diff --git a/crates/fj-kernel/src/algorithms/intersection/surface_surface.rs b/crates/fj-kernel/src/algorithms/intersection/surface_surface.rs
index 430da8ea7..5b771d384 100644
--- a/crates/fj-kernel/src/algorithms/intersection/surface_surface.rs
+++ b/crates/fj-kernel/src/algorithms/intersection/surface_surface.rs
@@ -101,7 +101,6 @@ fn project_line_into_plane(
     plane: &PlaneParametric,
 ) -> Curve<2> {
     let line_origin_relative_to_plane = line.origin - plane.origin;
-    dbg!(&line_origin_relative_to_plane);
     let line_origin_in_plane = Vector::from([
         plane
             .u
diff --git a/crates/fj-kernel/src/algorithms/transform.rs b/crates/fj-kernel/src/algorithms/transform.rs
index 13ea5da38..af3e6f2b3 100644
--- a/crates/fj-kernel/src/algorithms/transform.rs
+++ b/crates/fj-kernel/src/algorithms/transform.rs
@@ -110,16 +110,20 @@ impl TransformObject for GlobalVertex {
 
 impl TransformObject for Sketch {
     fn transform(self, transform: &Transform) -> Self {
-        let mut faces = self.into_faces();
-        transform_faces(&mut faces, transform);
+        let faces = self
+            .into_faces()
+            .into_iter()
+            .map(|face| face.transform(transform));
         Self::from_faces(faces)
     }
 }
 
 impl TransformObject for Solid {
     fn transform(self, transform: &Transform) -> Self {
-        let mut faces = self.into_faces();
-        transform_faces(&mut faces, transform);
+        let faces = self
+            .into_faces()
+            .into_iter()
+            .map(|face| face.transform(transform));
         Self::from_faces(faces)
     }
 }
diff --git a/crates/fj-kernel/src/objects/sketch.rs b/crates/fj-kernel/src/objects/sketch.rs
index 1cf200407..69a4f7411 100644
--- a/crates/fj-kernel/src/objects/sketch.rs
+++ b/crates/fj-kernel/src/objects/sketch.rs
@@ -1,3 +1,5 @@
+use std::collections::BTreeSet;
+
 use super::Face;
 
 /// A 2-dimensional shape
@@ -8,7 +10,7 @@ use super::Face;
 /// currently validated.
 #[derive(Clone, Debug, Eq, PartialEq, Hash, Ord, PartialOrd)]
 pub struct Sketch {
-    faces: Vec<Face>,
+    faces: BTreeSet<Face>,
 }
 
 impl Sketch {
@@ -24,7 +26,7 @@ impl Sketch {
     }
 
     /// Convert the sketch into a list of faces
-    pub fn into_faces(self) -> Vec<Face> {
+    pub fn into_faces(self) -> BTreeSet<Face> {
         self.faces
     }
 }
diff --git a/crates/fj-kernel/src/objects/solid.rs b/crates/fj-kernel/src/objects/solid.rs
index a2ce1f0e5..65c53533c 100644
--- a/crates/fj-kernel/src/objects/solid.rs
+++ b/crates/fj-kernel/src/objects/solid.rs
@@ -1,3 +1,5 @@
+use std::collections::BTreeSet;
+
 use fj_math::Scalar;
 
 use crate::algorithms::TransformObject;
@@ -12,7 +14,7 @@ use super::{Face, Surface};
 /// currently validated.
 #[derive(Clone, Debug, Eq, PartialEq, Hash, Ord, PartialOrd)]
 pub struct Solid {
-    faces: Vec<Face>,
+    faces: BTreeSet<Face>,
 }
 
 impl Solid {
@@ -53,7 +55,7 @@ impl Solid {
     }
 
     /// Convert the solid into a list of faces
-    pub fn into_faces(self) -> Vec<Face> {
+    pub fn into_faces(self) -> BTreeSet<Face> {
         self.faces
     }
 }
diff --git a/crates/fj-operations/src/lib.rs b/crates/fj-operations/src/lib.rs
index be66802ee..3efb51e72 100644
--- a/crates/fj-operations/src/lib.rs
+++ b/crates/fj-operations/src/lib.rs
@@ -66,7 +66,9 @@ impl Shape for fj::Shape {
                 shape
                     .compute_brep(config, tolerance, debug_info)?
                     .into_inner()
-                    .into_faces(),
+                    .into_faces()
+                    .into_iter()
+                    .collect(),
                 config,
             ),
             Self::Group(shape) => {
@@ -76,7 +78,9 @@ impl Shape for fj::Shape {
                 shape
                     .compute_brep(config, tolerance, debug_info)?
                     .into_inner()
-                    .into_faces(),
+                    .into_faces()
+                    .into_iter()
+                    .collect(),
                 config,
             ),
             Self::Transform(shape) => {