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Landscapes - Nanite Tessellation

Tessellation is the ability to displace the surface of a mesh or landscape as it is rendered to create the appearance of more detail than the mesh contains. Nanite tessellation requires Unreal Engine 5.4 or higher.

Background​

This is part of a series of articles about landscapes, other articles are:

Landscapes - Building GDAL
Landscapes - Material Concepts
Landscapes - Nanite Tessellation
Landscapes - Using Real Location Data
Landscapes - World Partition and Tiling

Setup​

The plugin "Nanite Displaced Mesh" need to be enabled for nanite tessellation to work.

Edit DefaultEngine.ini and add these settings:

[/Script/Engine.RendererSettings]
r.Nanite.ProjectEnabled=1
r.Nanite.AllowTessellation=1
r.Nanite.Tessellation=1

Material Setup​

Make a new material then in the details panel:

  • set "Use Material Attributes" to true
  • set "Enable Tessellation" to true
  • set "Used with Nanite: to true

Use a texture set which has a displacement channel or texture. Here I used the Quixel Soil Clay surface with High Quality - the medium and low quality versions of this surface (and maybe most Quixel surfaces) do not contain a displacement texture.

To get a similar texture search Fab for quixel "rocky soil" and make sure it has Displacement listed in the Maps:

width90

Drag the textures onto the material and connect them to make a material like this:

width90

Texture Setup​

Open the displacement texture.

If it is completely white like this:

width5010

Change the "Compression Settings" property to "Grayscale (G8/16, RGB8 SRGB)" and it should now look more like a height map:

width5010

As you change the compression setting the "Sampler Type" property on the Texture Sample node which reads this texture will automatically change to "Grayscale".

Depending on the texture, the material might have an error saying:

[SM6] (Node TextureSample) Sampler type is Grayscale, should be Linear Grayscale for /Game/Fab/Megascans/Surfaces/Soil_Clay_pjEm30/High/T_pjEm30_4K_H.T_pjEm30_4K_H

If this happens change the "Sampler Type" property on the Texture Sample node to "Linear Grayscale".

Landscape Setup​

In the landscape details panel set "Enable Nanite" to true and then press the "Build Data" button, this might take 10-20 seconds to complete:

width5010

The landscape should now show the texture with too much displacement like this:

This can be fixed by editing the material or material instance and changing the Displacement Scaling | Magnitude property to a lower value:

width5010

This makes the landscape look more sensible:

Viewing Tessellation​

If we switch to the wireframe view of the landscape we see this:

If we turn the "Enable Tessellation" property off in the material instance and look at the Nanite Visualization | Triangles view we see that the triangles which get rendered correspond to the triangles in the landscape:

If we turn tessellation on, we see all the triangles created by the tessellation process:

References​