Landscape Materials

Unreal Engine (UE) provides several landscape-specific Material Blueprint nodes that can help improve the textures for your Landscape. You can use the nodes alongside any other material in UE.

Layer Weights and Ordering

Landscape materials operate as a blend between multiple layers, where painted blend weights control the influence of each layer. 

Each layer is identified by a (case-insensitive) name that gets used in one of the landscape-specific material nodes (e.g. Landscape Layer Sample, Landscape Layer Blend, etc.). The nodes allow the material to access a specific weightmap of a specific target layer.

To be paintable, the layer needs to be created and associated with a Landscape Layer Info asset. For more information, see Target Layers. It is okay to create a target layer in the landscape and not use it in the landscape material. However, if a material looks for a layer name that has no target layer entry in the landscape, its weight will always be considered zero.

In the Blueprints editor, the material graph determines how the weights are interpreted to achieve the blended result. The blending method defines how the landscape uses those weights in the final result.

There are two possible blending modes: Weight Blending and Alpha Blending. You can use these methods together to create different effects, such as snow on top of your grass and dirt layers.

Landscape-Specific Material Nodes

Inside the Material Editor, there are several specific nodes that you can use with the Landscape system. You can find these nodes by right-clicking and searching the context sensitive menu, or by searching in the Palette menu.

Landscape Layer Blend Node

The Landscape Layer Blend node blends together multiple per-layer values, such as texture samples or materials. Layers with higher blend weights have more influence on the blended result.

To add a new layer, click the plus (+) icon.

After you’ve added layers to the node, the Layer Names appear in the LandscapeLayerBlend node. The node has the following inputs:

The Landscape Layer Blend node has the following inputs and outputs:

Landscape Layer Blend Types

The Landscape Layer Blend node has three types of blend modes. Each different Layer Blend mode is used to achieve a different result.

Blend Mode	Function
LB Weight Blend	Implements a weighted blend between all LB Weight Blend layers. This type is not order dependent.
LB Alpha Blend	Implements an alpha-blended overlay on top of the LB Weight Blend and LB Height Blend layers. Each LB Alpha Blend layer is applied in the order they appear in the list. For example, painting snow over rock and grass occludes both, but erasing snow reveals the rock and grass beneath it.
LB Height Blend	This is the same as LB Weight Blend, but also adds detail to the transition between layers based on a height map. For example, you can have dirt appear in the gaps between rocks at the layer transition point, instead of just smoothly blending between rock and dirt. The dirt appears in the gaps between rocks at the layer transition point, creating a smooth transition where the layers meet.

Adding a Landscape Layer Node

The LandscapeLayerBlend node automatically blends multiple layers together using either alpha blending or alpha blending with a height-based offset. The height-based offset lets a layer blend with other layers based on a heightmap input.

1. In the Material Editor, add a LandscapeLayerBlend node.

2. In the Details panel, next to Layers, click the plus icon (+) to add a layer.

   

3. Expand the layer to view its properties.

4. Change the Layer Name to a descriptive name for the layer, for example, Snow.

5. Determine whether you want the layer to be alpha blended or height blended, and set the Blend Type accordingly.

   

6. Add as many additional layers as you want for your Landscape Material. Rename them, and set their Blend Types appropriately.

7. Connect the LandscapeLayerBlend node's output to the Base Color input of your material's base node.

8. Add Texture Sample nodes, and connect their main outputs to the Layer inputs of the LandscapeLayerBlend nodes. Alternatively, you can create a more complex material network and connect it to the Landscape Layer Blend Layer input. For any height-blended layers, connect the Texture Sample's alpha output to the LandscapeLayerBlend's Height input.

When you are done, your Landscape material network should look something like this:

For more information on the Landscape Layer Blend node, see Landscape Layer Blend Technical Information.

Landscape Layer Sample Node

The Landscape Layer Sample node returns the weight value associated with a given target layer. Its result is a value between 0.0 (when the target layer is not used) and 1.0 (when the target layer is fully painted), that you can then use at will in its material computations.

Landscape Layer Coords Node

The Landscape Layer Coords node generates UV coordinates used for mapping the Landscape material onto Landscapes.

This node has the following options:

Landscape Layer Switch Node

You can use the Landscape Layer Switch node to exclude some material operations when a specific layer is not contributing to a region of the Landscape. You can use this to optimize your material by removing calculations that are not necessary when a layer's weight is zero.

This node has the following options:

Landscape Layer Weight Node

You can use the Landscape Layer Weight node to access layer weights and implement your own custom blending solution in the material graph. The output returns (Base + Layer * LayerWeight). By chaining multiple Landscape Layer Weight nodes together, you can produce a weighted sum that blends between the specified layers.

You can directly access the LayerWeight value without modification by setting the Base value to 0 and the Layer value to 1.0.

This node has the following options:

Adding a Landscape Layer Weight Node

1. In the Material Editor, add a LandscapeLayerWeight node.

   

2. In the Details panel, change the Parameter Name to a descriptive name for the layer, for example, Rock.

   

   All layer names must be unique. It is recommended to name your layers with a descriptive name that indicates the layer’s contents.

3. Add additional Landscape Layer Weight nodes, until you have one for each layer that you want your material to have. This example uses two LandscapeLayerWeight nodes.

4. Add and connect your Texture Samples or material network expressions to your Landscape Layer Weight nodes.

5. Add a LandscapeLayerCoords node and set the UV titling. Connect it to the Texture Sample nodes.

6. Connect each Layer node's output pin to the Base pin of the next layer node, while leaving the first layer node's Base pin unconnected.

7. Connect the last Layer node's output pin to the Base Color input of the NewMaterial node.

You should have something similar to the example below:

Landscape Visibility Mask Node

The Landscape Visibility Mask node outputs the visibility value of the landscape. The output is the visibility mask value. The value is 0.0 where the landscape is transparent and 1.0 where the landscape is visible.

On a standard landscape, landscape visibility requires the material to use a Masked Opacity Blend Mode, as the landscape shader needs to sample the visibility weightmap to discard pixels that are not visible enough. In order to do this, you have to connect the Landscape Visibility Mask material node to the Opacity Mask. This is more costly performance-wise, and should be avoided as much as possible on the global landscape material.

The landscape system is able to automatically detect the regions (landscape components) where visibility information is present. It can then override the material instance’s blend mode, only in those regions, in order to limit where a masked material is actually used. You need to leave the landscape material’s Blend Mode to Opaque, but connect the Opacity Mask (even if it appears greyed out), like this:

Landscape Layer Blend Technical Information

Landscape layer nodes behave similar to a Static Switch Parameter node. This switches between using one branch of the material and another. Each component of the Landscape has its own Material Instance Constant created from the main Landscape material, which is applied to only that component.

If a Landscape component does not use a specific layer, the subtree of nodes connected to the layer is discarded. This reduces the complexity, letting the material applied to the Landscape contain any number of texture samples, as long as it is within the limits set by the shader model.

Using this method, you can create a main Landscape material that contains every texture or material you need, while keeping the final result within the parameters allowed by the hardware.

Please note that currently most RHIs support shared texture samplers, which means that there’s no hard constraint about how many layers can be used on a given landscape component. The exception being ES3.1 (mobile), which still has a hard limit in terms of sampler count (16), across all texture accesses in the material. Hence, if the game is planned to ship on such a platform, it’s important to make sure that the number of landscape layers remains low, since a new weightmap texture will be added every 4 target layers (1 target layer per channel of an RGB8 texture). This means another texture sampler will be added (on top of all the textures that might get sampled by the target layer’s shader code path).  For more information, see Mobile Landscape Materials. 

Landscape Layer Blend Issues

When you use the LB Height Blend mode for multiple Landscape layers, you may find black spots on your Landscape where different layers meet. LB Height Blend works by managing the blend factor, or weight, for the layer, using the specified height value. When multiple layers are painted on an area and are set to LB Height Blend, the layers painted in a particular area can simultaneously have a 0 height value, so the desired blend factor for each layer becomes 0.

Because there is no specific ordering, black spots can appear because no layers have any contributions in that area. When you blend a Normal map, even more black spots can appear, because this blending results in a Normal value of (0,0,0), which is invalid and causes lighting issues. If this happens, paint the area with a material with a non-zero weight.

In the left image, all layers are LB Height Blend, causing some areas to be black. On the right, the red "1" layer has been changed to use LB Alpha Blend.

Below is an example of the properties of the Landscape Layer Blend node for all the layers being blended together. The Soil layer has its blend mode set to LB Alpha Blend, while the other layers have theirs set to LB Height Blend. This is to stop the issue mentioned above from happening.

To delete a layer, click the dropdown arrow to the right of the layer's element number, and select Delete.

Mobile Landscape Materials

You can use any number of Landscape layers, as long as you have enough Texture Sampler nodes. The Landscape layer allocation uses the Feature Level Switch material node, letting a single PC or console Landscape material also have a mobile version. The following image shows how the Landscape in Fortnite Battle Royale looks when used for mobile devices.

Assigning Materials to Landscapes

After creating a Landscape material, assign the material to a Landscape actor in your level.

1. In the Content Browser, locate the Landscape material that you want to use.

2. Either in the viewport or using the World Outliner, select the Landscape.

3. In the Details panel for the Landscape, locate the Landscape Material option, and click the dropdown to select a material.