diff --git a/crates/kernel/src/planar_sources.rs b/crates/kernel/src/planar_sources.rs
index af081a1f58..ad0ee3249c 100644
--- a/crates/kernel/src/planar_sources.rs
+++ b/crates/kernel/src/planar_sources.rs
@@ -141,6 +141,12 @@ impl Body {
         self.map_planar_sources(&[input], None, None, &[], false)
     }
 
+    /// Generate distinct outer/inner roles from the exact original supports of
+    /// an inside shell. Generated rims and curved walls are intentionally absent.
+    pub(crate) fn with_shell_planar_sources(self, input: &Body, thickness: f64, open: &[Vec3]) -> Result<Self> {
+        self.map_planar_sources(&[input], Some(thickness), None, open, false)
+    }
+
     /// Retain exact shell roles, and construction roles for Cut, only on unchanged
     /// supports without a competing coplanar tool. No imported or fitted role is inferred.
     pub(crate) fn with_preserved_boolean_planar_sources(self, input: &Body, tool: &Body, constructed: bool) -> Result<Self> {
diff --git a/crates/kernel/src/polyhedron.rs b/crates/kernel/src/polyhedron.rs
index 5b966f9cd4..4b895bce97 100644
--- a/crates/kernel/src/polyhedron.rs
+++ b/crates/kernel/src/polyhedron.rs
@@ -185,10 +185,12 @@ fn polyhedron_record(hs: &[HalfSpace], verts: &[Vec3], faces: &[(usize, Vec<usiz
 }
 
 /// Hollow a body: walls of `thickness` inside, open at the faces under `open` (SMLib's shell).
-/// The result's history is over `[b]`: the inner walls are offsets of the faces they line.
+/// The result's history is over `[b]`: the inner walls are offsets of the faces they line. Each
+/// kept planar wall and its inner lining carry the outer and inner shell roles of the face they
+/// came from (face certificates: sketches and press-pulls attach to them).
 pub fn shell(b: &Body, open: &[Vec3], thickness: f64) -> Result<Body> {
     let _span = solidcraft_profile::span("kernel", "shell");
-    crate::offset_backend::shell(b, open, thickness)
+    crate::offset_backend::shell(b, open, thickness)?.with_shell_planar_sources(b, thickness, open)
 }
 
 /// Tilt the faces near `faces` by `angle` about their line on the neutral plane, so that they