diff --git a/crates/fj-core/src/algorithms/approx/cycle.rs b/crates/fj-core/src/algorithms/approx/cycle.rs
index c2495fb0b..f975686d3 100644
--- a/crates/fj-core/src/algorithms/approx/cycle.rs
+++ b/crates/fj-core/src/algorithms/approx/cycle.rs
@@ -32,7 +32,10 @@ impl Approx for (&Cycle, &Handle<Surface>) {
             .half_edges()
             .iter()
             .map(|half_edge| {
-                approx_half_edge(half_edge, surface, tolerance, cache, geometry)
+                let boundary = geometry.of_half_edge(half_edge).boundary;
+                approx_half_edge(
+                    half_edge, surface, boundary, tolerance, cache, geometry,
+                )
             })
             .collect();
 
diff --git a/crates/fj-core/src/algorithms/approx/half_edge.rs b/crates/fj-core/src/algorithms/approx/half_edge.rs
index 8cf23fc69..8c83c0e41 100644
--- a/crates/fj-core/src/algorithms/approx/half_edge.rs
+++ b/crates/fj-core/src/algorithms/approx/half_edge.rs
@@ -4,8 +4,10 @@
 
 use std::iter;
 
+use fj_math::Point;
+
 use crate::{
-    geometry::Geometry,
+    geometry::{CurveBoundary, Geometry},
     storage::Handle,
     topology::{HalfEdge, Surface},
 };
@@ -20,13 +22,13 @@ use super::{
 pub fn approx_half_edge(
     half_edge: &Handle<HalfEdge>,
     surface: &Handle<Surface>,
+    boundary: CurveBoundary<Point<1>>,
     tolerance: impl Into<Tolerance>,
     cache: &mut HalfEdgeApproxCache,
     geometry: &Geometry,
 ) -> HalfEdgeApprox {
     let tolerance = tolerance.into();
 
-    let boundary = geometry.of_half_edge(half_edge).boundary;
     let [start_position_curve, _] = boundary.inner;
 
     let start = approx_vertex(