Have tried intersect, combine & split on this section and able to do more simple ones.
For this I tried to cut the center clean as a surface before thickening.
It does split, I can select the internal faces but it doesn't give a separation on the faces, it's all one piece.
thx for thoughts on how to stage doing this. I did think it should be easier to cut as a surface, can't get the inner part separated to be able to delete it.
Message was edited by: Tom Mallard on the same type of problem.