hmmm, still have no idea how ti fix my map. I have 2 "walls" like that
....w
w/.... and want to close them putting another "w(wall)" inside those w|w|/w making something like a boat (i want to make a boat). I've done that, but it don't looks too good(used fix button : ). The problem is that walls are not so simple, so connecting them properly is also not so simple.
Actualy everything looks right, don't know where is the problem, just invalid solid.