I am looking for a way to create a mesh that uses decals as the materials. In the UE City Sample for example, the SM_DECAL_19 instance is a static mesh that uses multiple decals as materials.
I don’t know how if it can be done inside a static mesh, but you can make a blueprint.
Import your static mesh, the floor plane in this case, and in Unreal Content Browser right click and create a Blueprint Class, and choose “Actor Class”.
Although it is not the most optimized solution really, since if you want an object that is repeated X times and has a same detail in each part, the best thing to do is put it in the texture.