Blender 2.80
I have two meshes (curves extruded along paths) that I have combined with ⌃ Ctrl + J union. Now I am trying to subtract a third mesh using a Boolean Modifier. When I select difference, I don't see the difference result. When I select union it sort of renders a difference but not exactly either.
I have had this happen while performing union on a couple of other extruded meshes but was able to fix it by removing the terminal edges of the mesh and extruding the terminal face before performing union. In this case, I am stumped. I don't know whats causing the problem.
First question I have is the union of the two extruded meshes. I was hoping to see just some exterior faces on the boundary of the two meshes. Rather it looks like the super imposition of the two.
When I subtract the third mesh from the union, the boolean tools are freaking out. Is this because of the issue I am pointing out in the first question.
I have looked for non manifold geometry and loose geometry but haven't found any. I did not find any duplicate vertices to join. I have already performed a limited dissolve.
Can someone help.
When third mesh is subtracted I expect a channel but it renders as an union