diff --git a/crates/fj-core/src/geometry/util/mod.rs b/crates/fj-core/src/geometry/util/mod.rs
index 1bc0744df..b5fc9803f 100644
--- a/crates/fj-core/src/geometry/util/mod.rs
+++ b/crates/fj-core/src/geometry/util/mod.rs
@@ -7,38 +7,4 @@
 //! module provides an easy place to put new things, before it's clear what to
 //! do with them long-term.
 
-use fj_math::{Aabb, Point};
-
-use super::{traits::GenPolyline, CurveBoundary, Tolerance};
-
-/// # Convert a point on a curve from curve coordinates to surface coordinates
-pub fn curve_point_to_surface_point(
-    curve: &dyn GenPolyline<2>,
-    point_curve: impl Into<Point<1>>,
-    tolerance: impl Into<Tolerance>,
-) -> Point<2> {
-    let point_curve = point_curve.into();
-    let tolerance = tolerance.into();
-
-    let line_segment = curve.line_segment_at(point_curve, tolerance);
-    let line = line_segment.to_line();
-
-    line.point_from_line_coords(point_curve)
-}
-
-/// # Generate a 2D axis-aligned bounding box for a curve in a given range
-pub fn surface_aabb_from_bounded_curve(
-    curve: &dyn GenPolyline<2>,
-    boundary: impl Into<CurveBoundary<Point<1>>>,
-    tolerance: impl Into<Tolerance>,
-) -> Aabb<2> {
-    let boundary = boundary.into();
-    let tolerance = tolerance.into();
-
-    let points_curve = curve.generate_polyline(boundary, tolerance);
-    let points_surface = points_curve.into_iter().map(|point_curve| {
-        curve_point_to_surface_point(curve, point_curve, tolerance)
-    });
-
-    Aabb::<2>::from_points(points_surface)
-}
+pub mod polyline;
diff --git a/crates/fj-core/src/geometry/util/polyline.rs b/crates/fj-core/src/geometry/util/polyline.rs
new file mode 100644
index 000000000..615d3df06
--- /dev/null
+++ b/crates/fj-core/src/geometry/util/polyline.rs
@@ -0,0 +1,37 @@
+//! # Geometric utility code based on polylines
+
+use fj_math::{Aabb, Point};
+
+use crate::geometry::{traits::GenPolyline, CurveBoundary, Tolerance};
+
+/// # Convert a point on a curve from curve coordinates to surface coordinates
+pub fn curve_point_to_surface_point(
+    curve: &dyn GenPolyline<2>,
+    point_curve: impl Into<Point<1>>,
+    tolerance: impl Into<Tolerance>,
+) -> Point<2> {
+    let point_curve = point_curve.into();
+    let tolerance = tolerance.into();
+
+    let line_segment = curve.line_segment_at(point_curve, tolerance);
+    let line = line_segment.to_line();
+
+    line.point_from_line_coords(point_curve)
+}
+
+/// # Generate a 2D axis-aligned bounding box for a curve in a given range
+pub fn surface_aabb_from_bounded_curve(
+    curve: &dyn GenPolyline<2>,
+    boundary: impl Into<CurveBoundary<Point<1>>>,
+    tolerance: impl Into<Tolerance>,
+) -> Aabb<2> {
+    let boundary = boundary.into();
+    let tolerance = tolerance.into();
+
+    let points_curve = curve.generate_polyline(boundary, tolerance);
+    let points_surface = points_curve.into_iter().map(|point_curve| {
+        curve_point_to_surface_point(curve, point_curve, tolerance)
+    });
+
+    Aabb::<2>::from_points(points_surface)
+}