diff --git a/crates/fj-core/src/operations/build/sketch.rs b/crates/fj-core/src/operations/build/sketch.rs
index 01d5cf2a5..b21a2c70d 100644
--- a/crates/fj-core/src/operations/build/sketch.rs
+++ b/crates/fj-core/src/operations/build/sketch.rs
@@ -1,4 +1,4 @@
-use crate::topology::Sketch;
+use crate::topology::{Sketch, Topology};
 
 /// Build a [`Sketch`]
 ///
@@ -7,7 +7,7 @@ use crate::topology::Sketch;
 /// [module-level documentation]: super
 pub trait BuildSketch {
     /// Create a sketch with no regions
-    fn empty() -> Sketch {
+    fn empty(_: &Topology) -> Sketch {
         Sketch::new([])
     }
 }
diff --git a/models/cuboid/src/lib.rs b/models/cuboid/src/lib.rs
index 6c37de589..e9df50729 100644
--- a/models/cuboid/src/lib.rs
+++ b/models/cuboid/src/lib.rs
@@ -16,7 +16,7 @@ pub fn model(size: impl Into<Vector<3>>, core: &mut fj::core::Core) -> Solid {
     let bottom_surface = core.layers.topology.surfaces.xy_plane();
     let sweep_path = Vector::from([Scalar::ZERO, Scalar::ZERO, z]);
 
-    Sketch::empty()
+    Sketch::empty(&core.layers.topology)
         .add_regions(
             [Region::polygon(
                 [
diff --git a/models/spacer/src/lib.rs b/models/spacer/src/lib.rs
index 89db21660..e214fcc2b 100644
--- a/models/spacer/src/lib.rs
+++ b/models/spacer/src/lib.rs
@@ -20,7 +20,7 @@ pub fn model(
     let bottom_surface = core.layers.topology.surfaces.xy_plane();
     let sweep_path = Vector::from([0., 0., height]);
 
-    Sketch::empty()
+    Sketch::empty(&core.layers.topology)
         .add_regions(
             [Region::circle(Point::origin(), outer, core).add_interiors(
                 [Cycle::circle(Point::origin(), inner, core).reverse(core)],
diff --git a/models/star/src/lib.rs b/models/star/src/lib.rs
index 35615b420..02b6ea537 100644
--- a/models/star/src/lib.rs
+++ b/models/star/src/lib.rs
@@ -43,7 +43,7 @@ pub fn model(
     let bottom_surface = core.layers.topology.surfaces.xy_plane();
     let sweep_path = Vector::from([0., 0., h]);
 
-    Sketch::empty()
+    Sketch::empty(&core.layers.topology)
         .add_regions(
             [Region::polygon(outer_points, core).add_interiors(
                 [Cycle::polygon(inner_points, core).reverse(core)],