diff --git a/crates/engine/src/cmd/inspect.rs b/crates/engine/src/cmd/inspect.rs
index d972caed..ed7b8abd 100644
--- a/crates/engine/src/cmd/inspect.rs
+++ b/crates/engine/src/cmd/inspect.rs
@@ -13,7 +13,7 @@ pub static COMMANDS: &[CommandSpec] = &[
         .icon("measure")
         .key("I")
         .noundo()
-        .params("bodies?: [names] (default all)"),
+        .params("bodies?: [names] (default all); or items: [1-2 selections] → length/area/volume, minimum distance (from, to) and angle"),
     CommandSpec::new("document.inspect", "Inspect Design", inspect).noundo().params("measure?: bool (include body measurements)"),
     CommandSpec::new("sketch.inspect", "Inspect Sketch", sketch_inspect).noundo().params("sketch?: id|name (default active)"),
     CommandSpec::new("model.edges", "List Edges", model_edges).noundo().params("body: name"),
@@ -46,6 +46,9 @@ pub fn measure_json(b: &solvecraft_doc::ModelBody) -> Value {
 }
 
 fn measure(s: &mut Session, p: &Value) -> Result<Value> {
+    if let Some(items) = p.get("items") {
+        return super::measure_sel::measure_items(s, items);
+    }
     let want = string_list(p, "bodies");
     let st = s.world_state();
     let mut bodies: Vec<Value> = st.bodies.iter().filter(|b| want.is_empty() || want.contains(&b.name)).map(measure_json).collect();
diff --git a/crates/engine/src/cmd/measure_sel.rs b/crates/engine/src/cmd/measure_sel.rs
new file mode 100644
index 00000000..c4c9e5a4
--- /dev/null
+++ b/crates/engine/src/cmd/measure_sel.rs
@@ -0,0 +1,177 @@
+//! Measuring picked geometry (`MeasureCommand` with `items`): one item gives its length, area,
+//! volume or position; two give the minimum distance between them (with the two closest
+//! points) and, where both have a direction (planar faces, straight edges), the angle.
+
+use serde_json::{Value, json};
+use solvecraft_geom::{Mesh, Vec3};
+
+use crate::params::bad;
+use crate::{Result, Sel, Session};
+
+/// Geometry of a picked item, as points or triangles.
+enum Geo {
+    Points(Vec<Vec3>),
+    Tris(Vec<[Vec3; 3]>),
+}
+
+/// Caps that keep a measurement interactive on big meshes.
+const MAX_POINTS: usize = 4000;
+const MAX_TRIS: usize = 20000;
+
+fn closest_on_triangle(p: Vec3, a: Vec3, b: Vec3, c: Vec3) -> Vec3 {
+    let n = (b - a).cross(c - a);
+    if let Some(nn) = n.normalized() {
+        let q = p - nn * (p - a).dot(nn);
+        if [(a, b), (b, c), (c, a)].iter().all(|(u, v)| (*v - *u).cross(q - *u).dot(n) >= -1e-12) {
+            return q;
+        }
+    }
+    let on_seg = |u: Vec3, v: Vec3| {
+        let d = v - u;
+        let l2 = d.dot(d);
+        let t = if l2 > 0.0 { ((p - u).dot(d) / l2).clamp(0.0, 1.0) } else { 0.0 };
+        u + d * t
+    };
+    [on_seg(a, b), on_seg(b, c), on_seg(c, a)].into_iter().min_by(|x, y| x.dist(p).total_cmp(&y.dist(p))).unwrap_or(a)
+}
+
+fn polyline_len(pts: &[Vec3]) -> f64 {
+    pts.windows(2).map(|w| w[0].dist(w[1])).sum()
+}
+
+/// A polyline with extra points so no gap is longer than 1/64 of it.
+fn densify(pts: &[Vec3]) -> Vec<Vec3> {
+    let step = (polyline_len(pts) / 64.0).max(1e-9);
+    let mut out = Vec::new();
+    for w in pts.windows(2) {
+        let n = ((w[0].dist(w[1]) / step).ceil() as usize).clamp(1, 64);
+        for k in 0..n {
+            out.push(w[0].lerp(w[1], k as f64 / n as f64));
+        }
+    }
+    out.extend(pts.last().copied());
+    out
+}
+
+/// The mesh edge a selection means: by index if it still passes through the point, otherwise
+/// the nearest.
+fn edge_points(m: &Mesh, index: usize, point: Vec3) -> Option<Vec<Vec3>> {
+    let near = |e: &Vec<Vec3>| e.windows(2).map(|w| point.dist_to_segment(w[0], w[1])).fold(f64::INFINITY, f64::min);
+    let tol = m.bounds().diagonal().max(1.0) * 1e-6;
+    if let Some(e) = m.edges.get(index).filter(|e| near(e) < tol) {
+        return Some(e.clone());
+    }
+    m.edges.iter().min_by(|a, b| near(a).total_cmp(&near(b))).cloned()
+}
+
+fn face_tris(m: &Mesh, f: usize) -> Vec<[Vec3; 3]> {
+    m.triangles.iter().zip(&m.tri_face).filter(|(_, tf)| **tf as usize == f).filter_map(|(t, _)| m.tri(t)).collect()
+}
+
+/// Geometry, direction (planar face normal, straight edge direction) and a description.
+fn describe(s: &Session, sel: &Sel) -> Option<(Geo, Option<Vec3>, Value)> {
+    let st = s.world_state();
+    Some(match sel {
+        Sel::Vertex { point, .. } => (Geo::Points(vec![*point]), None, json!({"type": "vertex", "position": point})),
+        Sel::Edge { body, index, point } => {
+            let m = st.body(body)?.mesh();
+            let pts = edge_points(&m, *index, *point)?;
+            let (a, b) = (*pts.first()?, *pts.last()?);
+            let straight = (b - a).normalized().filter(|d| pts.iter().all(|p| (*p - a).cross(*d).len() < 1e-6 * (1.0 + a.dist(b))));
+            let len = polyline_len(&pts);
+            (Geo::Points(densify(&pts)), straight, json!({"type": "edge", "length_mm": len}))
+        }
+        Sel::Face { body, index, .. } => {
+            let m = st.body(body)?.mesh();
+            let tris = face_tris(&m, *index);
+            let area: f64 = tris.iter().map(|[a, b, c]| (*b - *a).cross(*c - *a).len() * 0.5).sum();
+            let normals: Vec<Vec3> = tris.iter().filter_map(|[a, b, c]| (*b - *a).cross(*c - *a).normalized()).collect();
+            let planar = normals.first().copied().filter(|n0| normals.iter().all(|n| n.dot(*n0) > 1.0 - 1e-6));
+            (Geo::Tris(tris), planar, json!({"type": "face", "area_mm2": area, "planar": planar.is_some()}))
+        }
+        Sel::Body { name } => {
+            let m = st.body(name)?.mesh();
+            let tris: Vec<[Vec3; 3]> = m.triangles.iter().filter_map(|t| m.tri(t)).collect();
+            let v = m.measure().volume;
+            (Geo::Tris(tris), None, json!({"type": "body", "name": name, "volume_mm3": v}))
+        }
+        _ => return None,
+    })
+}
+
+fn sample<T: Copy>(v: &[T], max: usize) -> Vec<T> {
+    let step = v.len().div_ceil(max).max(1);
+    v.iter().step_by(step).copied().collect()
+}
+
+/// Closest pair of points between two pieces of geometry.
+fn closest(a: &Geo, b: &Geo) -> Option<(Vec3, Vec3)> {
+    let pts_to_tris = |pts: &[Vec3], tris: &[[Vec3; 3]]| -> Option<(Vec3, Vec3)> {
+        let pts = sample(pts, MAX_POINTS);
+        let tris = sample(tris, MAX_TRIS);
+        let mut best: Option<(f64, Vec3, Vec3)> = None;
+        for p in &pts {
+            for [x, y, z] in &tris {
+                let q = closest_on_triangle(*p, *x, *y, *z);
+                let d = p.dist(q);
+                if best.is_none_or(|(bd, _, _)| d < bd) {
+                    best = Some((d, *p, q));
+                }
+            }
+        }
+        best.map(|(_, p, q)| (p, q))
+    };
+    let verts = |tris: &[[Vec3; 3]]| -> Vec<Vec3> { tris.iter().flat_map(|t| t.iter().copied()).collect() };
+    match (a, b) {
+        (Geo::Points(p), Geo::Points(q)) => {
+            let (p, q) = (sample(p, MAX_POINTS), sample(q, MAX_POINTS));
+            let mut best: Option<(f64, Vec3, Vec3)> = None;
+            for x in &p {
+                for y in &q {
+                    let d = x.dist(*y);
+                    if best.is_none_or(|(bd, _, _)| d < bd) {
+                        best = Some((d, *x, *y));
+                    }
+                }
+            }
+            best.map(|(_, x, y)| (x, y))
+        }
+        (Geo::Points(p), Geo::Tris(t)) => pts_to_tris(p, t),
+        (Geo::Tris(t), Geo::Points(p)) => pts_to_tris(p, t).map(|(x, y)| (y, x)),
+        (Geo::Tris(t1), Geo::Tris(t2)) => {
+            let ab = pts_to_tris(&verts(t1), t2);
+            let ba = pts_to_tris(&verts(t2), t1).map(|(x, y)| (y, x));
+            [ab, ba].into_iter().flatten().min_by(|x, y| x.0.dist(x.1).total_cmp(&y.0.dist(y.1)))
+        }
+    }
+}
+
+/// `MeasureCommand` with `items` (one or two selections).
+pub(crate) fn measure_items(s: &Session, items: &Value) -> Result<Value> {
+    let cmd = "MeasureCommand";
+    let list = items.as_array().ok_or_else(|| bad(cmd, "`items` must be a list of selections"))?;
+    if list.is_empty() || list.len() > 2 {
+        return Err(bad(cmd, "measure one or two items"));
+    }
+    let sels: Vec<Sel> = list.iter().map(|v| serde_json::from_value::<Sel>(v.clone()).map_err(|e| bad(cmd, e.to_string()))).collect::<Result<_>>()?;
+    let mut described = Vec::new();
+    for x in &sels {
+        described.push(describe(s, x).ok_or_else(|| bad(cmd, "an item can't be measured (pick vertices, edges, faces or bodies)"))?);
+    }
+    let mut out = json!({"items": described.iter().map(|d| d.2.clone()).collect::<Vec<_>>()});
+    if let [(ga, da, _), (gb, db, _)] = described.as_slice() {
+        if let Some((p, q)) = closest(ga, gb) {
+            out["distance_mm"] = json!(p.dist(q));
+            out["from"] = json!(p);
+            out["to"] = json!(q);
+            out["delta"] = json!(q - p);
+        }
+        if let (Some(a), Some(b)) = (da, db) {
+            let both_faces = matches!(sels.as_slice(), [Sel::Face { .. }, Sel::Face { .. }]);
+            let c = a.dot(*b).clamp(-1.0, 1.0);
+            let c = if both_faces { c } else { c.abs() };
+            out["angle_deg"] = json!(c.acos().to_degrees());
+        }
+    }
+    Ok(out)
+}
diff --git a/crates/engine/src/cmd/mod.rs b/crates/engine/src/cmd/mod.rs
index a93d8be3..54b97cd0 100644
--- a/crates/engine/src/cmd/mod.rs
+++ b/crates/engine/src/cmd/mod.rs
@@ -9,6 +9,8 @@ mod features;
 pub use features::auto_operation;
 mod file;
 mod inspect;
+mod measure_sel;
+pub(crate) use measure_sel::measure_items;
 mod sketch;
 mod sketch_constraints;
 mod sketch_create;
diff --git a/crates/engine/src/lib.rs b/crates/engine/src/lib.rs
index 9d847056..f349dee4 100644
--- a/crates/engine/src/lib.rs
+++ b/crates/engine/src/lib.rs
@@ -342,6 +342,13 @@ impl Session {
         Ok(self.model.state())
     }
 
+    /// Measure one or two selections (see `MeasureCommand` with `items`); errors come back as
+    /// `{"error": …}`.
+    pub fn measure_items(&self, items: &[Sel]) -> Value {
+        let v = serde_json::to_value(items).unwrap_or(Value::Null);
+        cmd::measure_items(self, &v).unwrap_or_else(|e| serde_json::json!({ "error": e.to_string() }))
+    }
+
     /// Run a script: a JSON array of `{"command": id, "params": {...}}` (or an object with a
     /// `commands` array). Stops at the first error. Returns each command's result.
     pub fn run_script(&mut self, script: &Value) -> Result<Vec<Value>> {
diff --git a/crates/engine/src/tests.rs b/crates/engine/src/tests.rs
index 3e192729..4b0cc50a 100644
--- a/crates/engine/src/tests.rs
+++ b/crates/engine/src/tests.rs
@@ -582,6 +582,40 @@ fn extrude_auto_operation() {
     assert!(rel(volume(&mut s), 40.0 * 30.0 * 15.0 - 100.0 * 8.0) < 1e-6);
 }
 
+/// Measuring picked geometry: distance between faces, angle, edge length.
+#[test]
+fn measure_items() {
+    let mut s = Session::default();
+    run(&mut s, "PrimitiveBox", json!({"length": 40, "width": 30, "height": 20}));
+    let st = s.model.state();
+    let m = st.body("Body1").unwrap().mesh();
+    // Find the faces by their centroid: top (z = 20), bottom (z = 0), front (y = 0).
+    let face_at = |z: Option<f64>, y: Option<f64>| -> usize {
+        (0..6)
+            .find(|f| {
+                let tris: Vec<_> = m.triangles.iter().zip(&m.tri_face).filter(|(_, tf)| **tf as usize == *f).filter_map(|(t, _)| m.tri(t)).collect();
+                tris.iter().all(|t| t.iter().all(|p| z.is_none_or(|z| (p.z - z).abs() < 1e-9) && y.is_none_or(|y| (p.y - y).abs() < 1e-9)))
+            })
+            .unwrap()
+    };
+    let (ft, fb, ff) = (face_at(Some(20.0), None), face_at(Some(0.0), None), face_at(None, Some(0.0)));
+    let face = |i: usize, p: [f64; 3]| json!({"type": "face", "body": "Body1", "index": i, "point": p});
+    let r = run(&mut s, "MeasureCommand", json!({"items": [face(ft, [20.0, 15.0, 20.0]), face(fb, [20.0, 15.0, 0.0])]}));
+    assert!((r["distance_mm"].as_f64().unwrap() - 20.0).abs() < 1e-9, "{r}");
+    assert!((r["angle_deg"].as_f64().unwrap() - 180.0).abs() < 1e-6, "{r}");
+    let r = run(&mut s, "MeasureCommand", json!({"items": [face(ft, [20.0, 15.0, 20.0]), face(ff, [20.0, 0.0, 10.0])]}));
+    assert!(r["distance_mm"].as_f64().unwrap() < 1e-9);
+    assert!((r["angle_deg"].as_f64().unwrap() - 90.0).abs() < 1e-6);
+    let r = run(&mut s, "MeasureCommand", json!({"items": [face(ft, [20.0, 15.0, 20.0])]}));
+    assert!((r["items"][0]["area_mm2"].as_f64().unwrap() - 1200.0).abs() < 1e-6, "{r}");
+    let v = json!({"type": "vertex", "body": "Body1", "point": [0, 0, 0]});
+    let w = json!({"type": "vertex", "body": "Body1", "point": [40, 30, 20]});
+    let r = run(&mut s, "MeasureCommand", json!({"items": [v, w]}));
+    assert!((r["distance_mm"].as_f64().unwrap() - (1600.0f64 + 900.0 + 400.0).sqrt()).abs() < 1e-9);
+    assert!(s.execute("MeasureCommand", &json!({"items": []})).is_err());
+    assert!(s.execute("MeasureCommand", &json!({"items": [{"type": "nonsense"}]})).is_err());
+}
+
 /// Press Pull: positive pulls a face out, negative pushes it in (a cut), edges get a fillet.
 #[test]
 fn press_pull() {
diff --git a/crates/ui-egui/src/canvas.rs b/crates/ui-egui/src/canvas.rs
index 59d6be62..a3ee765e 100644
--- a/crates/ui-egui/src/canvas.rs
+++ b/crates/ui-egui/src/canvas.rs
@@ -64,6 +64,11 @@ fn edge_bisector(m: &Mesh, index: usize, p: Vec3) -> Option<Vec3> {
 /// Draw the manipulator and the value box (called by the viewport after the model is drawn).
 pub fn show(app: &mut SolveApp, ui: &mut egui::Ui, painter: &egui::Painter, proj: &Proj) {
     let Some(mut d) = app.dialog.take() else { return };
+    if let Kind::Measure { result: Some(r), .. } = &d.kind {
+        measure_line(painter, proj, r);
+        app.dialog = Some(d);
+        return;
+    }
     if let Some((base, dir)) = anchor(app, &d)
         && let Some(bs) = proj.to_screen(base)
     {
@@ -202,6 +207,26 @@ fn drag_arrow(
     Some(ts)
 }
 
+/// The measured distance: a line between the closest points with its length.
+fn measure_line(painter: &egui::Painter, proj: &Proj, r: &serde_json::Value) {
+    let t = Tokens::get();
+    let p = |k: &str| -> Option<Vec3> {
+        let a = r.get(k)?.as_array()?;
+        Some(Vec3::new(a.first()?.as_f64()?, a.get(1)?.as_f64()?, a.get(2)?.as_f64()?))
+    };
+    let (Some(a), Some(b), Some(d)) = (p("from"), p("to"), r.get("distance_mm").and_then(|v| v.as_f64())) else { return };
+    let (Some(sa), Some(sb)) = (proj.to_screen(a), proj.to_screen(b)) else { return };
+    painter.line_segment([sa, sb], Stroke::new(2.0, t.manipulator));
+    for s in [sa, sb] {
+        painter.circle(s, 3.5, t.manipulator, Stroke::new(1.0, Color32::WHITE));
+    }
+    let mid = sa + (sb - sa) * 0.5 + vec2(10.0, -14.0);
+    let galley = painter.layout_no_wrap(format!("{d:.3} mm"), egui::FontId::proportional(12.5), t.text);
+    let rect = egui::Rect::from_min_size(mid, galley.size() + vec2(10.0, 6.0));
+    painter.rect(rect, 3.0, t.overlay, Stroke::new(1.0, t.border), egui::StrokeKind::Inside);
+    painter.galley(rect.min + vec2(5.0, 3.0), galley, t.text);
+}
+
 /// The revolve axis (a point on it and its unit direction).
 fn revolve_axis(app: &SolveApp, d: &Dialog) -> Option<(Vec3, Vec3)> {
     if !matches!(d.kind, Kind::Revolve { .. }) {
diff --git a/crates/ui-egui/src/dialogs.rs b/crates/ui-egui/src/dialogs.rs
index 87b15d7c..196b82ad 100644
--- a/crates/ui-egui/src/dialogs.rs
+++ b/crates/ui-egui/src/dialogs.rs
@@ -78,6 +78,12 @@ pub enum Kind {
     Sweep {
         operation: usize,
     },
+    /// Measure one or two picked items (vertices, edges, faces): the result of the last
+    /// measurement and the items it was for.
+    Measure {
+        result: Option<Value>,
+        of: Vec<Sel>,
+    },
     /// Move bodies by a distance along X, Y and Z.
     Move {
         x: String,
@@ -191,6 +197,9 @@ impl Dialog {
             "MirrorCommand" => {
                 Dialog::new(Kind::Mirror, vec![SelInput::new("Bodies", BODIES, true), SelInput::new("Mirror plane", PLANES | PLANAR_FACES, false)])
             }
+            "MeasureCommand" => {
+                Dialog::new(Kind::Measure { result: None, of: Vec::new() }, vec![SelInput::new("Items", FACES | EDGES | selection::VERTICES, true)])
+            }
             "PatternRectangular" => Dialog::new(
                 Kind::PatternRect { count: "3".into(), spacing: "20 mm".into(), count2: "1".into(), spacing2: "20 mm".into() },
                 vec![SelInput::new("Objects", BODIES, true), SelInput::new("Direction", AXES, false), SelInput::new("Direction 2", AXES, false)],
@@ -373,6 +382,11 @@ impl Dialog {
         let Some(inp) = self.inputs.get_mut(self.active) else { return };
         inp.toggle(picked);
         self.focus = true;
+        // A measurement is between two items: a third pick starts over from the last one.
+        if matches!(self.kind, Kind::Measure { .. }) && inp.items.len() > 2 {
+            let keep = inp.items.split_off(inp.items.len() - 1);
+            inp.items = keep;
+        }
         if !inp.multi && !inp.items.is_empty() && self.active + 1 < self.inputs.len() {
             self.advance();
         }
@@ -465,6 +479,7 @@ fn title(k: &Kind) -> &'static str {
         Kind::Shell { .. } => "SHELL",
         Kind::Draft { .. } => "DRAFT",
         Kind::Mirror => "MIRROR",
+        Kind::Measure { .. } => "MEASURE",
         Kind::PatternRect { .. } => "RECTANGULAR PATTERN",
         Kind::PatternCirc { .. } => "CIRCULAR PATTERN",
         Kind::Loft { .. } => "LOFT",
@@ -550,6 +565,68 @@ const DIALOG_MAX_W: f32 = 380.0;
 /// Width of value fields and choice boxes in a dialog.
 const FIELD_W: f32 = 140.0;
 
+/// Measure again when the picked items changed.
+fn update_measure(app: &SolveApp, d: &mut Dialog) {
+    let items: Vec<Sel> = sels(d, 0).to_vec();
+    if let Kind::Measure { result, of } = &mut d.kind
+        && *of != items
+    {
+        *result = if items.is_empty() { None } else { Some(app.session.measure_items(&items)) };
+        *of = items;
+    }
+}
+
+fn fmt_mm(v: &Value) -> String {
+    v.as_f64().map(|x| format!("{x:.3} mm")).unwrap_or_default()
+}
+
+/// The measurement in the dialog.
+fn measure_rows(ui: &mut egui::Ui, r: Option<&Value>) {
+    let t = Tokens::get();
+    let Some(r) = r else {
+        ui.label("");
+        ui.label(RichText::new("pick one or two vertices, edges or faces").color(t.text_dim));
+        ui.end_row();
+        return;
+    };
+    if let Some(e) = r.get("error").and_then(Value::as_str) {
+        ui.label("");
+        ui.label(RichText::new(e).color(t.error));
+        ui.end_row();
+        return;
+    }
+    for (i, it) in r["items"].as_array().into_iter().flatten().enumerate() {
+        let what = match it["type"].as_str() {
+            Some("edge") => format!("Length  {}", fmt_mm(&it["length_mm"])),
+            Some("face") => format!("Area  {:.3} mm²", it["area_mm2"].as_f64().unwrap_or(0.0)),
+            Some("vertex") => {
+                let p = &it["position"];
+                format!("At  {:.3}, {:.3}, {:.3}", p[0].as_f64().unwrap_or(0.0), p[1].as_f64().unwrap_or(0.0), p[2].as_f64().unwrap_or(0.0))
+            }
+            _ => String::new(),
+        };
+        ui.label(format!("Item {}", i + 1));
+        ui.label(what);
+        ui.end_row();
+    }
+    if r.get("distance_mm").is_some() {
+        ui.label(RichText::new("Distance").strong());
+        ui.label(RichText::new(fmt_mm(&r["distance_mm"])).strong());
+        ui.end_row();
+        let d = &r["delta"];
+        for (k, l) in ["ΔX", "ΔY", "ΔZ"].iter().enumerate() {
+            ui.label(*l);
+            ui.label(format!("{:.3} mm", d[k].as_f64().unwrap_or(0.0).abs()));
+            ui.end_row();
+        }
+    }
+    if let Some(a) = r["angle_deg"].as_f64() {
+        ui.label(RichText::new("Angle").strong());
+        ui.label(RichText::new(format!("{a:.3}°")).strong());
+        ui.end_row();
+    }
+}
+
 /// Keep an automatic extrude operation in step with the geometry.
 fn auto_operation(app: &SolveApp, d: &mut Dialog) {
     if !matches!(d.kind, Kind::Extrude { auto_op: true, .. }) {
@@ -572,6 +649,7 @@ fn auto_operation(app: &SolveApp, d: &mut Dialog) {
 pub fn show(app: &mut SolveApp, ctx: &egui::Context) {
     let Some(mut d) = app.dialog.take() else { return };
     auto_operation(app, &mut d);
+    update_measure(app, &mut d);
     let t = Tokens::get();
     let vp = app.viewport.rect.unwrap_or_else(|| ctx.content_rect());
     let anchor = egui::pos2(vp.right(), vp.top() + crate::viewport::VIEW_CUBE_CLEARANCE);
@@ -660,6 +738,7 @@ pub fn show(app: &mut SolveApp, ctx: &egui::Context) {
                         ui.end_row();
                     }
                     Kind::Mirror => {}
+                    Kind::Measure { result, .. } => measure_rows(ui, result.as_ref()),
                     Kind::PatternRect { count, spacing, count2, spacing2 } => {
                         for (l, v) in [("Quantity", count), ("Spacing", spacing), ("Quantity 2", count2), ("Spacing 2", spacing2)] {
                             ui.label(l);
@@ -779,7 +858,7 @@ pub fn show(app: &mut SolveApp, ctx: &egui::Context) {
             });
             ui.add_space(6.0);
             ui.horizontal(|ui| {
-                if !matches!(d.kind, Kind::Sketch | Kind::Params { .. })
+                if !matches!(d.kind, Kind::Sketch | Kind::Params { .. } | Kind::Measure { .. })
                     && ui
                         .add(
                             egui::Button::new(
@@ -792,7 +871,7 @@ pub fn show(app: &mut SolveApp, ctx: &egui::Context) {
                 {
                     ok = true;
                 }
-                let close = if matches!(d.kind, Kind::Params { .. }) { "Close" } else { "Cancel" };
+                let close = if matches!(d.kind, Kind::Params { .. } | Kind::Measure { .. }) { "Close" } else { "Cancel" };
                 if ui.add(egui::Button::new(close).min_size(vec2(70.0, 24.0))).clicked() {
                     cancel = true;
                 }
@@ -1165,7 +1244,7 @@ fn dialog_commands(app: &SolveApp, d: &Dialog) -> Result<Vec<(String, Value)>, S
         Kind::EditParam { name, expr } => ("ChangeParameterCommand", json!({"name": name, "expression": expr})),
         Kind::Rename { feature, name } => ("FusionRenameTimelineEntryCommand", json!({"feature": feature, "name": name})),
         Kind::ConfirmDelete { feature, .. } => ("FusionDeleteCommand", json!({ "features": [feature.to_string()] })),
-        Kind::Sketch | Kind::Params { .. } => return Ok(Vec::new()),
+        Kind::Sketch | Kind::Params { .. } | Kind::Measure { .. } => return Ok(Vec::new()),
     };
     let mut params = params;
     if let Value::Object(m) = &mut params {
@@ -1302,7 +1381,10 @@ fn op_index(o: &Operation) -> usize {
 
 /// The origin axis a unit direction runs along (either way), if any.
 fn world_axis(d: Vec3) -> Option<String> {
-    [("X", Vec3::X), ("Y", Vec3::Y), ("Z", Vec3::Z)].into_iter().find(|(_, a)| d.cross(*a).len() < 1e-9 && d.dot(*a) > 0.0).map(|(n, _)| n.to_string())
+    [("X", Vec3::X), ("Y", Vec3::Y), ("Z", Vec3::Z)]
+        .into_iter()
+        .find(|(_, a)| d.cross(*a).len() < 1e-9 && d.dot(*a) > 0.0)
+        .map(|(n, _)| n.to_string())
 }
 
 fn pt3(v: Vec3) -> Value {
diff --git a/crates/ui-egui/src/viewport.rs b/crates/ui-egui/src/viewport.rs
index 07170c8a..35a41062 100644
--- a/crates/ui-egui/src/viewport.rs
+++ b/crates/ui-egui/src/viewport.rs
@@ -152,7 +152,7 @@ fn scene_key(app: &SolveApp) -> u64 {
     app.ui.show_sketches.hash(&mut h);
     app.ui.hidden_bodies.hash(&mut h);
     app.preview.replaced.hash(&mut h);
-    app.ui.dark.hash(&mut h);
+    crate::theme::is_dark().hash(&mut h);
     app.session.active_sketch.hash(&mut h);
     let (minor, _) = grid_step(app.cam.half_height());
     minor.to_bits().hash(&mut h);
@@ -535,7 +535,7 @@ fn highlight_key(app: &SolveApp) -> u64 {
     serde_json::to_string(&app.highlighted()).unwrap_or_default().hash(&mut h);
     format!("{:?}", app.viewport.hover).hash(&mut h);
     app.viewport.hover_feature.hash(&mut h);
-    app.ui.dark.hash(&mut h);
+    crate::theme::is_dark().hash(&mut h);
     app.preview.replaced.hash(&mut h);
     app.origin_visible().hash(&mut h);
     app.ui.hidden_origin.hash(&mut h);