Sheet metal: rules as expressions (Thickness, K-factor, bend radius, reliefs, gaps; may use parameters), sheet bodies kept as flat patterns and sewn folded from exact faces (new kernel::sew), Flange (base, edge with height to the outer face, angle, inside/outside/middle, several edges at once with corners closed to the rule gap, contour from an open chain), Hem, Unfold/Refold with cut-outs that follow the bends, Convert to Sheet Metal, flat pattern with bend lines and bend table, DXF export; recipes: sm_flange, sm_hem, unfold/refold, rule edits (oracle 67-76 all pass)

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01AS5Tn3xieewUSg3uxrMVdL

crates/kernel/src/lib.rs

@@ -26,6 +26,7 @@ mod offset;
 mod ops;
 mod polybool;
 mod polyhedron;
+mod sew;
 mod step;
 mod step_in;
 mod step_out;
@@ -40,6 +41,7 @@ pub use meshbody::{MAX_TRIANGLES, mesh_body};
 pub use ops::{BoolOp, boolean, split_by_plane, transform, transform_matrix};
 pub use polybool::planar_boolean;
 pub use polyhedron::{HalfSpace, convex_polyhedron, draft, offset_faces, shell};
+pub use sew::{EdgeSpec, FaceSpec, SurfSpec, sew};
 pub use step::step_export;
 pub use step_in::{ImportedBody, StepImport, StepNode, step_import, step_import_shared, step_validate};
 pub use step_out::{ExportBody, ExportProduct, StepHeader, step_export_bodies, step_export_products};