I was making a terrain, actually making a path on the terrain,so I have to combine two materials together with their own displacement maps.
Now I know how to do it for those normal materials, I just weight paint the terrain to create a vertex color, add an node called Attribute and chose the vertex color. Therefore I get two materials on one plane except the displacement material.
But how to do it with displacement? It's in the modifier so I can't use the Attribute node for it, or can I?
And in the displace modifier, I do find a place I can choose to put a vertex group(not the vertex color) to have two displacement maps, but it is not the Vertex Color that I weight painted before.