Hello Mr_Neverm0re,
I think the problem with your meshes are that they’re not vertex sharing, each tri has it’s own set of vertices to comprise itself, even if their corners share the same location with other corners of other tris, effectively separating them.
In order to get rid of this you’d have to weld the vertices together, in Blender v2.8 you’d have to make sure that the vertices are welded together, i.e. not using a edge split modifier, the object and mesh are both smooth shaded and any vertices which share their location with an other one, are merged together (i.e. Mesh > Merge by Distance).
Hope that helps. Just let me know, if I was too unclear or if you have any questions.
Regards,
Vecherka.