I can't maintain a constant/smooth texture/color w/ modular meshes or meshes w/ multiple elements


I can’t maintain a constant/smooth texture/color with modular meshes or meshes with multiple elements. For example, on this basic rock model with 2 elements (see below), if I put a material on it, even a very basic and uniform texture, the seam is visible between the 2 parts. In this tutorial (, the guy can fix this easy very easily : He simply reduces the Static Lighting Level. But in my case, it does’nt work. On discord, some guys tell me the issue could also come from bad UVs. I tried my best to redo a more clean UV unwrap (I’m not very good into UV unwrap, I must admit…) but it still does’nt work. This is the rock model and his UVs :

Someone can help me ?

Have you gone through the doc page on UV Unwrapping, and the one about generating lightmap UVs in Unreal?

Is that one mesh or two separate meshes, that are close to each other? Because, it looks like, as if this is a mesh error, where the smoothing doesn´t work or is deactivated for the vertexes. Or maybe the vertexes/points in that area are doubled for some reason and the polygons not connected.
How does the wireframe look like in this area? Does this line go along some polygon edges?