Add existing material into landscape material

Hello!

I have a landscape material with some different simple layers (grass, stone m.m.) for my low poly game but want to add a water material to my landscape material, so I can paint rivers on my landscape. All the materials are from a package I bought on Epics Marketplace. Is it possible to add the water material into the layer blend? Please see the pictures.

Thanks a lot!

Perhaps as a material function, or a material parameter collection. In a material function, use a Make Material Attributes node to connect to the base properties as it would be in a regular material. It might require using a Break Material Attributes node too. Do the reading on those nodes to see how it works, or watch a tutorial or two for help building it correctly. Then the output of the material function would probably plug in the Layer Water of the Layer Blend.

You do not want to blend in water onto your landscape. Put it either in a volume or on a plane. Otherwise you will get an uneven very strange look, and will lose a lot of functionality, ex: Showing landscape through water.