Swapping out textures in M4 has been made as simple as possible, with the use of Material Instancing. Every single texture used within the Auto and Baked Materials are able to be swapped out with any texture of your choice. Unreal Engine’s Megascans library is a great source of new textures and is completely compatible with M4.
To begin swapping out any texture, first click on the terrain, and within the details panel, scroll down until you see a parameter called “Landscape Material”. Click the magnifying glass icon next to the material and it will take you to the Material Instance that is currently being used for the terrain within the Content Browser. Double click on the Material Instance that is assigned to the terrain.
Double clicking on the Material Instance within your Content Browser will open up a new window containing settings for the Landscape’s assigned Material Instance. Contained within the Material Instance are many advanced settings (the number values don’t need to be touched at all if you’re looking for a simplified experience), Layer Painting parameters and all of the textures that the material uses in order to achieve its visual result.
It’s best practice to backup a material instance before you start heavily modifying it, or just make a copy and apply the copy to the landscape, as to not lose any of the default setups for the Blueprint presets. The “Terrain Customization Settings” portion of the Magic Map Material Blueprint will still work with any new Material Instance copy you assign to it.
If you switch performance presets, or biomes, after swapping out the textures make sure to swap out the textures within that new preset also. Each performance preset as well as each biome has their own Material Instance which is driving them.