | Fog so thick you can't see ahead |
When in doubt, Linear. You decide the distances yourself: "haze starts at 20 meters and reaches full at 80." The other two are governed by a single density number, so hitting the look you want takes practice.
Fog has a side benefit too. Since the distance becomes invisible, you no longer have to draw beyond it. In large outdoor worlds it helps both the look and the weight.
Common Pitfalls
- Changed the sky but the room stays dark → Environment Lighting's Source is set to something other than Skybox
- The room is too bright → Lower Intensity Multiplier
- Fog does nothing → Check that Fog is enabled and that Start isn't too far out
- Only the distance looks off-color → The fog color doesn't match the sky
- It doesn't match the baked lighting → You changed the sky without rebaking the lights
- Some objects get no fog → That material's shader doesn't support fog. Standard shaders do
Bonus: Good to Know Up Front
- Decide the sky first: Picking a sky ahead of furniture and lighting speeds up every color decision after it, because the world's overall cast is settled first
- You'll need to rebake: Changing the sky changes the ambient light, so rebake if you've baked lighting. It won't look the same as before
- It matters for indoor-only worlds too: Sky through a window, light through a skylight. Even in a design where the sky isn't visible, it still works as ambient light
- Fog creates a sense of distance: Just hazing the far view makes space feel larger. Even in a small world, fog in the distance adds depth
- It's useful all over: A morning park, a rooftop at dusk, a night street, a foggy forest. Changing just sky and fog turns the same terrain into a different place
Summary
Sky and fog are the two dials that set the mood.
- The sky is a light source, not a backdrop. Change it and the room's brightness changes
- What you swap is Skybox Material in Lighting's Environment tab
- Fog is easiest with Linear. Set it by start and end distances
- Match the fog color to the sky. Always treat these two as a pair
The question to ask while building is: "What time of day is this world?" Settle that and the sky and fog settings mostly settle themselves.
To refine how light falls, go to baking lights. To add particle effects, go to making motes of light with particles.