Terrain Layers

A Terrain Layer is an Asset that defines a TerrainThe landscape in your scene. A Terrain GameObject adds a large flat plane to your scene and you can use the Terrain’s Inspector window to create a detailed landscape. More info
See in Glossary’s surface qualities. A Terrain Layer holds TexturesAn image used when rendering a GameObject, Sprite, or UI element. Textures are often applied to the surface of a mesh to give it visual detail. More info
See in Glossary and other properties that the Terrain’s Material uses to render the Terrain surfaces. Because Terrain Layers are Assets, you can easily reuse them on multiple Terrain tiles.

You can add Textures to the surface of a Terrain to create coloration and fine detail. Terrain GameObjectsThe fundamental object in Unity scenes, which can represent characters, props, scenery, cameras, waypoints, and more. A GameObject’s functionality is defined by the Components attached to it. More info
See in Glossary are usually large, so it is best to use a base Terrain Layer with Textures that tile over the surface and repeat seamlessly. You can use multiple Terrain Layers, each with different Textures, to build up interesting, varied Terrain surfaces.

The first Terrain Layer you apply to a Terrain automatically becomes the base layer, and spreads over the whole landscape. In addition, you can paint areas with other Terrain Layers to simulate different ground surfaces, such as grass, desert, or snow. To create a gradual transition between grassy countryside and a sandy beach, you might choose to apply Textures with variable opacity.

Creating Terrain Layers

To create a Terrain Layer directly in the Terrain InspectorA Unity window that displays information about the currently selected GameObject, asset or project settings, allowing you to inspect and edit the values. More info
See in Glossary, click the paintbrush icon in the toolbarA row of buttons and basic controls at the top of the Unity Editor that allows you to interact with the Editor in various ways (e.g. scaling, translation). More info
See in Glossary at the top of the Terrain Inspector, and select Paint Texture from the drop-down menu. At the bottom of the Terrain Layers section, click the Edit Terrain Layers button, and choose Create Layer.

When you select Create Layer, Unity opens the Select Texture2D window. Here, choose the image to use as the Diffuse channel of the Terrain Layer. To assign a Normal MapA type of Bump Map texture that allows you to add surface detail such as bumps, grooves, and scratches to a model which catch the light as if they are represented by real geometry. More info
See in Glossary or Mask Map Texture to your Terrain Layer, select the corresponding Terrain Layer in the Project view, and use its Inspector window.

Alternatively, to create a Terrain Layer Asset that isn’t automatically associated with a Terrain, right-click the Project window, and select Create > Terrain Layer from the context menu. Then, configure the various properties in the Inspector window for your new Terrain Layer.

For information about how the number of Terrain Layers affects renderingThe process of drawing graphics to the screen (or to a render texture). By default, the main camera in Unity renders its view to the screen. More info
See in Glossary performance, see Rendering performance. Even assigned Terrain Layers that you do not actually paint onto the Terrain tile might impact the rendering performance.

Adding Terrain Layers

Initially, a Terrain has no Terrain Layers assigned to it. By default, it uses a checkerboard Texture until you add a Terrain Layer.

After you create a Terrain Layer in your Project, click the Edit Terrain Layers button and select Add Layer to open the Select TerrainLayer window. Double-click on a Terrain Layer in this window to add it to your Terrain.

Terrain Layer properties

Depending on the Material that is set in the Terrain Settings, as well as the Render Pipeline that is currently in use, you might see different options and properties in the Inspector.

Texture painting

Unity applies the first Terrain Layer you add to the entire landscape. If you add multiple Terrain Layers, use the Paint Texture tool to apply subsequent Textures to your Terrain.

If you add a new Terrain tile without any Terrain Layers, and paint on it, the system automatically adds the selected Terrain Layer to that new Terrain tile. Because this is the first Terrain Layer, that Texture becomes the base layer, and fills the entire Terrain tile.

In the Terrain Inspector, under Brushes, there is a box that displays the available Brushes, along with the Brush Size and Opacity options underneath. See Creating and Editing Terrains for more information about these tools.

Rendering performance

The number of Terrain Layers you assign to a Terrain tile might impact the performance of the renderer. The maximum recommended number of Terrain Layers depends on which render pipeline your Project uses.

• If your Project uses the Universal Render Pipeline (URP) or Built-in Render Pipeline, you can use four Terrain Layers per Texture pass, with no limit on the number of passes. This means that although you are allowed to use as many Terrain Layers as you want, each pass increases the time spent rendering the Terrain. For maximum performance, limit each of your Terrain tiles to four Terrain Layers.

• If your Project uses the High Definition Render Pipeline (HDRP), you can add up to eight Terrain Layers per Terrain tile, and the system renders them in a single pass. No additional passes are possible. If you add more than eight Terrain Layers, they appear in the Unity Editor, but are ignored at run time.

• 2021–01–27 Page amended

• Updated information about Color Tint and Opacity as Density properties