When you first opened Unity, you most likely noticed a vast and expansive horizon laid out behind a grid within the Scene View. Well, that is known as the “Skybox” and it is actually an amazing and fun feature that is built into Unity to allow developers to make expansive backgrounds with fluidity and ease.
Within your camera, you will find an adjustable option called “Clear Flags”. Changing this will allow you to turn the background into a Solid Color, Skybox, or more.
For the sake of this article, we will be having Skybox selected.
Now, to create your Skybox you must start by creating a new material. You can do this by simply right-clicking within your project folder and selecting “Create>Material”.
Next, you’ll want to change your material from using a Standard Shader to a Skybox and then select “6 Sided”.
Notice that you are then prompted with six different spaces to insert textures. These will represent the Sides, Top, and Bottom of your 6 sided Skybox.
Think of it as you have just placed your entire scene inside of a cube.
In order to apply the Skybox that you just created into your scene, you must go to the “Lighting” settings menu and select the “Environment” tab. Then just drag your new skybox material into the slot titled “Skybox Material”.
If you want to use baked lighting or information from your skybox’s texture to adjust your scene then you will need to make sure you change your “Environment Lighting — Source” to “Skybox”.
And there you have it; a custom skybox made from scratch!
[Bonus Tip]
You can also select “Gradient” or “Color” within “Environment Lighting — Source” to make your environmental lighting derive from specific colors.