Don't superimpose inner and outer walls or more simply unselect the Recompute walls option and it will work properly.
In real build, the inner wall (isolating) is againts the outter wall.
There is no glue in sh3d...
One cm to simulate the glue.
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Evil progresses when good people do nothing!
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SH3D 7.1 and nothing else - W11 64b in 4K
