diff --git a/crates/fj-core/src/operations/build/half_edge.rs b/crates/fj-core/src/operations/build/half_edge.rs
index e1c6074ce..bdf1abf64 100644
--- a/crates/fj-core/src/operations/build/half_edge.rs
+++ b/crates/fj-core/src/operations/build/half_edge.rs
@@ -87,6 +87,8 @@ pub trait BuildHalfEdge {
         surface: Handle<Surface>,
         core: &mut Core,
     ) -> Handle<HalfEdge> {
+        let boundary = boundary.unwrap_or_default();
+
         let half_edge = HalfEdge::unjoined(core).insert(core);
 
         half_edge.curve().clone().make_line_on_surface(
@@ -96,12 +98,9 @@ pub trait BuildHalfEdge {
             &mut core.layers.geometry,
         );
 
-        core.layers.geometry.define_half_edge(
-            half_edge.clone(),
-            HalfEdgeGeom {
-                boundary: boundary.unwrap_or_default(),
-            },
-        );
+        core.layers
+            .geometry
+            .define_half_edge(half_edge.clone(), HalfEdgeGeom { boundary });
 
         half_edge
     }
diff --git a/crates/fj-core/src/operations/build/shell.rs b/crates/fj-core/src/operations/build/shell.rs
index c0d94e47a..9062dccb3 100644
--- a/crates/fj-core/src/operations/build/shell.rs
+++ b/crates/fj-core/src/operations/build/shell.rs
@@ -92,7 +92,7 @@ pub trait BuildShell {
 
                             let curve = curve.make_line_on_surface(
                                 positions,
-                                Some(boundary),
+                                boundary,
                                 surface.clone(),
                                 &mut core.layers.geometry,
                             );
diff --git a/crates/fj-core/src/operations/geometry/curve.rs b/crates/fj-core/src/operations/geometry/curve.rs
index b4ccf2755..8418fe4a8 100644
--- a/crates/fj-core/src/operations/geometry/curve.rs
+++ b/crates/fj-core/src/operations/geometry/curve.rs
@@ -35,7 +35,7 @@ pub trait UpdateCurveGeometry {
     fn make_line_on_surface(
         self,
         points_surface: [impl Into<Point<2>>; 2],
-        points_curve: Option<CurveBoundary<Point<1>>>,
+        points_curve: CurveBoundary<Point<1>>,
         surface: Handle<Surface>,
         geometry: &mut Layer<Geometry>,
     ) -> Self;
@@ -71,11 +71,10 @@ impl UpdateCurveGeometry for Handle<Curve> {
     fn make_line_on_surface(
         self,
         points_surface: [impl Into<Point<2>>; 2],
-        points_curve: Option<CurveBoundary<Point<1>>>,
+        points_curve: CurveBoundary<Point<1>>,
         surface: Handle<Surface>,
         geometry: &mut Layer<Geometry>,
     ) -> Self {
-        let points_curve = points_curve.unwrap_or_default();
         let path = SurfacePath::line_from_points_with_coords(
             points_curve.inner.zip_ext(points_surface),
         );
diff --git a/crates/fj-core/src/operations/sweep/half_edge.rs b/crates/fj-core/src/operations/sweep/half_edge.rs
index 3e350152a..d87ac7f3d 100644
--- a/crates/fj-core/src/operations/sweep/half_edge.rs
+++ b/crates/fj-core/src/operations/sweep/half_edge.rs
@@ -133,7 +133,7 @@ impl SweepHalfEdge for Handle<HalfEdge> {
                     .unwrap_or_else(|| Curve::new().insert(core))
                     .make_line_on_surface(
                         [start, end],
-                        Some(boundary),
+                        boundary,
                         surface.clone(),
                         &mut core.layers.geometry,
                     );