diff --git a/crates/engine/src/cmd/sketch.rs b/crates/engine/src/cmd/sketch.rs
index 11ad1a31..f26e5037 100644
--- a/crates/engine/src/cmd/sketch.rs
+++ b/crates/engine/src/cmd/sketch.rs
@@ -27,7 +27,7 @@ pub static COMMANDS: &[CommandSpec] = &[
         .icon("rect")
         .key("R")
         .enabled(in_sketch)
-        .params("p0, p1: opposite corners [x,y]; construction?"),
+        .params("p0, p1: opposite corners [x,y]; construction?. Returns sides {bottom, right, top, left} (line ids) and corners {bottom_left, bottom_right, top_right, top_left} (point ids)"),
     CommandSpec::new("sketch.rectangle.three_point", "3-Point Rectangle", rect_three_point)
         .at("SKETCH", "CREATE")
         .icon("rect3")
@@ -37,7 +37,7 @@ pub static COMMANDS: &[CommandSpec] = &[
         .at("SKETCH", "CREATE")
         .icon("rect_center")
         .enabled(in_sketch)
-        .params("center, corner"),
+        .params("center, corner. Returns sides {bottom, right, top, left} (line ids) and corners {bottom_left, bottom_right, top_right, top_left} (point ids)"),
     CommandSpec::new("sketch.circle.center", "Center Diameter Circle", circle_center)
         .at("SKETCH", "CREATE")
         .icon("circle")
@@ -526,6 +526,27 @@ fn rect_constraints(sk: &mut Sketch, l: &[usize]) -> Result<Vec<String>> {
     Ok(cons)
 }
 
+/// Which side and corner of an axis-aligned rectangle is which, from its lines and corner
+/// points as `polygon_lines` made them (counter-clockwise from the bottom-left corner), so a
+/// caller can dimension it without inspecting the sketch first.
+fn rect_names(sk: &Sketch, l: &[usize], pts: &[usize]) -> Value {
+    let curve = |i: usize| l.get(i).and_then(|c| sk.curves.get(*c)).map(|c| c.id.clone());
+    let point = |i: usize| pts.get(i).and_then(|q| sk.points.get(*q)).map(|q| q.id.clone());
+    json!({
+        "sides": {"bottom": curve(0), "right": curve(1), "top": curve(2), "left": curve(3)},
+        "corners": {"bottom_left": point(0), "bottom_right": point(1), "top_right": point(2), "top_left": point(3)},
+    })
+}
+
+/// `result` plus the rectangle's named sides and corners.
+fn rect_result(sk_out: (Vec<String>, Vec<String>), names: Value, info: Value) -> Value {
+    let mut out = result(sk_out, info);
+    if let (Some(o), Value::Object(n)) = (out.as_object_mut(), names) {
+        o.extend(n);
+    }
+    out
+}
+
 fn rect_two_point(s: &mut Session, p: &Value) -> Result<Value> {
     let cmd = "sketch.rectangle.two_point";
     let (a, b) = (req_vec2(cmd, p, "p0")?, req_vec2(cmd, p, "p1")?);
@@ -533,13 +554,13 @@ fn rect_two_point(s: &mut Session, p: &Value) -> Result<Value> {
         return Err(bad(cmd, "the corners must differ in x and y"));
     }
     let (lo, hi) = (Vec2::new(a.x.min(b.x), a.y.min(b.y)), Vec2::new(a.x.max(b.x), a.y.max(b.y)));
-    let (out, info) = edit(s, p, cmd, false, |sk, _| {
-        let (l, _) = polygon_lines(sk, &[lo, Vec2::new(hi.x, lo.y), hi, Vec2::new(lo.x, hi.y)])?;
+    let ((out, names), info) = edit(s, p, cmd, false, |sk, _| {
+        let (l, pts) = polygon_lines(sk, &[lo, Vec2::new(hi.x, lo.y), hi, Vec2::new(lo.x, hi.y)])?;
         let cons = rect_constraints(sk, &l)?;
         mark_construction(sk, &l, p);
-        Ok((ids_of(sk, &l), cons))
+        Ok(((ids_of(sk, &l), cons), rect_names(sk, &l, &pts)))
     })?;
-    Ok(result(out, info))
+    Ok(rect_result(out, names, info))
 }
 
 fn rect_center(s: &mut Session, p: &Value) -> Result<Value> {
@@ -549,7 +570,7 @@ fn rect_center(s: &mut Session, p: &Value) -> Result<Value> {
     if h.x < 1e-9 || h.y < 1e-9 {
         return Err(bad(cmd, "the corner must differ from the centre in x and y"));
     }
-    let (out, info) = edit(s, p, cmd, false, |sk, _| {
+    let ((out, names), info) = edit(s, p, cmd, false, |sk, _| {
         let (l, pts) = polygon_lines(sk, &[c - h, Vec2::new(c.x + h.x, c.y - h.y), c + h, Vec2::new(c.x - h.x, c.y + h.y)])?;
         let mut cons = rect_constraints(sk, &l)?;
         // Both diagonals (construction), the centre at their crossing. Only the first carries
@@ -567,9 +588,9 @@ fn rect_center(s: &mut Session, p: &Value) -> Result<Value> {
             cons.push(add_c(sk, ConstraintKind::Midpoint { p: cp, l: diag })?);
         }
         mark_construction(sk, &l, p);
-        Ok((ids_of(sk, &l), cons))
+        Ok(((ids_of(sk, &l), cons), rect_names(sk, &l, &pts)))
     })?;
-    Ok(result(out, info))
+    Ok(rect_result(out, names, info))
 }
 
 fn rect_three_point(s: &mut Session, p: &Value) -> Result<Value> {
diff --git a/crates/engine/src/tests.rs b/crates/engine/src/tests.rs
index 8c8697cc..df715a0b 100644
--- a/crates/engine/src/tests.rs
+++ b/crates/engine/src/tests.rs
@@ -1847,3 +1847,43 @@ fn boundary_fill_cells() {
     assert!(rel(m["total"]["volume_mm3"].as_f64().unwrap_or(0.0), 2.0 * 10.0 * 20.0 * 20.0) < 1e-9, "{m}");
     assert!(s.execute("SurfaceSculpt", &json!({"tools": ["A"], "cells": [[100, 100, 100]]})).is_err());
 }
+
+/// Rectangles name their sides and corners, so they can be dimensioned without inspecting the
+/// sketch first, whichever way round the corners were given.
+#[test]
+fn rectangle_names_sides_and_corners() {
+    let mut s = Session::default();
+    run(&mut s, "sketch.create", json!({"plane": "XY"}));
+    let r = run(&mut s, "sketch.rectangle.two_point", json!({"p0": [40, 30], "p1": [0, 0]}));
+    let pos = |s: &Session, id: &Value| {
+        let sk = s.doc.sketch(s.active_sketch.unwrap()).unwrap();
+        sk.point(sk.resolve_point(id.as_str().unwrap()).unwrap()).unwrap()
+    };
+    for (corner, at) in [("bottom_left", [0.0, 0.0]), ("bottom_right", [40.0, 0.0]), ("top_right", [40.0, 30.0]), ("top_left", [0.0, 30.0])] {
+        let p = pos(&s, &r["corners"][corner]);
+        assert!((p.x - at[0]).abs() < 1e-9 && (p.y - at[1]).abs() < 1e-9, "{corner}: {p:?} in {r}");
+    }
+    for (side, from, to) in [
+        ("bottom", "bottom_left", "bottom_right"),
+        ("right", "bottom_right", "top_right"),
+        ("top", "top_right", "top_left"),
+        ("left", "top_left", "bottom_left"),
+    ] {
+        let line = r["sides"][side].as_str().unwrap();
+        assert!(r["curves"].as_array().unwrap().iter().any(|c| c == line), "{r}");
+        assert_eq!(pos(&s, &json!(format!("{line}.start"))), pos(&s, &r["corners"][from]), "{side} in {r}");
+        assert_eq!(pos(&s, &json!(format!("{line}.end"))), pos(&s, &r["corners"][to]), "{side} in {r}");
+    }
+    run(&mut s, "sketch.constraint.coincident", json!({"a": r["corners"]["bottom_left"], "b": "origin"}));
+    run(&mut s, "sketch.dimension", json!({"entities": [r["sides"]["bottom"]], "value": 50}));
+    run(&mut s, "sketch.dimension", json!({"entities": [r["sides"]["left"]], "value": 20}));
+    let si = run(&mut s, "sketch.inspect", json!({}));
+    assert_eq!(si["dof"], 0, "{si}");
+    let p = pos(&s, &r["corners"]["top_right"]);
+    assert!((p.x - 50.0).abs() < 1e-6 && (p.y - 20.0).abs() < 1e-6, "{p:?}");
+
+    let c = run(&mut s, "sketch.rectangle.center", json!({"center": [100, 0], "corner": [90, 5]}));
+    let p = pos(&s, &c["corners"]["bottom_left"]);
+    assert!((p.x - 90.0).abs() < 1e-9 && (p.y + 5.0).abs() < 1e-9, "{c}");
+    assert_eq!(pos(&s, &json!(format!("{}.start", c["sides"]["top"].as_str().unwrap()))), pos(&s, &c["corners"]["top_right"]), "{c}");
+}