Rib/Web: grow along the sketch normal (#2056) (#2057)

Thanks @pablopeza.

assets/locales/cs.json

@@ -82,6 +82,7 @@
   "Density": "Hustota",
   "Designs you open or save appear here.": "Zde se zobrazí návrhy, které otevřete nebo uložíte.",
   "Determined by To Object. Choose Angle to edit the angular extent.": "Určeno volbou K objektu. Pro úpravu úhlového rozsahu zvolte Úhel.",
+  "Direction": "Směr",
   "Discard": "Zahodit",
   "Do not export hidden edges": "Neexportovat skryté hrany",
   "Double-click to rename": "Dvojklikem přejmenujete",
@@ -121,6 +122,7 @@
   "Home view": "Výchozí pohled",
   "In This Design": "V tomto návrhu",
   "In place (surfaces)": "Na místě (plochy)",
+  "In plane": "V rovině",
   "Inside": "Uvnitř",
   "Interferes": "Koliduje",
   "Issue title": "Název hlášení",
@@ -154,6 +156,7 @@
   "No matching appearances": "Žádné odpovídající vzhledy",
   "No visible bodies to export.": "Žádná viditelná tělesa k exportu.",
   "None": "Žádné",
+  "Normal to sketch": "Kolmo ke skice",
   "Not available yet": "Zatím není k dispozici",
   "Notch": "Zářez",
   "Opacity": "Neprůhlednost",

assets/locales/de.json

@@ -26,6 +26,7 @@
   "Current orthographic view (1:1 mm)": "Aktuelle orthogonale Ansicht (1:1 mm)",
   "Current perspective view": "Aktuelle perspektivische Ansicht",
   "Curvature (G2)": "Krümmung (G2)",
+  "Direction": "Richtung",
   "Do not export hidden edges": "Verdeckte Kanten nicht exportieren",
   "Don't ask again": "Nicht mehr fragen",
   "Drive Joint": "Gelenk antreiben",
@@ -47,6 +48,7 @@
   "Holes": "Löcher",
   "Holes (edges on them)": "Löcher (ihre Kanten)",
   "In place (surfaces)": "An Ort und Stelle (Flächen)",
+  "In plane": "In der Ebene",
   "Inside": "Innen",
   "Length": "Länge",
   "Max": "Max",
@@ -55,6 +57,7 @@
   "New study": "Neue Untersuchung",
   "No visible bodies to export.": "Keine sichtbaren Körper zum Exportieren.",
   "None": "Keine",
+  "Normal to sketch": "Normal zur Skizze",
   "Notch": "Ausklinkung",
   "Outside": "Außen",
   "Overall length": "Gesamtlänge",

assets/locales/en.json

@@ -86,6 +86,7 @@
   "Density": "Density",
   "Designs you open or save appear here.": "Designs you open or save appear here.",
   "Determined by To Object. Choose Angle to edit the angular extent.": "Determined by To Object. Choose Angle to edit the angular extent.",
+  "Direction": "Direction",
   "Discard": "Discard",
   "Do not export hidden edges": "Do not export hidden edges",
   "Don't ask again": "Don't ask again",
@@ -128,6 +129,7 @@
   "Home view": "Home view",
   "In This Design": "In This Design",
   "In place (surfaces)": "In place (surfaces)",
+  "In plane": "In plane",
   "Inside": "Inside",
   "Interferes": "Interferes",
   "Issue title": "Issue title",
@@ -163,6 +165,7 @@
   "No matching appearances": "No matching appearances",
   "No visible bodies to export.": "No visible bodies to export.",
   "None": "None",
+  "Normal to sketch": "Normal to sketch",
   "Not available yet": "Not available yet",
   "Notch": "Notch",
   "Opacity": "Opacity",

assets/locales/es.json

@@ -82,6 +82,7 @@
   "Density": "Densidad",
   "Designs you open or save appear here.": "Aquí aparecen los diseños que abras o guardes.",
   "Determined by To Object. Choose Angle to edit the angular extent.": "Determinado por «Hasta objeto». Elige «Ángulo» para modificar la extensión angular.",
+  "Direction": "Dirección",
   "Discard": "Descartar",
   "Do not export hidden edges": "No exportar aristas ocultas",
   "Double-click to rename": "Doble clic para cambiar el nombre",
@@ -120,6 +121,7 @@
   "Home view": "Vista de inicio",
   "In This Design": "En este diseño",
   "In place (surfaces)": "En su posición (superficies)",
+  "In plane": "En el plano",
   "Inside": "Interior",
   "Interferes": "Interfiere",
   "Issue title": "Título de la incidencia",
@@ -153,6 +155,7 @@
   "No matching appearances": "No hay apariencias coincidentes",
   "No visible bodies to export.": "No hay cuerpos visibles para exportar.",
   "None": "Ninguno",
+  "Normal to sketch": "Normal al boceto",
   "Not available yet": "Todavía no disponible",
   "Notch": "Muesca",
   "Opacity": "Opacidad",

assets/locales/fr.json

@@ -86,6 +86,7 @@
   "Density": "Masse volumique",
   "Designs you open or save appear here.": "Les conceptions que vous ouvrez ou enregistrez apparaissent ici.",
   "Determined by To Object. Choose Angle to edit the angular extent.": "Déterminé par Jusqu'à l'objet. Choisir Angle pour modifier l'étendue angulaire.",
+  "Direction": "Direction",
   "Discard": "Abandonner",
   "Do not export hidden edges": "Ne pas exporter les arêtes cachées",
   "Don't ask again": "Ne plus demander",
@@ -127,6 +128,7 @@
   "Home view": "Vue d'accueil",
   "In This Design": "Dans cette conception",
   "In place (surfaces)": "En place (surfaces)",
+  "In plane": "Dans le plan",
   "Inside": "Intérieur",
   "Interferes": "Interfère",
   "Issue title": "Titre du ticket",
@@ -161,6 +163,7 @@
   "No matching appearances": "Aucune apparence correspondante",
   "No visible bodies to export.": "Aucun corps visible à exporter.",
   "None": "Aucun",
+  "Normal to sketch": "Normale à l'esquisse",
   "Not available yet": "Pas encore disponible",
   "Notch": "Encoche",
   "Opacity": "Opacité",

assets/locales/gl.json

@@ -82,6 +82,7 @@
   "Density": "Densidade",
   "Designs you open or save appear here.": "Os deseños que abras ou gardes aparecen aquí.",
   "Determined by To Object. Choose Angle to edit the angular extent.": "Determinado por Ata o obxecto. Escolle Ángulo para editar a extensión angular.",
+  "Direction": "Dirección",
   "Discard": "Descartar",
   "Do not export hidden edges": "Non exportar as arestas ocultas",
   "Double-click to rename": "Dobre clic para renomear",
@@ -121,6 +122,7 @@
   "Home view": "Vista de inicio",
   "In This Design": "Neste deseño",
   "In place (surfaces)": "No sitio (superficies)",
+  "In plane": "No plano",
   "Inside": "Dentro",
   "Interferes": "Interfire",
   "Issue title": "Título da incidencia",
@@ -154,6 +156,7 @@
   "No matching appearances": "Non hai aparencias coincidentes",
   "No visible bodies to export.": "Non hai corpos visibles para exportar.",
   "None": "Ningún",
+  "Normal to sketch": "Normal ao bosquexo",
   "Not available yet": "Aínda non dispoñible",
   "Notch": "Entalle",
   "Opacity": "Opacidade",

assets/locales/ja.json

@@ -86,6 +86,7 @@
   "Density": "密度",
   "Designs you open or save appear here.": "開いたデザインや保存したデザインがここに表示されます。",
   "Determined by To Object. Choose Angle to edit the angular extent.": "「対象オブジェクトまで」により決定されます。角度範囲を編集するには「角度」を選択してください。",
+  "Direction": "方向",
   "Discard": "破棄",
   "Do not export hidden edges": "出力しない",
   "Don't ask again": "今後確認しない",
@@ -128,6 +129,7 @@
   "Home view": "ホームビュー",
   "In This Design": "このデザイン内",
   "In place (surfaces)": "その場で（サーフェス）",
+  "In plane": "平面内",
   "Inside": "内側",
   "Interferes": "干渉あり",
   "Issue title": "Issueタイトル",
@@ -163,6 +165,7 @@
   "No matching appearances": "一致する外観がありません",
   "No visible bodies to export.": "出力する表示中のボディがありません。",
   "None": "なし",
+  "Normal to sketch": "スケッチに垂直",
   "Not available yet": "まだ利用できません",
   "Notch": "ノッチ",
   "Opacity": "不透明度",

assets/locales/ko.json

@@ -26,6 +26,7 @@
   "Current orthographic view (1:1 mm)": "현재 직교 투영 뷰 (1:1 mm)",
   "Current perspective view": "현재 원근 투영 뷰",
   "Curvature (G2)": "곡률 (G2)",
+  "Direction": "방향",
   "Do not export hidden edges": "숨겨진 모서리 내보내지 않기",
   "Don't ask again": "다시 묻지 않기",
   "Drive Joint": "조인트 구동",
@@ -47,6 +48,7 @@
   "Holes": "구멍",
   "Holes (edges on them)": "구멍 (구멍의 모서리)",
   "In place (surfaces)": "제자리에서 (서피스)",
+  "In plane": "평면 내",
   "Inside": "안쪽",
   "Length": "길이",
   "Max": "최대",
@@ -55,6 +57,7 @@
   "New study": "새 연구",
   "No visible bodies to export.": "표시된 바디가 없어 내보낼 수 없습니다.",
   "None": "없음",
+  "Normal to sketch": "스케치에 수직",
   "Notch": "노치",
   "Outside": "바깥쪽",
   "Overall length": "전체 길이",

assets/locales/pt-BR.json

@@ -82,6 +82,7 @@
   "Density": "Densidade",
   "Designs you open or save appear here.": "Os projetos que você abrir ou salvar aparecem aqui.",
   "Determined by To Object. Choose Angle to edit the angular extent.": "Determinado por Até o objeto. Escolha Ângulo para editar a extensão angular.",
+  "Direction": "Direção",
   "Discard": "Descartar",
   "Do not export hidden edges": "Não exportar arestas ocultas",
   "Double-click to rename": "Clique duas vezes para renomear",
@@ -121,6 +122,7 @@
   "Home view": "Vista inicial",
   "In This Design": "Neste projeto",
   "In place (surfaces)": "No lugar (superfícies)",
+  "In plane": "No plano",
   "Inside": "Dentro",
   "Interferes": "Interfere",
   "Issue title": "Título da issue",
@@ -154,6 +156,7 @@
   "No matching appearances": "Nenhuma aparência correspondente",
   "No visible bodies to export.": "Nenhum corpo visível para exportar.",
   "None": "Nenhum",
+  "Normal to sketch": "Normal ao esboço",
   "Not available yet": "Ainda não disponível",
   "Notch": "Entalhe",
   "Opacity": "Opacidade",

assets/locales/ru.json

@@ -76,6 +76,7 @@
   "Density": "Плотность",
   "Designs you open or save appear here.": "Здесь появляются открытые и сохранённые дизайны.",
   "Determined by To Object. Choose Angle to edit the angular extent.": "Определяется параметром «До объекта». Выберите «Угол», чтобы задать угловой предел.",
+  "Direction": "Направление",
   "Discard": "Отменить",
   "Double-click to rename": "Двойной щелчок — переименовать",
   "Double-clicking the middle button in the view: Home (the home view, framing what is shown), Fit (frame what is shown, keeping the orientation) or nothing": "Двойной щелчок средней кнопкой в виде: «Главная» (главный вид, кадрирует показанное), «Вписать» (кадрирует, сохраняя ориентацию) или ничего",
@@ -106,6 +107,7 @@
   "Height": "Высота",
   "Home view": "Главный вид",
   "In This Design": "В этом дизайне",
+  "In plane": "В плоскости",
   "Interferes": "Пересекается",
   "Issue title": "Заголовок Issue",
   "Joint Origin1": "Точка сопряжения1",
@@ -134,6 +136,7 @@
   "New study": "Новое исследование",
   "No crash reports.": "Нет отчётов о сбоях.",
   "No matching appearances": "Нет подходящих внешних видов",
+  "Normal to sketch": "По нормали к эскизу",
   "Not available yet": "Пока недоступно",
   "Notch": "Вырез",
   "Opacity": "Непрозрачность",

assets/locales/tr.json

@@ -80,6 +80,7 @@
   "Density": "Yoğunluk",
   "Designs you open or save appear here.": "Açtığınız veya kaydettiğiniz tasarımlar burada görünür.",
   "Determined by To Object. Choose Angle to edit the angular extent.": "Nesneye kadar seçeneğiyle belirlenir. Açısal kapsamı düzenlemek için Açı seçeneğini seçin.",
+  "Direction": "Yön",
   "Discard": "At",
   "Double-click to rename": "Yeniden adlandırmak için çift tıklayın",
   "Double-clicking the middle button in the view: Home (the home view, framing what is shown), Fit (frame what is shown, keeping the orientation) or nothing": "Görünümde orta tuşla çift tıklama: Başlangıç (gösterileni çerçeveleyen başlangıç görünümü), Sığdır (yönü koruyarak gösterileni çerçeveler) veya hiçbir şey",
@@ -114,6 +115,7 @@
   "Home view": "Başlangıç görünümü",
   "In This Design": "Bu tasarımda",
   "In place (surfaces)": "Yerinde (yüzeyler)",
+  "In plane": "Düzlemde",
   "Inside": "İç",
   "Interferes": "Girişim var",
   "Issue title": "Sorun başlığı",
@@ -147,6 +149,7 @@
   "No crash reports.": "Çökme raporu yok.",
   "No matching appearances": "Eşleşen görünüm yok",
   "None": "Hiçbiri",
+  "Normal to sketch": "Eskize dik",
   "Not available yet": "Henüz kullanılamıyor",
   "Opacity": "Opaklık",
   "Open GitHub draft": "GitHub taslağını aç",

assets/locales/uk.json

@@ -86,6 +86,7 @@
   "Density": "Густина",
   "Designs you open or save appear here.": "Проєкти, які ви відкриваєте чи зберігаєте, з'являються тут.",
   "Determined by To Object. Choose Angle to edit the angular extent.": "Визначається об'єктом призначення. Виберіть «Кут», щоб редагувати кутову протяжність.",
+  "Direction": "Напрямок",
   "Discard": "Відхилити",
   "Do not export hidden edges": "Не експортувати приховані ребра",
   "Double-click to rename": "Двічі клацніть, щоб перейменувати",
@@ -126,6 +127,7 @@
   "Home view": "Головний вид",
   "In This Design": "У цьому проєкті",
   "In place (surfaces)": "На місці (поверхні)",
+  "In plane": "У площині",
   "Inside": "Усередину",
   "Interferes": "Перетинається",
   "Issue title": "Заголовок повідомлення",
@@ -160,6 +162,7 @@
   "No matching appearances": "Немає відповідних виглядів",
   "No visible bodies to export.": "Немає видимих тіл для експорту.",
   "None": "Немає",
+  "Normal to sketch": "За нормаллю до ескізу",
   "Not available yet": "Ще недоступно",
   "Notch": "Виріз",
   "Opacity": "Непрозорість",

assets/locales/zh.json

@@ -86,6 +86,7 @@
   "Density": "密度",
   "Designs you open or save appear here.": "你打开或保存的设计会显示在此处。",
   "Determined by To Object. Choose Angle to edit the angular extent.": "由“到对象”确定。选择“角度”可编辑角度范围。",
+  "Direction": "方向",
   "Discard": "放弃",
   "Do not export hidden edges": "不导出隐藏线",
   "Don't ask again": "不再询问",
@@ -128,6 +129,7 @@
   "Home view": "主视图",
   "In This Design": "在此设计中",
   "In place (surfaces)": "原位（曲面）",
+  "In plane": "在平面内",
   "Inside": "内侧",
   "Interferes": "发生干涉",
   "Issue title": "Issue 标题",
@@ -163,6 +165,7 @@
   "No matching appearances": "没有匹配的外观",
   "No visible bodies to export.": "没有可导出的可见实体。",
   "None": "无",
+  "Normal to sketch": "垂直于草图",
   "Not available yet": "暂不可用",
   "Notch": "缺口",
   "Opacity": "不透明度",

crates/doc/src/document.rs

@@ -901,7 +901,8 @@ pub enum FeatureKind {
         targets: Vec<BodyName>,
     },
     /// A thin wall from open sketch curves: `thickness` across the sketch plane, filling from
-    /// the curves toward the body (to the next face, or `depth`). A web makes one per curve.
+    /// the curves toward the body (to the next face, or `depth`), or with `normal` along the
+    /// sketch normal. A web makes one per curve.
     Rib {
         sketch: SketchId,
         curves: Vec<String>,
@@ -917,6 +918,10 @@ pub enum FeatureKind {
         /// Web: each curve is its own wall.
         #[serde(default, skip_serializing_if = "std::ops::Not::not")]
         web: bool,
+        /// Grow the wall along the sketch normal (thickness across the curves, in the sketch
+        /// plane) instead of across the plane from the curves.
+        #[serde(default, skip_serializing_if = "std::ops::Not::not")]
+        normal: bool,
     },
     /// Move planar faces (at the given points) onto a target plane parallel to them.
     ReplaceFace {

crates/doc/src/eval_more.rs

@@ -69,7 +69,7 @@ pub(super) fn eval(doc: &Document, vals: &BTreeMap<String, Value>, f: &Feature,
             }
             apply_op(st, f, tools, if *deboss { Operation::Cut } else { Operation::Join }, &crate::plain(targets))
         }
-        FeatureKind::Rib { sketch, curves, thickness, depth, flip, web } => {
+        FeatureKind::Rib { sketch, curves, thickness, depth, flip, web, normal } => {
             let ss = st.sketch(sketch.0).ok_or_else(|| DocError::Unknown(format!("sketch {sketch}")))?.clone();
             let t = val(vals, thickness, Kind::Length)?;
             if !(t > 0.0) {
@@ -88,7 +88,7 @@ pub(super) fn eval(doc: &Document, vals: &BTreeMap<String, Value>, f: &Feature,
             }
             let mut tools = Vec::new();
             for g in &groups {
-                tools.push(rib_tool(st, &ss, g, t, depth, *flip)?);
+                tools.push(if *normal { rib_tool_normal(st, &ss, g, t, depth, *flip)? } else { rib_tool(st, &ss, g, t, depth, *flip)? });
             }
             apply_op(st, f, tools, Operation::Join, &[])
         }
@@ -286,6 +286,83 @@ fn rib_tool(st: &ModelState, ss: &SolvedSketch, ids: &[String], t: f64, depth: O
     tools.into_iter().next().ok_or_else(|| DocError::Invalid("the rib made no solid".into()))
 }
 
+/// A rib wall along the sketch normal: the curves widened to `t` in the sketch plane, run from
+/// the sketch toward the body by `depth` (or until the whole wall reaches the body).
+fn rib_tool_normal(st: &ModelState, ss: &SolvedSketch, ids: &[String], t: f64, depth: Option<f64>, flip: bool) -> Result<Body> {
+    let pts = chain_points(ss, ids)?;
+    let len: f64 = pts.windows(2).map(|w| w[0].dist(w[1])).sum();
+    if !(len > 1e-9) {
+        return Err(DocError::Invalid("a zero-length rib curve".into()));
+    }
+    let samples = ((len / (t * 0.5).max(len / 400.0)).ceil() as usize).clamp(2, 400);
+    let along: Vec<Vec3> = (0..=samples).map(|k| ss.plane.to_world(point_on_polyline(&pts, len * k as f64 / samples as f64))).collect();
+    let normal = ss.plane.normal();
+    let reach = st.bodies.iter().map(|b| b.mesh().bounds()).fold(0.0f64, |acc, bb| acc.max((bb.max - bb.min).len()));
+    let inside = |q: Vec3| st.bodies.iter().any(|b| b.mesh().contains(q));
+    // Where the body begins from each point of the curves, along `sign` × the sketch normal.
+    let limit = reach * 2.0 + 1.0;
+    let step = (limit / 400.0).max(1e-3);
+    let hits = |sign: f64| -> Vec<f64> {
+        let mut out = Vec::new();
+        for q in &along {
+            let Some(k) = (1..=400).find(|k| inside(*q + normal * (sign * *k as f64 * step))) else { continue };
+            let (mut lo, mut hi) = ((k - 1) as f64 * step, k as f64 * step);
+            for _ in 0..30 {
+                let m = 0.5 * (lo + hi);
+                if inside(*q + normal * (sign * m)) { hi = m } else { lo = m }
+            }
+            out.push(hi);
+        }
+        out
+    };
+    // Toward the material: the side of the sketch where the curves meet the bodies (unless flipped).
+    let (front, back) = (hits(1.0), hits(-1.0));
+    let mut sign = if back.len() > front.len() { -1.0 } else { 1.0 };
+    let mut reached = if sign > 0.0 { front } else { back };
+    if flip {
+        sign = -sign;
+        reached = hits(sign);
+    }
+    let h = match depth {
+        Some(d) => d,
+        None => {
+            let far = reached.iter().copied().fold(f64::NAN, f64::max);
+            if !far.is_finite() {
+                return Err(DocError::Invalid("the rib curves do not face a body along the sketch normal (give a depth)".into()));
+            }
+            far + (t * 0.5).max(step)
+        }
+    };
+    // The curves widened to `t`: each point offset by half the thickness along the miter of its
+    // neighbours, both sides joined into one band.
+    let half = t / 2.0;
+    let mut left = Vec::with_capacity(pts.len());
+    let mut right = Vec::with_capacity(pts.len());
+    for (i, p) in pts.iter().enumerate() {
+        let prev = i.checked_sub(1).and_then(|j| pts.get(j)).and_then(|q| (*p - *q).normalized());
+        let next = pts.get(i + 1).and_then(|q| (*q - *p).normalized());
+        let (n, scale) = match (prev, next) {
+            (Some(a), Some(b)) => {
+                let m = (a.perp() + b.perp()).normalized().unwrap_or(a.perp());
+                (m, 1.0 / m.dot(a.perp()).max(0.25))
+            }
+            (Some(a), None) | (None, Some(a)) => (a.perp(), 1.0),
+            (None, None) => continue,
+        };
+        left.push(*p + n * (half * scale));
+        right.push(*p - n * (half * scale));
+    }
+    left.extend(right.into_iter().rev());
+    let mut lp = Loop2::polygon(&left);
+    if lp.signed_area() < 0.0 {
+        lp = lp.reversed();
+    }
+    let region = Region2 { outer: lp, holes: Vec::new() };
+    let (a, b) = if sign > 0.0 { (0.0, h) } else { (-h, 0.0) };
+    let tools = kernel::extrude(&ss.plane, &[region], a, b)?;
+    tools.into_iter().next().ok_or_else(|| DocError::Invalid("the rib made no solid".into()))
+}
+
 /// The point `d` along a polyline.
 fn point_on_polyline(pts: &[Vec2], d: f64) -> Vec2 {
     let mut left = d.max(0.0);

crates/doc/src/format/pending/rib-normal-direction.rs

@@ -0,0 +1,4 @@
+//! A Rib or Web can grow along the sketch normal (`normal: true`): the wall is `thickness` wide
+//! across its curves in the sketch plane and runs from the sketch toward the body. Older designs
+//! need no transformation: a rib without `normal` grows across the sketch plane as before; 0.14.x
+//! asks for an update instead of building a normal rib in the plane.

crates/engine/src/cmd/features_more.rs

@@ -25,11 +25,11 @@ pub static COMMANDS: &[CommandSpec] = &[
     CommandSpec::new("solid.rib", "Rib", rib)
         .at("SOLID", "CREATE")
         .icon("rib")
-        .params("sketch, curves: [open curve ids, in order]; thickness (across the sketch plane); depth? (default: to the next face); flip?: bool (fill to the other side)"),
+        .params("sketch, curves: [open curve ids, in order]; thickness (across the sketch plane, or across the curves when normal); depth? (default: to the next face); flip?: bool (fill to the other side); direction?: in_plane|normal (grow across the sketch plane, the default, or along its normal)"),
     CommandSpec::new("solid.web", "Web", web)
         .at("SOLID", "CREATE")
         .icon("web")
-        .params("sketch, curves: [open curve ids] (one wall each); thickness; depth? (default: to the next face); flip?: bool"),
+        .params("sketch, curves: [open curve ids] (one wall each); thickness; depth? (default: to the next face); flip?: bool; direction?: in_plane|normal"),
     CommandSpec::new("solid.emboss", "Emboss", emboss)
         .at("SOLID", "CREATE")
         .icon("emboss")
@@ -133,7 +133,12 @@ fn rib_like(s: &mut Session, p: &Value, cmd: &str, web: bool) -> Result<Value> {
         check_expr(s, d, Kind::Length, cmd, "depth")?;
     }
     let flip = bool_(p, "flip").unwrap_or(false);
-    add_feature(s, p, FeatureKind::Rib { sketch: SketchId(sketch), curves, thickness, depth, flip, web })
+    let normal = match str_(p, "direction").map(str::to_ascii_lowercase).as_deref() {
+        None | Some("in_plane" | "plane") => false,
+        Some("normal") => true,
+        Some(o) => return Err(bad(cmd, format!("unknown direction `{o}` (in_plane or normal)"))),
+    };
+    add_feature(s, p, FeatureKind::Rib { sketch: SketchId(sketch), curves, thickness, depth, flip, web, normal })
 }
 
 fn rib(s: &mut Session, p: &Value) -> Result<Value> {

crates/engine/src/cmd/features_more_tests.rs

@@ -77,6 +77,28 @@ fn rib_with_a_depth_and_web() {
     assert!(e.is_err_and(|e| e.to_string().contains("do not face a body")));
 }
 
+#[test]
+fn rib_along_the_sketch_normal_reaches_the_body() {
+    // A 20 x 20 x 10 box; a line along X on a sketch 10 in front of it (y = -10), whose plane
+    // the box does not cross, so only a rib along the sketch normal can reach it.
+    let mut s = Session::default();
+    run(&mut s, "solid.box", json!({"length": 20, "width": 20, "height": 10, "corner": [0, 0, 0]}));
+    run(&mut s, "sketch.create", json!({"plane": {"origin": [0, -10, 0], "x_dir": [1, 0, 0], "y_dir": [0, 0, 1]}, "name": "Front"}));
+    run(&mut s, "sketch.line", json!({"points": [[2, 5], [18, 5]], "ids": ["l1"]}));
+    run(&mut s, "sketch.finish", json!({}));
+    let e = s.execute("solid.rib", &json!({"sketch": "Front", "curves": ["l1"], "thickness": 2}));
+    assert!(e.is_err_and(|e| e.to_string().contains("do not face a body")));
+    run(&mut s, "solid.rib", json!({"sketch": "Front", "curves": ["l1"], "thickness": 2, "direction": "normal"}));
+    // 16 long, 2 thick, 10 from the sketch to the box.
+    assert!(rel(volume(&mut s), 4000.0 + 320.0) < 1e-6, "{}", volume(&mut s));
+    assert_eq!(measure(&mut s)["body_count"], 1);
+    run(&mut s, "edit.undo", json!({}));
+    run(&mut s, "solid.rib", json!({"sketch": "Front", "curves": ["l1"], "thickness": 2, "direction": "normal", "depth": 4}));
+    assert!(rel(volume(&mut s), 4000.0 + 128.0) < 1e-6, "{}", volume(&mut s));
+    let e = s.execute("solid.rib", &json!({"sketch": "Front", "curves": ["l1"], "thickness": 2, "direction": "sideways"}));
+    assert!(e.is_err_and(|e| e.to_string().contains("unknown direction")));
+}
+
 #[test]
 fn emboss_and_deboss_on_a_face() {
     let mut s = Session::default();

crates/ui-egui/src/dialogs.rs

@@ -151,6 +151,8 @@ pub enum Kind {
         thickness: String,
         depth: String,
         flip: bool,
+        /// Grow along the sketch normal rather than across the plane.
+        normal: bool,
     },
     /// Raise or sink profiles of a sketch on a face.
     Emboss {
@@ -491,7 +493,7 @@ impl Dialog {
                 Dialog::new(Kind::Mirror, vec![SelInput::new("Objects", BODIES, true), SelInput::new("Mirror Plane", PLANES | PLANAR_FACES, false)])
             }
             "solid.rib" | "solid.web" => Dialog::new(
-                Kind::Rib { web: id == "solid.web", thickness: "2 mm".into(), depth: String::new(), flip: false },
+                Kind::Rib { web: id == "solid.web", thickness: "2 mm".into(), depth: String::new(), flip: false, normal: false },
                 vec![SelInput::new("Curves", CURVES, true)],
             ),
             "solid.emboss" => Dialog::new(
@@ -2701,7 +2703,12 @@ pub fn show(app: &mut SolveApp, ctx: &egui::Context) {
                         ui.end_row();
                     }
                     Kind::Split | Kind::ReplaceFace | Kind::Remove | Kind::Midplane => {}
-                    Kind::Rib { thickness, depth, flip, .. } => {
+                    Kind::Rib { thickness, depth, flip, normal, .. } => {
+                        row_label(ui, "Direction");
+                        let mut i = usize::from(*normal);
+                        combo(ui, "rib_direction", &["In plane", "Normal to sketch"], &mut i);
+                        *normal = i == 1;
+                        ui.end_row();
                         row_label(ui, "Thickness");
                         enter |= field(ui, thickness);
                         ui.end_row();
@@ -3977,11 +3984,14 @@ fn dialog_commands(app: &SolveApp, d: &Dialog) -> Result<Vec<(String, Value)>, S
             };
             ("construct.plane.at_angle", json!({"base": base, "axis": axis, "angle": angle}))
         }
-        Kind::Rib { web, thickness, depth, flip } => {
+        Kind::Rib { web, thickness, depth, flip, normal } => {
             need(0, "open sketch curves")?;
             let curves = curve_ids(d, 0);
             let sketch = curves_sketch(app, &curves, None).ok_or("the curves must be in one sketch")?;
             let mut p = json!({"sketch": sketch, "curves": curves, "thickness": thickness, "flip": flip});
+            if *normal {
+                p["direction"] = json!("normal");
+            }
             if !depth.trim().is_empty() {
                 p["depth"] = json!(depth);
             }
@@ -5204,13 +5214,14 @@ pub fn for_feature(app: &SolveApp, id: u64, marker: Option<usize>) -> Option<Dia
             }
             d
         }
-        FeatureKind::Rib { curves, thickness, depth, flip, web, .. } => {
+        FeatureKind::Rib { curves, thickness, depth, flip, web, normal, .. } => {
             let mut d = start(if *web { "solid.web" } else { "solid.rib" })?;
             d.kind = Kind::Rib {
                 web: *web,
                 thickness: thickness.to_string(),
                 depth: depth.as_deref().map(str::to_string).unwrap_or_default(),
                 flip: *flip,
+                normal: *normal,
             };
             if let Some(inp) = d.inputs.first_mut() {
                 inp.items = curves.iter().map(|id| Sel::SketchCurve { id: id.clone() }).collect();