Root cause of the F4 multi-floor bug: "Import factory" always creates a NEW factory, so importing floor 2 produced a second stacked factory (scene-2-f4) instead of a second floor of f4 — pins dropped to ground, the floor selector didn't appear (had to patch all.json by hand).
Add an import option: add the imported scene as a FLOOR (floor id + Y offset) of an existing factory, not a new one.
Acceptance: importing two scenes into one factory yields one factory with floors [l1, l2]; the viewer shows the floor selector + hide-above works, with no manual JSON fix.
Root cause of the F4 multi-floor bug: "Import factory" always creates a NEW factory, so importing floor 2 produced a second stacked factory (
scene-2-f4) instead of a second floor off4— pins dropped to ground, the floor selector didn't appear (had to patchall.jsonby hand).Add an import option: add the imported scene as a FLOOR (floor id + Y offset) of an existing factory, not a new one.
Acceptance: importing two scenes into one factory yields one factory with floors
[l1, l2]; the viewer shows the floor selector + hide-above works, with no manual JSON fix.