I managed to create my spline building system, visible here :
But I can’t get to put a texture on it when i’m drawing it in game.
If I put in the editing viewport my static mesh used for the spline on the level, it has a texture, but in game, it does not. I tried the node “set material” etc, but nothing happen.
Looks fine at a glance. Is it safe to assume this very material is set up to work with SMCs? You said that applying it manually works so it probably is - just double checking. There is flag in the material that needs to be enabled for this to work with spline meshes.
Just to test it out, could you assign the same brick material here instead: