The temporary-offset workaround (#7408, commit bd57cc8735) subtracts the
directrix centroid (`mean`) from the curve points before building the
sweep near the origin, then must add it back to restore the original
location. The restore negated the sign — `Move(-mean)` instead of
`Move(+mean)` — placing the swept solid at -mean (mirrored through the
origin) rather than its true position.
Only triggers for polyline directrixes (`is_polyhedron()`) whose centroid
is more than 100 m from the origin (`mean.norm() > 1e2`), so models
centered near the origin are unaffected. Models that keep absolute site
coordinates (e.g. many Revit/ODA IFC exports) render affected swept
solids — reinforcing bars, pipes — at a mirrored phantom location far
from the rest of the model.
Tiago Azevedo