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src/modules/home/draw/circle.rs

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+// Circle tool — ribbon dropdown + all H7CAD circle creation methods.
+//
+// Methods:
+//   CIRCLE     — Center, Radius   (default)
+//   CIRCLE_CD  — Center, Diameter
+//   CIRCLE_2P  — 2-Point (two endpoints of diameter)
+//   CIRCLE_3P  — 3-Point (circumscribed circle through 3 points)
+//   CIRCLE_TTR — Tan, Tan, Radius (two tangent objects + radius)
+//   CIRCLE_TTT — Tan, Tan, Tan    (inscribed circle tangent to three objects)
+
+use acadrust::types::Vector3;
+use acadrust::{Circle, EntityType};
+
+use crate::command::{CadCommand, CmdResult, TangentObject};
+use crate::modules::home::defaults;
+use crate::modules::IconKind;
+use crate::scene::wire_model::WireModel;
+use glam::Vec3;
+
+const TAU: f32 = std::f32::consts::TAU;
+
+// ── Per-method SVG icons ───────────────────────────────────────────────────
+
+const ICON_CR: IconKind = IconKind::Svg(include_bytes!(
+    "../../../../assets/icons/circle/circle_cr.svg"
+));
+const ICON_CD: IconKind = IconKind::Svg(include_bytes!(
+    "../../../../assets/icons/circle/circle_cd.svg"
+));
+const ICON_2P: IconKind = IconKind::Svg(include_bytes!(
+    "../../../../assets/icons/circle/circle_2p.svg"
+));
+const ICON_3P: IconKind = IconKind::Svg(include_bytes!(
+    "../../../../assets/icons/circle/circle_3p.svg"
+));
+const ICON_TTR: IconKind = IconKind::Svg(include_bytes!(
+    "../../../../assets/icons/circle/circle_ttr.svg"
+));
+const ICON_TTT: IconKind = IconKind::Svg(include_bytes!(
+    "../../../../assets/icons/circle/circle_ttt.svg"
+));
+
+// ── Dropdown metadata (used by ribbon.rs) ─────────────────────────────────
+
+pub const DROPDOWN_ID: &str = "CIRCLE";
+
+pub const DROPDOWN_ITEMS: &[(&str, &str, IconKind)] = &[
+    ("CIRCLE", "Center, Radius", ICON_CR),
+    ("CIRCLE_CD", "Center, Diameter", ICON_CD),
+    ("CIRCLE_2P", "2-Point", ICON_2P),
+    ("CIRCLE_3P", "3-Point", ICON_3P),
+    ("CIRCLE_TTR", "Tan, Tan, Radius", ICON_TTR),
+    ("CIRCLE_TTT", "Tan, Tan, Tan", ICON_TTT),
+];
+
+/// Default icon — shown until first use (falls back to Center, Radius).
+pub const ICON: IconKind = ICON_CR;
+
+// ── Shared geometry ────────────────────────────────────────────────────────
+
+fn circle_wire(center: Vec3, radius: f32) -> WireModel {
+    let segs = 64u32;
+    let mut pts: Vec<[f32; 3]> = (0..=segs)
+        .map(|i| {
+            let a = (i as f32) * TAU / segs as f32;
+            [
+                center.x + radius * a.cos(),
+                center.y + radius * a.sin(),
+                center.z,
+            ]
+        })
+        .collect();
+    if let Some(first) = pts.first().cloned() {
+        pts.push(first);
+    }
+    WireModel::solid("rubber_band".into(), pts, WireModel::CYAN, false)
+}
+
+fn make_circle(center: Vec3, radius: f64) -> EntityType {
+    EntityType::Circle(Circle {
+        center: Vector3::new(center.x as f64, center.y as f64, center.z as f64),
+        radius,
+        ..Default::default()
+    })
+}
+
+/// Circumscribed circle through three points.
+/// Returns `None` if the points are collinear.
+fn circumcircle(a: Vec3, b: Vec3, c: Vec3) -> Option<(Vec3, f32)> {
+    let ax = a.x;
+    let ay = a.y;
+    let bx = b.x;
+    let by = b.y;
+    let cx = c.x;
+    let cy = c.y;
+    let d = 2.0 * (ax * (by - cy) + bx * (cy - ay) + cx * (ay - by));
+    if d.abs() < 1e-9 {
+        return None;
+    }
+    let ux = ((ax * ax + ay * ay) * (by - cy)
+        + (bx * bx + by * by) * (cy - ay)
+        + (cx * cx + cy * cy) * (ay - by))
+        / d;
+    let uy = ((ax * ax + ay * ay) * (cx - bx)
+        + (bx * bx + by * by) * (ax - cx)
+        + (cx * cx + cy * cy) * (bx - ax))
+        / d;
+    let center = Vec3::new(ux, uy, a.z);
+    Some((center, center.distance(a)))
+}
+
+// ── Command: Center, Radius ────────────────────────────────────────────────
+
+pub struct CircleCommand {
+    step: StepCR,
+    default_r: f32,
+}
+enum StepCR {
+    Center,
+    Radius(Vec3),
+}
+
+impl CircleCommand {
+    pub fn new() -> Self {
+        Self {
+            step: StepCR::Center,
+            default_r: defaults::get_circle_radius(),
+        }
+    }
+}
+
+impl CadCommand for CircleCommand {
+    fn name(&self) -> &'static str {
+        "CIRCLE"
+    }
+    fn prompt(&self) -> String {
+        match &self.step {
+            StepCR::Center => "CIRCLE  Specify center point:".into(),
+            StepCR::Radius(c) => format!(
+                "CIRCLE  Specify radius or type value  <{:.4}>  [center ({:.3},{:.3})]:",
+                self.default_r, c.x, c.y
+            ),
+        }
+    }
+    fn on_point(&mut self, pt: Vec3) -> CmdResult {
+        match &self.step {
+            StepCR::Center => {
+                self.step = StepCR::Radius(pt);
+                CmdResult::NeedPoint
+            }
+            StepCR::Radius(c) => {
+                let r = c.distance(pt);
+                defaults::set_circle_radius(r);
+                CmdResult::CommitAndExit(make_circle(*c, r as f64))
+            }
+        }
+    }
+    fn on_enter(&mut self) -> CmdResult {
+        if let StepCR::Radius(c) = &self.step {
+            let c = *c;
+            let r = self.default_r;
+            return CmdResult::CommitAndExit(make_circle(c, r as f64));
+        }
+        CmdResult::Cancel
+    }
+    fn on_escape(&mut self) -> CmdResult {
+        CmdResult::Cancel
+    }
+    fn on_mouse_move(&mut self, pt: Vec3) -> Option<WireModel> {
+        if let StepCR::Radius(c) = &self.step {
+            Some(circle_wire(*c, c.distance(pt)))
+        } else {
+            None
+        }
+    }
+    fn on_text_input(&mut self, text: &str) -> Option<CmdResult> {
+        if let StepCR::Radius(c) = &self.step {
+            let r: f32 = text.trim().replace(',', ".").parse().ok()?;
+            if r > 0.0 {
+                defaults::set_circle_radius(r);
+                return Some(CmdResult::CommitAndExit(make_circle(*c, r as f64)));
+            }
+        }
+        None
+    }
+}
+
+// ── Command: Center, Diameter ──────────────────────────────────────────────
+
+pub struct CircleCDCommand {
+    step: StepCR,
+    default_d: f32,
+}
+
+impl CircleCDCommand {
+    pub fn new() -> Self {
+        Self {
+            step: StepCR::Center,
+            default_d: defaults::get_circle_diam(),
+        }
+    }
+}
+
+impl CadCommand for CircleCDCommand {
+    fn name(&self) -> &'static str {
+        "CIRCLE_CD"
+    }
+    fn prompt(&self) -> String {
+        match &self.step {
+            StepCR::Center => "CIRCLE CD  Specify center point:".into(),
+            StepCR::Radius(c) => format!(
+                "CIRCLE CD  Specify diameter or type value  <{:.4}>  [center ({:.3},{:.3})]:",
+                self.default_d, c.x, c.y
+            ),
+        }
+    }
+    fn on_point(&mut self, pt: Vec3) -> CmdResult {
+        match &self.step {
+            StepCR::Center => {
+                self.step = StepCR::Radius(pt);
+                CmdResult::NeedPoint
+            }
+            StepCR::Radius(c) => {
+                let d = c.distance(pt) * 2.0;
+                defaults::set_circle_diam(d);
+                CmdResult::CommitAndExit(make_circle(*c, (d / 2.0) as f64))
+            }
+        }
+    }
+    fn on_enter(&mut self) -> CmdResult {
+        if let StepCR::Radius(c) = &self.step {
+            let c = *c;
+            let d = self.default_d;
+            return CmdResult::CommitAndExit(make_circle(c, (d / 2.0) as f64));
+        }
+        CmdResult::Cancel
+    }
+    fn on_escape(&mut self) -> CmdResult {
+        CmdResult::Cancel
+    }
+    fn on_mouse_move(&mut self, pt: Vec3) -> Option<WireModel> {
+        // Preview radius = distance to cursor; on commit that distance becomes the radius (diameter = 2x).
+        if let StepCR::Radius(c) = &self.step {
+            Some(circle_wire(*c, c.distance(pt)))
+        } else {
+            None
+        }
+    }
+    fn on_text_input(&mut self, text: &str) -> Option<CmdResult> {
+        if let StepCR::Radius(c) = &self.step {
+            let d: f32 = text.trim().replace(',', ".").parse().ok()?;
+            if d > 0.0 {
+                defaults::set_circle_diam(d);
+                return Some(CmdResult::CommitAndExit(make_circle(*c, (d / 2.0) as f64)));
+            }
+        }
+        None
+    }
+}
+
+// ── Command: 2-Point ──────────────────────────────────────────────────────
+
+pub struct Circle2PCommand {
+    p1: Option<Vec3>,
+}
+
+impl Circle2PCommand {
+    pub fn new() -> Self {
+        Self { p1: None }
+    }
+}
+
+impl CadCommand for Circle2PCommand {
+    fn name(&self) -> &'static str {
+        "CIRCLE_2P"
+    }
+    fn prompt(&self) -> String {
+        if self.p1.is_none() {
+            "CIRCLE 2P  Specify first end of diameter:".into()
+        } else {
+            "CIRCLE 2P  Specify second end of diameter:".into()
+        }
+    }
+    fn on_point(&mut self, pt: Vec3) -> CmdResult {
+        match self.p1 {
+            None => {
+                self.p1 = Some(pt);
+                CmdResult::NeedPoint
+            }
+            Some(p1) => {
+                let center = (p1 + pt) * 0.5;
+                let radius = p1.distance(pt) as f64 / 2.0;
+                CmdResult::CommitAndExit(make_circle(center, radius))
+            }
+        }
+    }
+    fn on_enter(&mut self) -> CmdResult {
+        CmdResult::Cancel
+    }
+    fn on_escape(&mut self) -> CmdResult {
+        CmdResult::Cancel
+    }
+    fn on_mouse_move(&mut self, pt: Vec3) -> Option<WireModel> {
+        let p1 = self.p1?;
+        let center = (p1 + pt) * 0.5;
+        let radius = p1.distance(pt) / 2.0;
+        Some(circle_wire(center, radius))
+    }
+}
+
+// ── Command: 3-Point ──────────────────────────────────────────────────────
+
+pub struct Circle3PCommand {
+    pts: Vec<Vec3>,
+}
+
+impl Circle3PCommand {
+    pub fn new() -> Self {
+        Self { pts: Vec::new() }
+    }
+}
+
+impl CadCommand for Circle3PCommand {
+    fn name(&self) -> &'static str {
+        "CIRCLE_3P"
+    }
+    fn prompt(&self) -> String {
+        match self.pts.len() {
+            0 => "CIRCLE 3P  Specify first point:".into(),
+            1 => "CIRCLE 3P  Specify second point:".into(),
+            _ => "CIRCLE 3P  Specify third point:".into(),
+        }
+    }
+    fn on_point(&mut self, pt: Vec3) -> CmdResult {
+        self.pts.push(pt);
+        if self.pts.len() < 3 {
+            return CmdResult::NeedPoint;
+        }
+        let (a, b, c) = (self.pts[0], self.pts[1], self.pts[2]);
+        match circumcircle(a, b, c) {
+            Some((center, radius)) => CmdResult::CommitAndExit(make_circle(center, radius as f64)),
+            None => {
+                self.pts.pop();
+                CmdResult::NeedPoint
+            } // collinear — ask again
+        }
+    }
+    fn on_enter(&mut self) -> CmdResult {
+        CmdResult::Cancel
+    }
+    fn on_escape(&mut self) -> CmdResult {
+        CmdResult::Cancel
+    }
+    fn on_mouse_move(&mut self, pt: Vec3) -> Option<WireModel> {
+        match self.pts.len() {
+            0 => None,
+            1 => {
+                // Show circle preview with p1→cursor as diameter (same as 2P).
+                let p1 = self.pts[0];
+                let center = (p1 + pt) * 0.5;
+                let radius = p1.distance(pt) / 2.0;
+                Some(circle_wire(center, radius))
+            }
+            _ => {
+                // Show circumcircle preview if non-collinear, else polyline.
+                let (a, b) = (self.pts[0], self.pts[1]);
+                if let Some((center, radius)) = circumcircle(a, b, pt) {
+                    Some(circle_wire(center, radius))
+                } else {
+                    Some(WireModel::solid(
+                        "rubber_band".into(),
+                        vec![[a.x, a.y, a.z], [b.x, b.y, b.z], [pt.x, pt.y, pt.z]],
+                        WireModel::CYAN,
+                        false,
+                    ))
+                }
+            }
+        }
+    }
+}
+
+// ── 2-D geometry for TTR/TTT ────────────────────────────────────
+
+#[derive(Clone, Copy)]
+struct Line2D {
+    a: f32,
+    b: f32,
+    c: f32,
+} // ax + by + c = 0, a²+b²=1
+
+impl Line2D {
+    fn from_obj(p1: Vec3, p2: Vec3) -> Self {
+        let dx = p2.x - p1.x;
+        let dy = p2.y - p1.y;
+        let len = (dx * dx + dy * dy).sqrt();
+        if len < 1e-9 {
+            return Self {
+                a: 1.0,
+                b: 0.0,
+                c: -p1.x,
+            };
+        }
+        let a = -dy / len;
+        let b = dx / len;
+        Self {
+            a,
+            b,
+            c: -(a * p1.x + b * p1.y),
+        }
+    }
+}
+
+fn line_line_isect(l1: Line2D, l2: Line2D) -> Option<Vec3> {
+    let det = l1.a * l2.b - l2.a * l1.b;
+    if det.abs() < 1e-9 {
+        return None;
+    }
+    let x = (-l1.c * l2.b + l2.c * l1.b) / det;
+    let y = (-l1.a * l2.c + l2.a * l1.c) / det;
+    Some(Vec3::new(x, y, 0.0))
+}
+
+fn solve_quadratic(a: f32, b: f32, c: f32) -> Vec<f32> {
+    if a.abs() < 1e-9 {
+        if b.abs() < 1e-9 {
+            return vec![];
+        }
+        return vec![-c / b];
+    }
+    let disc = b * b - 4.0 * a * c;
+    if disc < 0.0 {
+        return vec![];
+    }
+    let sq = disc.sqrt();
+    vec![(-b - sq) / (2.0 * a), (-b + sq) / (2.0 * a)]
+}
+
+fn best_of(candidates: &[Vec3], hint: Vec3) -> Option<Vec3> {
+    candidates.iter().copied().min_by(|a, b| {
+        a.distance(hint)
+            .partial_cmp(&b.distance(hint))
+            .unwrap_or(std::cmp::Ordering::Equal)
+    })
+}
+
+fn best_circle_of(candidates: &[(Vec3, f32)], hint: Vec3) -> Option<(Vec3, f32)> {
+    candidates
+        .iter()
+        .copied()
+        .filter(|&(_, r)| r > 1e-4)
+        .min_by(|(a, _), (b, _)| {
+            a.distance(hint)
+                .partial_cmp(&b.distance(hint))
+                .unwrap_or(std::cmp::Ordering::Equal)
+        })
+}
+
+/// All candidate circle centers tangent to two objects with radius r.
+fn ttr_candidates(obj1: TangentObject, obj2: TangentObject, r: f32) -> Vec<Vec3> {
+    match (obj1, obj2) {
+        (TangentObject::Line { p1: a, p2: b }, TangentObject::Line { p1: c, p2: d }) => {
+            let l1 = Line2D::from_obj(a, b);
+            let l2 = Line2D::from_obj(c, d);
+            let mut out = Vec::new();
+            for s1 in [-r, r] {
+                for s2 in [-r, r] {
+                    let ol1 = Line2D { c: l1.c + s1, ..l1 };
+                    let ol2 = Line2D { c: l2.c + s2, ..l2 };
+                    if let Some(pt) = line_line_isect(ol1, ol2) {
+                        out.push(pt);
+                    }
+                }
+            }
+            out
+        }
+        (
+            TangentObject::Line { p1, p2 },
+            TangentObject::Circle {
+                center: cp,
+                radius: cr,
+            },
+        )
+        | (
+            TangentObject::Circle {
+                center: cp,
+                radius: cr,
+            },
+            TangentObject::Line { p1, p2 },
+        ) => {
+            let l = Line2D::from_obj(p1, p2);
+            ttr_lc_candidates(l, cp, cr, r)
+        }
+        (
+            TangentObject::Circle {
+                center: c1,
+                radius: r1,
+            },
+            TangentObject::Circle {
+                center: c2,
+                radius: r2,
+            },
+        ) => ttr_cc_candidates(c1, r1, c2, r2, r),
+    }
+}
+
+fn ttr_lc_candidates(l: Line2D, cp: Vec3, cr: f32, r: f32) -> Vec<Vec3> {
+    let mut out = Vec::new();
+    for s1 in [-1.0f32, 1.0] {
+        for s2 in [-1.0f32, 1.0] {
+            let rho = cr + s2 * r;
+            if rho < 0.0 {
+                continue;
+            }
+            let c_off = l.c + s1 * r;
+            // The candidate center (cx, cy) satisfies:
+            //   l.a*cx + l.b*cy + c_off = 0
+            //   (cx - cp.x)^2 + (cy - cp.y)^2 = rho^2
+            // Parameterise cx = -l.b*t - l.a*c_off, cy = l.a*t - l.b*c_off
+            // where t is the free parameter along the offset line.
+            // Substituting into the circle equation:
+            //   (-l.b*t - l.a*c_off - cp.x)^2 + (l.a*t - l.b*c_off - cp.y)^2 = rho^2
+            // Let alpha = l.a*c_off + cp.x, beta = l.b*c_off + cp.y (using sign convention)
+            // Actually: u = -l.a*c_off - cp.x, v = -l.b*c_off - cp.y
+            let u = -(l.a * c_off) - cp.x;
+            let v = -(l.b * c_off) - cp.y;
+            // (-l.b*t + u)^2 + (l.a*t + v)^2 = rho^2
+            // (l.b^2 + l.a^2)*t^2 + 2*(-l.b*u + l.a*v)*t + (u^2 + v^2 - rho^2) = 0
+            // Since a^2 + b^2 = 1:
+            let qa = 1.0f32;
+            let qb = 2.0 * (-l.b * u + l.a * v);
+            let qc = u * u + v * v - rho * rho;
+            for t in solve_quadratic(qa, qb, qc) {
+                let cx = -l.b * t - l.a * c_off;
+                let cy = l.a * t - l.b * c_off;
+                out.push(Vec3::new(cx, cy, 0.0));
+            }
+        }
+    }
+    out
+}
+
+fn ttr_cc_candidates(c1: Vec3, r1: f32, c2: Vec3, r2: f32, r: f32) -> Vec<Vec3> {
+    let mut out = Vec::new();
+    for s1 in [-1.0f32, 1.0] {
+        for s2 in [-1.0f32, 1.0] {
+            let rho1 = r1 + s1 * r;
+            let rho2 = r2 + s2 * r;
+            if rho1 < 0.0 || rho2 < 0.0 {
+                continue;
+            }
+            let ax = c2.x - c1.x;
+            let ay = c2.y - c1.y;
+            let k = 0.5
+                * (rho1 * rho1 - rho2 * rho2 + c2.x * c2.x + c2.y * c2.y
+                    - c1.x * c1.x
+                    - c1.y * c1.y);
+            let a2 = ax * ax + ay * ay;
+            if a2 < 1e-12 {
+                continue;
+            }
+            if ay.abs() >= ax.abs() {
+                let iy = 1.0 / ay;
+                let qa = 1.0 + ax * ax * iy * iy;
+                let p = k * iy - c1.y;
+                let qb = -2.0 * (c1.x + ax * iy * p);
+                let qc = c1.x * c1.x + p * p - rho1 * rho1;
+                let disc = qb * qb - 4.0 * qa * qc;
+                if disc < 0.0 {
+                    continue;
+                }
+                for sign in [-1.0f32, 1.0] {
+                    let cx = (-qb + sign * disc.sqrt()) / (2.0 * qa);
+                    let cy = (k - ax * cx) * iy;
+                    out.push(Vec3::new(cx, cy, 0.0));
+                }
+            } else {
+                let ix = 1.0 / ax;
+                let qa = ay * ay * ix * ix + 1.0;
+                let p = k * ix - c1.x;
+                let qb = -2.0 * (ay * ix * p + c1.y);
+                let qc = p * p + c1.y * c1.y - rho1 * rho1;
+                let disc = qb * qb - 4.0 * qa * qc;
+                if disc < 0.0 {
+                    continue;
+                }
+                for sign in [-1.0f32, 1.0] {
+                    let cy = (-qb + sign * disc.sqrt()) / (2.0 * qa);
+                    let cx = (k - ay * cy) * ix;
+                    out.push(Vec3::new(cx, cy, 0.0));
+                }
+            }
+        }
+    }
+    out
+}
+
+/// Unified TTT solver: circle tangent to three objects. Returns all (center, radius) candidates.
+fn ttt_candidates(
+    obj1: TangentObject,
+    obj2: TangentObject,
+    obj3: TangentObject,
+) -> Vec<(Vec3, f32)> {
+    let objs = [obj1, obj2, obj3];
+    let mut results = Vec::new();
+    let sign_combos: [[f32; 3]; 8] = [
+        [-1., -1., -1.],
+        [-1., -1., 1.],
+        [-1., 1., -1.],
+        [-1., 1., 1.],
+        [1., -1., -1.],
+        [1., -1., 1.],
+        [1., 1., -1.],
+        [1., 1., 1.],
+    ];
+    for eps in &sign_combos {
+        for (center, r) in ttt_solve_sign(&objs, eps) {
+            if r > 1e-4 {
+                results.push((center, r));
+            }
+        }
+    }
+    results
+}
+
+// LinEq: lx*cx + ly*cy + lr*r = k
+struct LinEq {
+    lx: f32,
+    ly: f32,
+    lr: f32,
+    k: f32,
+}
+
+fn ttt_solve_sign(objs: &[TangentObject; 3], eps: &[f32; 3]) -> Vec<(Vec3, f32)> {
+    let mut lin_eqs: Vec<LinEq> = Vec::new();
+    let mut circle_idx: Vec<usize> = Vec::new();
+
+    for (i, &obj) in objs.iter().enumerate() {
+        match obj {
+            TangentObject::Line { p1, p2 } => {
+                let l = Line2D::from_obj(p1, p2);
+                lin_eqs.push(LinEq {
+                    lx: l.a,
+                    ly: l.b,
+                    lr: -eps[i],
+                    k: -l.c,
+                });
+            }
+            TangentObject::Circle { .. } => {
+                circle_idx.push(i);
+            }
+        }
+    }
+
+    // Circle-pair differences → additional linear equations
+    for j in 1..circle_idx.len() {
+        let i0 = circle_idx[0];
+        let i1 = circle_idx[j];
+        if let (
+            TangentObject::Circle {
+                center: p0,
+                radius: r0,
+            },
+            TangentObject::Circle {
+                center: p1,
+                radius: r1,
+            },
+        ) = (objs[i0], objs[i1])
+        {
+            let lx = 2.0 * (p1.x - p0.x);
+            let ly = 2.0 * (p1.y - p0.y);
+            let lr = -2.0 * (r0 * eps[i0] - r1 * eps[i1]);
+            let k = (r0 * r0 - r1 * r1) + p1.x * p1.x + p1.y * p1.y - p0.x * p0.x - p0.y * p0.y;
+            lin_eqs.push(LinEq { lx, ly, lr, k });
+        }
+    }
+
+    if lin_eqs.len() < 2 {
+        return vec![];
+    }
+
+    let e0 = &lin_eqs[0];
+    let e1 = &lin_eqs[1];
+    let det = e0.lx * e1.ly - e1.lx * e0.ly;
+    if det.abs() < 1e-9 {
+        return vec![];
+    }
+
+    // cx = a_cx + b_cx*r,  cy = a_cy + b_cy*r
+    let a_cx = (e0.k * e1.ly - e1.k * e0.ly) / det;
+    let b_cx = -(e0.lr * e1.ly - e1.lr * e0.ly) / det;
+    let a_cy = (e0.lx * e1.k - e1.lx * e0.k) / det;
+    let b_cy = -(e0.lx * e1.lr - e1.lx * e0.lr) / det;
+
+    let r_vals: Vec<f32> = if lin_eqs.len() >= 3 {
+        let e2 = &lin_eqs[2];
+        let r_coeff = b_cx * e2.lx + b_cy * e2.ly + e2.lr;
+        let r_const = e2.k - a_cx * e2.lx - a_cy * e2.ly;
+        if r_coeff.abs() < 1e-9 {
+            vec![]
+        } else {
+            vec![r_const / r_coeff]
+        }
+    } else if !circle_idx.is_empty() {
+        let ci = circle_idx[0];
+        if let TangentObject::Circle {
+            center: cp,
+            radius: cr,
+        } = objs[ci]
+        {
+            let p = a_cx - cp.x;
+            let q = a_cy - cp.y;
+            let e = eps[ci];
+            let a_q = b_cx * b_cx + b_cy * b_cy - e * e;
+            let b_q = 2.0 * (p * b_cx + q * b_cy - cr * e);
+            let c_q = p * p + q * q - cr * cr;
+            solve_quadratic(a_q, b_q, c_q)
+        } else {
+            vec![]
+        }
+    } else {
+        vec![]
+    };
+
+    r_vals
+        .into_iter()
+        .filter_map(|r| {
+            if r <= 1e-4 {
+                return None;
+            }
+            let cx = a_cx + b_cx * r;
+            let cy = a_cy + b_cy * r;
+            Some((Vec3::new(cx, cy, 0.0), r))
+        })
+        .collect()
+}
+
+// ── Command: Tan, Tan, Radius ──────────────────────────────────────────────
+
+pub struct CircleTTRCommand {
+    step: StepTTR,
+}
+
+enum StepTTR {
+    First,
+    Second {
+        obj1: TangentObject,
+        hit1: Vec3,
+    },
+    Radius {
+        obj1: TangentObject,
+        obj2: TangentObject,
+        hit1: Vec3,
+        hit2: Vec3,
+    },
+}
+
+impl CircleTTRCommand {
+    pub fn new() -> Self {
+        Self {
+            step: StepTTR::First,
+        }
+    }
+}
+
+impl CadCommand for CircleTTRCommand {
+    fn name(&self) -> &'static str {
+        "CIRCLE_TTR"
+    }
+
+    fn needs_tangent_pick(&self) -> bool {
+        matches!(self.step, StepTTR::First | StepTTR::Second { .. })
+    }
+
+    fn wants_text_input(&self) -> bool {
+        matches!(self.step, StepTTR::Radius { .. })
+    }
+
+    fn prompt(&self) -> String {
+        match &self.step {
+            StepTTR::First => "CIRCLE TTR  Select first tangent object:".into(),
+            StepTTR::Second { .. } => "CIRCLE TTR  Select second tangent object:".into(),
+            StepTTR::Radius { .. } => "CIRCLE TTR  Specify radius:".into(),
+        }
+    }
+
+    fn on_point(&mut self, _pt: Vec3) -> CmdResult {
+        CmdResult::NeedPoint
+    }
+
+    fn on_tangent_point(&mut self, obj: TangentObject, hit: Vec3) -> CmdResult {
+        match &self.step {
+            StepTTR::First => {
+                self.step = StepTTR::Second {
+                    obj1: obj,
+                    hit1: hit,
+                };
+                CmdResult::NeedPoint
+            }
+            StepTTR::Second { obj1, hit1 } => {
+                let (o1, h1) = (*obj1, *hit1);
+                self.step = StepTTR::Radius {
+                    obj1: o1,
+                    obj2: obj,
+                    hit1: h1,
+                    hit2: hit,
+                };
+                CmdResult::NeedPoint
+            }
+            StepTTR::Radius { .. } => CmdResult::NeedPoint,
+        }
+    }
+
+    fn on_text_input(&mut self, text: &str) -> Option<CmdResult> {
+        let r: f32 = text.trim().parse().ok()?;
+        if r <= 0.0 {
+            return Some(CmdResult::Cancel);
+        }
+        if let StepTTR::Radius {
+            obj1,
+            obj2,
+            hit1,
+            hit2,
+        } = &self.step
+        {
+            let hint = (*hit1 + *hit2) * 0.5;
+            let candidates = ttr_candidates(*obj1, *obj2, r);
+            if let Some(center) = best_of(&candidates, hint) {
+                Some(CmdResult::CommitAndExit(make_circle(center, r as f64)))
+            } else {
+                Some(CmdResult::Cancel)
+            }
+        } else {
+            None
+        }
+    }
+
+    fn on_enter(&mut self) -> CmdResult {
+        CmdResult::Cancel
+    }
+    fn on_escape(&mut self) -> CmdResult {
+        CmdResult::Cancel
+    }
+    fn on_mouse_move(&mut self, _pt: Vec3) -> Option<WireModel> {
+        None
+    }
+}
+
+// ── Command: Tan, Tan, Tan ────────────────────────────────────────────────
+
+pub struct CircleTTTCommand {
+    objs: Vec<TangentObject>,
+    hits: Vec<Vec3>,
+}
+
+impl CircleTTTCommand {
+    pub fn new() -> Self {
+        Self {
+            objs: Vec::new(),
+            hits: Vec::new(),
+        }
+    }
+}
+
+impl CadCommand for CircleTTTCommand {
+    fn name(&self) -> &'static str {
+        "CIRCLE_TTT"
+    }
+
+    fn needs_tangent_pick(&self) -> bool {
+        self.objs.len() < 3
+    }
+
+    fn prompt(&self) -> String {
+        match self.objs.len() {
+            0 => "CIRCLE TTT  Select first tangent object:".into(),
+            1 => "CIRCLE TTT  Select second tangent object:".into(),
+            _ => "CIRCLE TTT  Select third tangent object:".into(),
+        }
+    }
+
+    fn on_point(&mut self, _pt: Vec3) -> CmdResult {
+        CmdResult::NeedPoint
+    }
+
+    fn on_tangent_point(&mut self, obj: TangentObject, hit: Vec3) -> CmdResult {
+        self.objs.push(obj);
+        self.hits.push(hit);
+        if self.objs.len() < 3 {
+            return CmdResult::NeedPoint;
+        }
+        let hint = self.hits.iter().fold(Vec3::ZERO, |a, &b| a + b) / 3.0;
+        let candidates = ttt_candidates(self.objs[0], self.objs[1], self.objs[2]);
+        match best_circle_of(&candidates, hint) {
+            Some((center, r)) => CmdResult::CommitAndExit(make_circle(center, r as f64)),
+            None => {
+                self.objs.pop();
+                self.hits.pop();
+                CmdResult::NeedPoint
+            }
+        }
+    }
+
+    fn on_enter(&mut self) -> CmdResult {
+        CmdResult::Cancel
+    }
+    fn on_escape(&mut self) -> CmdResult {
+        CmdResult::Cancel
+    }
+    fn on_mouse_move(&mut self, _pt: Vec3) -> Option<WireModel> {
+        None
+    }
+}

src/modules/home/draw/ellipse.rs

@@ -0,0 +1,529 @@
+// Ellipse tool — ribbon dropdown + all H7CAD ellipse creation methods.
+//
+// Commands:
+//   ELLIPSE      — Center, Axes  (center → major endpoint → minor distance)
+//   ELLIPSE_AXIS — Axis, End     (axis endpoint 1 → endpoint 2 → minor distance)
+//   ELLIPSE_ARC  — Ellipse Arc   (shape as above, then start/end parametric angles)
+
+use acadrust::types::Vector3;
+use acadrust::{Ellipse, EntityType};
+
+use crate::command::{CadCommand, CmdResult};
+use crate::modules::IconKind;
+use crate::scene::wire_model::WireModel;
+use glam::Vec3;
+
+fn parse_f32(text: &str) -> Option<f32> {
+    text.trim().replace(',', ".").parse().ok()
+}
+
+const TAU: f32 = std::f32::consts::TAU;
+
+// ── Icons ─────────────────────────────────────────────────────────────────
+
+const ICON_CTR: IconKind = IconKind::Svg(include_bytes!(
+    "../../../../assets/icons/ellipse/ellipse_ctr.svg"
+));
+const ICON_AXIS: IconKind = IconKind::Svg(include_bytes!(
+    "../../../../assets/icons/ellipse/ellipse_axis.svg"
+));
+const ICON_ARC: IconKind = IconKind::Svg(include_bytes!(
+    "../../../../assets/icons/ellipse/ellipse_arc.svg"
+));
+
+// ── Dropdown metadata ─────────────────────────────────────────────────────
+
+pub const DROPDOWN_ID: &str = "ELLIPSE";
+
+pub const DROPDOWN_ITEMS: &[(&str, &str, IconKind)] = &[
+    ("ELLIPSE", "Center, Axes", ICON_CTR),
+    ("ELLIPSE_AXIS", "Axis, End", ICON_AXIS),
+    ("ELLIPSE_ARC", "Ellipse Arc", ICON_ARC),
+];
+
+pub const ICON: IconKind = ICON_CTR;
+
+// ── Shared helpers ────────────────────────────────────────────────────────
+
+/// Preview wire for a full or partial ellipse.
+fn ellipse_wire(
+    center: Vec3,
+    major: Vec3, // vector from center to major-axis endpoint
+    ratio: f32,  // minor/major
+    t_start: f32,
+    t_end: f32,
+) -> WireModel {
+    let r_major = major.length();
+    if r_major < 1e-9 {
+        return WireModel::solid("rubber_band".into(), vec![], WireModel::CYAN, false);
+    }
+    let major_dir = major / r_major;
+    let v = major_dir.cross(Vec3::Z).normalize();
+    let segs = 64u32;
+    // Unwrap t_end so the arc goes counter-clockwise.
+    let t_e = if t_end <= t_start { t_end + TAU } else { t_end };
+    let pts: Vec<[f32; 3]> = (0..=segs)
+        .map(|i| {
+            let t = t_start + (t_e - t_start) * (i as f32 / segs as f32);
+            let p = center + t.cos() * r_major * major_dir + t.sin() * r_major * ratio * v;
+            [p.x, p.y, p.z]
+        })
+        .collect();
+    WireModel::solid("rubber_band".into(), pts, WireModel::CYAN, false)
+}
+
+/// Convert a world point to the parametric angle on the ellipse.
+fn param_angle(center: Vec3, major_dir: Vec3, v: Vec3, pt: Vec3, ratio: f32) -> f32 {
+    let d = pt - center;
+    let u_proj = d.dot(major_dir);
+    let v_proj = d.dot(v);
+    // Inverse-map: on ellipse x=cos(t)*r_major, y=sin(t)*r_major*ratio
+    // → t = atan2(v_proj / (r_major*ratio), u_proj / r_major) but we normalise
+    v_proj.atan2(u_proj * ratio).rem_euclid(TAU)
+}
+
+/// Build the final Ellipse entity.
+fn make_ellipse(center: Vec3, major: Vec3, ratio: f32, t_start: f32, t_end: f32) -> Ellipse {
+    Ellipse {
+        center: Vector3::new(center.x as f64, center.y as f64, center.z as f64),
+        major_axis: Vector3::new(major.x as f64, major.y as f64, major.z as f64),
+        minor_axis_ratio: ratio as f64,
+        start_parameter: t_start as f64,
+        end_parameter: t_end as f64,
+        ..Default::default()
+    }
+}
+
+// ── 1. Center mode ────────────────────────────────────────────────────────
+//   Step 1: center   Step 2: major-axis endpoint   Step 3: minor-axis point
+
+enum CtrStep {
+    Center,
+    MajorAxis { center: Vec3 },
+    MinorRatio { center: Vec3, major: Vec3 },
+}
+
+pub struct EllipseCommand {
+    step: CtrStep,
+}
+
+impl EllipseCommand {
+    pub fn new() -> Self {
+        Self {
+            step: CtrStep::Center,
+        }
+    }
+}
+
+impl CadCommand for EllipseCommand {
+    fn name(&self) -> &'static str {
+        "ELLIPSE"
+    }
+
+    fn prompt(&self) -> String {
+        match &self.step {
+            CtrStep::Center => "ELLIPSE  Specify center:".into(),
+            CtrStep::MajorAxis { .. } => "ELLIPSE  Specify major axis endpoint:".into(),
+            CtrStep::MinorRatio { major, .. } => format!(
+                "ELLIPSE  Specify minor axis point or type half-length  [major r={:.3}]:",
+                major.length()
+            ),
+        }
+    }
+
+    fn on_point(&mut self, pt: Vec3) -> CmdResult {
+        match &self.step {
+            CtrStep::Center => {
+                self.step = CtrStep::MajorAxis { center: pt };
+                CmdResult::NeedPoint
+            }
+            CtrStep::MajorAxis { center } => {
+                let center = *center;
+                self.step = CtrStep::MinorRatio {
+                    center,
+                    major: pt - center,
+                };
+                CmdResult::NeedPoint
+            }
+            CtrStep::MinorRatio { center, major } => {
+                let (center, major) = (*center, *major);
+                let ratio = minor_ratio(center, major, pt);
+                CmdResult::CommitAndExit(EntityType::Ellipse(make_ellipse(
+                    center, major, ratio, 0.0, TAU,
+                )))
+            }
+        }
+    }
+
+    fn on_enter(&mut self) -> CmdResult {
+        CmdResult::Cancel
+    }
+
+    fn on_text_input(&mut self, text: &str) -> Option<CmdResult> {
+        if let CtrStep::MinorRatio { center, major } = &self.step {
+            let r_minor = parse_f32(text)?;
+            if r_minor > 0.0 {
+                let ratio = (r_minor / major.length()).clamp(1e-6, 1.0);
+                return Some(CmdResult::CommitAndExit(EntityType::Ellipse(make_ellipse(
+                    *center, *major, ratio, 0.0, TAU,
+                ))));
+            }
+        }
+        None
+    }
+
+    fn on_mouse_move(&mut self, pt: Vec3) -> Option<WireModel> {
+        match &self.step {
+            CtrStep::MajorAxis { center } => Some(line_wire(*center, pt)),
+            CtrStep::MinorRatio { center, major } => {
+                let ratio = minor_ratio(*center, *major, pt).max(0.001);
+                Some(ellipse_wire(*center, *major, ratio, 0.0, TAU))
+            }
+            _ => None,
+        }
+    }
+}
+
+// ── 2. Axis, End mode ─────────────────────────────────────────────────────
+//   Step 1: axis endpoint 1   Step 2: axis endpoint 2   Step 3: minor-axis point
+
+enum AxisStep {
+    Pt1,
+    Pt2 { p1: Vec3 },
+    MinorRatio { center: Vec3, major: Vec3 },
+}
+
+pub struct EllipseAxisCommand {
+    step: AxisStep,
+}
+
+impl EllipseAxisCommand {
+    pub fn new() -> Self {
+        Self {
+            step: AxisStep::Pt1,
+        }
+    }
+}
+
+impl CadCommand for EllipseAxisCommand {
+    fn name(&self) -> &'static str {
+        "ELLIPSE_AXIS"
+    }
+
+    fn prompt(&self) -> String {
+        match &self.step {
+            AxisStep::Pt1 => "ELLIPSE (Axis)  Specify first endpoint of major axis:".into(),
+            AxisStep::Pt2 { .. } => "ELLIPSE (Axis)  Specify second endpoint of major axis:".into(),
+            AxisStep::MinorRatio { major, .. } => format!(
+                "ELLIPSE (Axis)  Specify minor axis point or type half-length  [major r={:.3}]:",
+                major.length()
+            ),
+        }
+    }
+
+    fn on_point(&mut self, pt: Vec3) -> CmdResult {
+        match &self.step {
+            AxisStep::Pt1 => {
+                self.step = AxisStep::Pt2 { p1: pt };
+                CmdResult::NeedPoint
+            }
+            AxisStep::Pt2 { p1 } => {
+                let center = (*p1 + pt) * 0.5;
+                let major = pt - center; // half-vector
+                self.step = AxisStep::MinorRatio { center, major };
+                CmdResult::NeedPoint
+            }
+            AxisStep::MinorRatio { center, major } => {
+                let (center, major) = (*center, *major);
+                let ratio = minor_ratio(center, major, pt);
+                CmdResult::CommitAndExit(EntityType::Ellipse(make_ellipse(
+                    center, major, ratio, 0.0, TAU,
+                )))
+            }
+        }
+    }
+
+    fn on_enter(&mut self) -> CmdResult {
+        CmdResult::Cancel
+    }
+
+    fn on_text_input(&mut self, text: &str) -> Option<CmdResult> {
+        if let AxisStep::MinorRatio { center, major } = &self.step {
+            let r_minor = parse_f32(text)?;
+            if r_minor > 0.0 {
+                let ratio = (r_minor / major.length()).clamp(1e-6, 1.0);
+                return Some(CmdResult::CommitAndExit(EntityType::Ellipse(make_ellipse(
+                    *center, *major, ratio, 0.0, TAU,
+                ))));
+            }
+        }
+        None
+    }
+
+    fn on_mouse_move(&mut self, pt: Vec3) -> Option<WireModel> {
+        match &self.step {
+            AxisStep::Pt1 => None,
+            AxisStep::Pt2 { p1 } => Some(line_wire(*p1, pt)),
+            AxisStep::MinorRatio { center, major } => {
+                let ratio = minor_ratio(*center, *major, pt).max(0.001);
+                Some(ellipse_wire(*center, *major, ratio, 0.0, TAU))
+            }
+        }
+    }
+}
+
+// ── 3. Ellipse Arc mode ───────────────────────────────────────────────────
+//   Same shape steps as Center mode, then: start parameter, end parameter.
+
+enum ArcStep {
+    Center,
+    MajorAxis {
+        center: Vec3,
+    },
+    MinorRatio {
+        center: Vec3,
+        major: Vec3,
+    },
+    StartAngle {
+        center: Vec3,
+        major: Vec3,
+        ratio: f32,
+    },
+    EndAngle {
+        center: Vec3,
+        major: Vec3,
+        ratio: f32,
+        t_start: f32,
+    },
+}
+
+pub struct EllipseArcCommand {
+    step: ArcStep,
+    prev_pt: Option<Vec3>,
+    cw: bool,
+}
+
+impl EllipseArcCommand {
+    pub fn new() -> Self {
+        Self {
+            step: ArcStep::Center,
+            prev_pt: None,
+            cw: false,
+        }
+    }
+}
+
+impl CadCommand for EllipseArcCommand {
+    fn name(&self) -> &'static str {
+        "ELLIPSE_ARC"
+    }
+
+    fn prompt(&self) -> String {
+        match &self.step {
+            ArcStep::Center => "ELLIPSE ARC  Specify center:".into(),
+            ArcStep::MajorAxis { .. } => "ELLIPSE ARC  Specify major axis endpoint:".into(),
+            ArcStep::MinorRatio { major, .. } => format!(
+                "ELLIPSE ARC  Specify minor axis point or type half-length  [major r={:.3}]:",
+                major.length()
+            ),
+            ArcStep::StartAngle { .. } => {
+                "ELLIPSE ARC  Specify start angle point or type degrees:".into()
+            }
+            ArcStep::EndAngle { t_start, .. } => format!(
+                "ELLIPSE ARC  Specify end angle point or type degrees  [start={:.1}°]:",
+                t_start.to_degrees()
+            ),
+        }
+    }
+
+    fn on_point(&mut self, pt: Vec3) -> CmdResult {
+        match &self.step {
+            ArcStep::Center => {
+                self.step = ArcStep::MajorAxis { center: pt };
+                CmdResult::NeedPoint
+            }
+            ArcStep::MajorAxis { center } => {
+                let center = *center;
+                self.step = ArcStep::MinorRatio {
+                    center,
+                    major: pt - center,
+                };
+                CmdResult::NeedPoint
+            }
+            ArcStep::MinorRatio { center, major } => {
+                let (center, major) = (*center, *major);
+                let ratio = minor_ratio(center, major, pt);
+                self.step = ArcStep::StartAngle {
+                    center,
+                    major,
+                    ratio,
+                };
+                CmdResult::NeedPoint
+            }
+            ArcStep::StartAngle {
+                center,
+                major,
+                ratio,
+            } => {
+                let (center, major, ratio) = (*center, *major, *ratio);
+                let t_start = angle_from_point(center, major, ratio, pt);
+                self.prev_pt = None; // reset direction tracking for end-angle step
+                self.step = ArcStep::EndAngle {
+                    center,
+                    major,
+                    ratio,
+                    t_start,
+                };
+                CmdResult::NeedPoint
+            }
+            ArcStep::EndAngle {
+                center,
+                major,
+                ratio,
+                t_start,
+            } => {
+                let (center, major, ratio, t_start) = (*center, *major, *ratio, *t_start);
+                let t_end = angle_from_point(center, major, ratio, pt);
+                let entity = if self.cw {
+                    make_ellipse(center, major, ratio, t_end, t_start)
+                } else {
+                    make_ellipse(center, major, ratio, t_start, t_end)
+                };
+                CmdResult::CommitAndExit(EntityType::Ellipse(entity))
+            }
+        }
+    }
+
+    fn on_enter(&mut self) -> CmdResult {
+        CmdResult::Cancel
+    }
+
+    fn on_text_input(&mut self, text: &str) -> Option<CmdResult> {
+        let val = parse_f32(text)?;
+        match &self.step {
+            ArcStep::MinorRatio { center, major } => {
+                if val > 0.0 {
+                    let ratio = (val / major.length()).clamp(1e-6, 1.0);
+                    let (c, m) = (*center, *major);
+                    self.step = ArcStep::StartAngle {
+                        center: c,
+                        major: m,
+                        ratio,
+                    };
+                    return Some(CmdResult::NeedPoint);
+                }
+            }
+            ArcStep::StartAngle {
+                center,
+                major,
+                ratio,
+            } => {
+                let t_start = val.to_radians();
+                let (c, m, r) = (*center, *major, *ratio);
+                self.prev_pt = None;
+                self.step = ArcStep::EndAngle {
+                    center: c,
+                    major: m,
+                    ratio: r,
+                    t_start,
+                };
+                return Some(CmdResult::NeedPoint);
+            }
+            ArcStep::EndAngle {
+                center,
+                major,
+                ratio,
+                t_start,
+            } => {
+                // Typed degrees: positive = CCW, negative = CW.
+                let t_end = val.to_radians();
+                return Some(CmdResult::CommitAndExit(EntityType::Ellipse(make_ellipse(
+                    *center, *major, *ratio, *t_start, t_end,
+                ))));
+            }
+            _ => {}
+        }
+        None
+    }
+
+    fn on_mouse_move(&mut self, pt: Vec3) -> Option<WireModel> {
+        match &self.step {
+            ArcStep::MajorAxis { center } => Some(line_wire(*center, pt)),
+            ArcStep::MinorRatio { center, major } => {
+                let ratio = minor_ratio(*center, *major, pt).max(0.001);
+                Some(ellipse_wire(*center, *major, ratio, 0.0, TAU))
+            }
+            ArcStep::StartAngle {
+                center,
+                major,
+                ratio,
+            } => {
+                let t = angle_from_point(*center, *major, *ratio, pt);
+                Some(ellipse_wire(*center, *major, *ratio, 0.0, t))
+            }
+            ArcStep::EndAngle {
+                center,
+                major,
+                ratio,
+                t_start,
+            } => {
+                // Detect rotation direction via cross product.
+                if let Some(prev) = self.prev_pt {
+                    let p = prev - *center;
+                    let c = pt - *center;
+                    let sign = p.x * c.y - p.y * c.x;
+                    if sign.abs() > 1e-6 {
+                        self.cw = sign < 0.0;
+                    }
+                }
+                self.prev_pt = Some(pt);
+                let t_end = angle_from_point(*center, *major, *ratio, pt);
+                Some(if self.cw {
+                    ellipse_wire(*center, *major, *ratio, t_end, *t_start)
+                } else {
+                    ellipse_wire(*center, *major, *ratio, *t_start, t_end)
+                })
+            }
+            _ => None,
+        }
+    }
+}
+
+// ── Internal helpers ──────────────────────────────────────────────────────
+
+fn minor_ratio(center: Vec3, major: Vec3, pt: Vec3) -> f32 {
+    let r_major = major.length();
+    if r_major < 1e-9 {
+        return 0.5;
+    }
+    let major_dir = major / r_major;
+    let to_pt = pt - center;
+    let perp = to_pt - major_dir * to_pt.dot(major_dir);
+    let r_minor = perp.length().max(1e-6);
+    (r_minor / r_major).clamp(1e-6, 1.0)
+}
+
+fn angle_from_point(center: Vec3, major: Vec3, ratio: f32, pt: Vec3) -> f32 {
+    let r_major = major.length();
+    if r_major < 1e-9 {
+        return 0.0;
+    }
+    let major_dir = major / r_major;
+    let v = major_dir.cross(Vec3::Z).normalize();
+    param_angle(center, major_dir, v, pt, ratio)
+}
+
+fn line_wire(from: Vec3, to: Vec3) -> WireModel {
+    WireModel {
+        name: "rubber_band".into(),
+        points: vec![[from.x, from.y, from.z], [to.x, to.y, to.z]],
+        color: WireModel::CYAN,
+        selected: false,
+        pattern_length: 0.0,
+        pattern: [0.0; 8],
+        line_weight_px: 1.0,
+        snap_pts: vec![],
+        tangent_geoms: vec![],
+        key_vertices: vec![],
+    }
+}

src/modules/home/draw/hatch.rs

@@ -0,0 +1,419 @@
+// Hatch/Gradient/Boundary commands — H7CAD Home > Draw > Hatch dropdown.
+//
+// Commands:
+//   HATCH    — ANSI31: 45° hatch lines (pick inside or type S for manual)
+//   GRADIENT — Linear gradient fill (pick inside or type S for manual)
+//   BOUNDARY — Traces the enclosing boundary as a closed LwPolyline
+//
+// Primary workflow (matches H7CAD):
+//   Click a point INSIDE a closed region → boundary auto-detected.
+//   Type "S" to switch to manual vertex-picking mode (HATCH/GRADIENT only).
+
+use crate::command::{CadCommand, CmdResult};
+use crate::modules::IconKind;
+use crate::scene::hatch_model::{HatchModel, HatchPattern, PatFamily};
+use crate::scene::wire_model::WireModel;
+use glam::Vec3;
+
+// ── Icons ──────────────────────────────────────────────────────────────────
+
+const ICON_HATCH: IconKind = IconKind::Svg(include_bytes!(
+    "../../../../assets/icons/hatch/hatch_lines.svg"
+));
+const ICON_GRADIENT: IconKind = IconKind::Svg(include_bytes!(
+    "../../../../assets/icons/hatch/hatch_gradient.svg"
+));
+const ICON_BOUNDARY: IconKind = IconKind::Svg(include_bytes!(
+    "../../../../assets/icons/hatch/hatch_boundary.svg"
+));
+
+// ── Dropdown metadata ──────────────────────────────────────────────────────
+
+pub const DROPDOWN_ID: &str = "HATCH";
+pub const ICON: IconKind = ICON_HATCH;
+
+pub const DROPDOWN_ITEMS: &[(&str, &str, IconKind)] = &[
+    ("HATCH", "Hatch", ICON_HATCH),
+    ("GRADIENT", "Gradient", ICON_GRADIENT),
+    ("BOUNDARY", "Boundary", ICON_BOUNDARY),
+];
+
+// ── Shared mode ────────────────────────────────────────────────────────────
+
+enum Mode {
+    /// Primary: click inside a closed shape → boundary auto-detected.
+    PickInside,
+    /// Fallback: user manually picks polygon vertices (type "S" to enter).
+    Manual,
+}
+
+// ── CPU point-in-polygon (ray casting) ────────────────────────────────────
+
+fn point_in_polygon(p: [f32; 2], poly: &[[f32; 2]]) -> bool {
+    let n = poly.len();
+    if n < 3 {
+        return false;
+    }
+    let mut inside = false;
+    let mut j = n - 1;
+    for i in 0..n {
+        let vi = poly[i];
+        let vj = poly[j];
+        if (vi[1] > p[1]) != (vj[1] > p[1]) {
+            let x_int = (vj[0] - vi[0]) * (p[1] - vi[1]) / (vj[1] - vi[1]) + vi[0];
+            if p[0] < x_int {
+                inside = !inside;
+            }
+        }
+        j = i;
+    }
+    inside
+}
+
+// ── HATCH command ──────────────────────────────────────────────────────────
+
+pub struct HatchCommand {
+    outlines: Vec<Vec<[f32; 2]>>,
+    mode: Mode,
+    manual_pts: Vec<Vec3>,
+    missed: bool,
+}
+
+impl HatchCommand {
+    pub fn new(outlines: Vec<Vec<[f32; 2]>>) -> Self {
+        Self {
+            outlines,
+            mode: Mode::PickInside,
+            manual_pts: vec![],
+            missed: false,
+        }
+    }
+
+    fn make_hatch(&self, boundary: Vec<[f32; 2]>) -> HatchModel {
+        // Default: ANSI31 from catalog; fallback to a single 45° family.
+        let pat_name = "ANSI31";
+        let families = crate::scene::hatch_patterns::find(pat_name)
+            .and_then(|e| {
+                if let HatchPattern::Pattern(f) = &e.gpu {
+                    Some(f.clone())
+                } else {
+                    None
+                }
+            })
+            .unwrap_or_else(|| {
+                // 45° lines, perpendicular spacing ≈ 5 world units.
+                let dy = 5.0_f32 / (45.0_f32.to_radians().cos());
+                vec![PatFamily {
+                    angle_deg: 45.0,
+                    x0: 0.0,
+                    y0: 0.0,
+                    dx: 0.0,
+                    dy,
+                    dashes: vec![],
+                }]
+            });
+        HatchModel {
+            boundary,
+            pattern: HatchPattern::Pattern(families),
+            name: pat_name.into(),
+            color: [0.75, 0.75, 0.75, 0.85],
+            angle_offset: 0.0,
+            scale: 1.0,
+        }
+    }
+}
+
+impl CadCommand for HatchCommand {
+    fn name(&self) -> &'static str {
+        "HATCH"
+    }
+
+    fn prompt(&self) -> String {
+        match &self.mode {
+            Mode::PickInside => {
+                let miss = if self.missed {
+                    "  ⚠ Kapalı sınır bulunamadı."
+                } else {
+                    ""
+                };
+                format!("HATCH  İçini tıklayın [S=Elle çiz]:{miss}")
+            }
+            Mode::Manual => {
+                if self.manual_pts.is_empty() {
+                    "HATCH  Sınır noktası 1:".into()
+                } else {
+                    format!(
+                        "HATCH  Nokta {} [Enter=onayla, ≥3 nokta]:",
+                        self.manual_pts.len() + 1
+                    )
+                }
+            }
+        }
+    }
+
+    fn on_point(&mut self, pt: Vec3) -> CmdResult {
+        match &self.mode {
+            Mode::PickInside => {
+                let xy = [pt.x, pt.y];
+                for outline in &self.outlines {
+                    if point_in_polygon(xy, outline) {
+                        self.missed = false;
+                        return CmdResult::CommitHatch(self.make_hatch(outline.clone()));
+                    }
+                }
+                self.missed = true;
+                CmdResult::NeedPoint
+            }
+            Mode::Manual => {
+                self.manual_pts.push(pt);
+                CmdResult::NeedPoint
+            }
+        }
+    }
+
+    fn on_enter(&mut self) -> CmdResult {
+        match &self.mode {
+            Mode::PickInside => CmdResult::Cancel,
+            Mode::Manual => {
+                if self.manual_pts.len() < 3 {
+                    return CmdResult::Cancel;
+                }
+                let boundary = self.manual_pts.iter().map(|p| [p.x, p.y]).collect();
+                CmdResult::CommitHatch(self.make_hatch(boundary))
+            }
+        }
+    }
+
+    fn on_escape(&mut self) -> CmdResult {
+        CmdResult::Cancel
+    }
+
+    fn wants_text_input(&self) -> bool {
+        matches!(self.mode, Mode::PickInside)
+    }
+
+    fn on_text_input(&mut self, text: &str) -> Option<CmdResult> {
+        if text.trim().eq_ignore_ascii_case("s") {
+            self.mode = Mode::Manual;
+            self.missed = false;
+            return Some(CmdResult::NeedPoint);
+        }
+        None
+    }
+
+    fn on_mouse_move(&mut self, pt: Vec3) -> Option<WireModel> {
+        if let Mode::Manual = &self.mode {
+            if self.manual_pts.is_empty() {
+                return None;
+            }
+            let mut pts: Vec<[f32; 3]> = self.manual_pts.iter().map(|p| [p.x, p.y, p.z]).collect();
+            pts.push([pt.x, pt.y, pt.z]);
+            pts.push([
+                self.manual_pts[0].x,
+                self.manual_pts[0].y,
+                self.manual_pts[0].z,
+            ]);
+            return Some(WireModel::solid(
+                "rubber_band".into(),
+                pts,
+                WireModel::CYAN,
+                false,
+            ));
+        }
+        None
+    }
+}
+
+// ── GRADIENT command ───────────────────────────────────────────────────────
+
+pub struct GradientCommand {
+    outlines: Vec<Vec<[f32; 2]>>,
+    mode: Mode,
+    manual_pts: Vec<Vec3>,
+    missed: bool,
+}
+
+impl GradientCommand {
+    pub fn new(outlines: Vec<Vec<[f32; 2]>>) -> Self {
+        Self {
+            outlines,
+            mode: Mode::PickInside,
+            manual_pts: vec![],
+            missed: false,
+        }
+    }
+
+    fn make_hatch(&self, boundary: Vec<[f32; 2]>) -> HatchModel {
+        HatchModel {
+            boundary,
+            pattern: HatchPattern::Gradient {
+                angle_deg: 0.0,
+                color2: [0.18, 0.18, 0.18, 0.0],
+            },
+            name: "LINEAR".into(),
+            color: [0.30, 0.60, 0.95, 0.80],
+            angle_offset: 0.0,
+            scale: 1.0,
+        }
+    }
+}
+
+impl CadCommand for GradientCommand {
+    fn name(&self) -> &'static str {
+        "GRADIENT"
+    }
+
+    fn prompt(&self) -> String {
+        match &self.mode {
+            Mode::PickInside => {
+                let miss = if self.missed {
+                    "  ⚠ Kapalı sınır bulunamadı."
+                } else {
+                    ""
+                };
+                format!("GRADIENT  İçini tıklayın [S=Elle çiz]:{miss}")
+            }
+            Mode::Manual => {
+                if self.manual_pts.is_empty() {
+                    "GRADIENT  Sınır noktası 1:".into()
+                } else {
+                    format!(
+                        "GRADIENT  Nokta {} [Enter=onayla, ≥3 nokta]:",
+                        self.manual_pts.len() + 1
+                    )
+                }
+            }
+        }
+    }
+
+    fn on_point(&mut self, pt: Vec3) -> CmdResult {
+        match &self.mode {
+            Mode::PickInside => {
+                let xy = [pt.x, pt.y];
+                for outline in &self.outlines {
+                    if point_in_polygon(xy, outline) {
+                        self.missed = false;
+                        return CmdResult::CommitHatch(self.make_hatch(outline.clone()));
+                    }
+                }
+                self.missed = true;
+                CmdResult::NeedPoint
+            }
+            Mode::Manual => {
+                self.manual_pts.push(pt);
+                CmdResult::NeedPoint
+            }
+        }
+    }
+
+    fn on_enter(&mut self) -> CmdResult {
+        match &self.mode {
+            Mode::PickInside => CmdResult::Cancel,
+            Mode::Manual => {
+                if self.manual_pts.len() < 3 {
+                    return CmdResult::Cancel;
+                }
+                let boundary = self.manual_pts.iter().map(|p| [p.x, p.y]).collect();
+                CmdResult::CommitHatch(self.make_hatch(boundary))
+            }
+        }
+    }
+
+    fn on_escape(&mut self) -> CmdResult {
+        CmdResult::Cancel
+    }
+
+    fn wants_text_input(&self) -> bool {
+        matches!(self.mode, Mode::PickInside)
+    }
+
+    fn on_text_input(&mut self, text: &str) -> Option<CmdResult> {
+        if text.trim().eq_ignore_ascii_case("s") {
+            self.mode = Mode::Manual;
+            self.missed = false;
+            return Some(CmdResult::NeedPoint);
+        }
+        None
+    }
+
+    fn on_mouse_move(&mut self, pt: Vec3) -> Option<WireModel> {
+        if let Mode::Manual = &self.mode {
+            if self.manual_pts.is_empty() {
+                return None;
+            }
+            let mut pts: Vec<[f32; 3]> = self.manual_pts.iter().map(|p| [p.x, p.y, p.z]).collect();
+            pts.push([pt.x, pt.y, pt.z]);
+            pts.push([
+                self.manual_pts[0].x,
+                self.manual_pts[0].y,
+                self.manual_pts[0].z,
+            ]);
+            return Some(WireModel::solid(
+                "rubber_band".into(),
+                pts,
+                WireModel::CYAN,
+                false,
+            ));
+        }
+        None
+    }
+}
+
+// ── BOUNDARY command ───────────────────────────────────────────────────────
+
+pub struct BoundaryCommand {
+    outlines: Vec<Vec<[f32; 2]>>,
+    missed: bool,
+}
+
+impl BoundaryCommand {
+    pub fn new(outlines: Vec<Vec<[f32; 2]>>) -> Self {
+        Self {
+            outlines,
+            missed: false,
+        }
+    }
+}
+
+impl CadCommand for BoundaryCommand {
+    fn name(&self) -> &'static str {
+        "BOUNDARY"
+    }
+
+    fn prompt(&self) -> String {
+        let miss = if self.missed {
+            "  ⚠ Kapalı sınır bulunamadı."
+        } else {
+            ""
+        };
+        format!("BOUNDARY  İçini tıklayın:{miss}")
+    }
+
+    fn on_point(&mut self, pt: Vec3) -> CmdResult {
+        let xy = [pt.x, pt.y];
+        for outline in &self.outlines {
+            if point_in_polygon(xy, outline) {
+                self.missed = false;
+                // Store as a Hatch entity (solid fill) so it is selectable.
+                let model = HatchModel {
+                    boundary: outline.clone(),
+                    pattern: HatchPattern::Solid,
+                    name: "SOLID".into(),
+                    color: [0.45, 0.45, 0.45, 0.60],
+                    angle_offset: 0.0,
+                    scale: 1.0,
+                };
+                return CmdResult::CommitHatch(model);
+            }
+        }
+        self.missed = true;
+        CmdResult::NeedPoint
+    }
+
+    fn on_enter(&mut self) -> CmdResult {
+        CmdResult::Cancel
+    }
+    fn on_escape(&mut self) -> CmdResult {
+        CmdResult::Cancel
+    }
+}

src/modules/home/draw/line.rs

@@ -0,0 +1,91 @@
+// Line tool — ribbon definition + interactive command.
+//
+// Command:  LINE — H7CAD behaviour:
+//   1. First click  → stores start point, prompts for next point
+//   2. Each further click → immediately commits an acadrust::Line entity
+//      (start→end) to the document; end becomes the new start point
+//   3. Enter / Escape → ends the command
+
+use acadrust::types::Vector3;
+use acadrust::{EntityType, Line};
+
+use crate::command::{CadCommand, CmdResult};
+use crate::modules::{IconKind, ModuleEvent, ToolDef};
+use crate::scene::wire_model::WireModel;
+use glam::Vec3;
+
+// ── Ribbon definition ─────────────────────────────────────────────────────
+
+pub fn tool() -> ToolDef {
+    ToolDef {
+        id: "LINE",
+        label: "Line",
+        icon: IconKind::Svg(include_bytes!("../../../../assets/icons/line.svg")),
+        event: ModuleEvent::Command("LINE".to_string()),
+    }
+}
+
+// ── Command implementation ────────────────────────────────────────────────
+
+pub struct LineCommand {
+    /// The last committed point (start of the next segment).
+    last: Option<Vec3>,
+}
+
+impl LineCommand {
+    pub fn new() -> Self {
+        Self { last: None }
+    }
+}
+
+impl CadCommand for LineCommand {
+    fn name(&self) -> &'static str {
+        "LINE"
+    }
+
+    fn prompt(&self) -> String {
+        if self.last.is_none() {
+            "LINE  Specify first point:".to_string()
+        } else {
+            "LINE  Specify next point  [Enter/Esc = done]:".to_string()
+        }
+    }
+
+    fn on_point(&mut self, pt: Vec3) -> CmdResult {
+        if let Some(last) = self.last {
+            let line = Line::from_points(
+                Vector3::new(last.x as f64, last.y as f64, last.z as f64),
+                Vector3::new(pt.x as f64, pt.y as f64, pt.z as f64),
+            );
+            self.last = Some(pt);
+            CmdResult::CommitEntity(EntityType::Line(line))
+        } else {
+            self.last = Some(pt);
+            CmdResult::NeedPoint
+        }
+    }
+
+    fn on_enter(&mut self) -> CmdResult {
+        CmdResult::Cancel
+    }
+
+    fn on_escape(&mut self) -> CmdResult {
+        CmdResult::Cancel
+    }
+
+    fn on_mouse_move(&mut self, pt: Vec3) -> Option<WireModel> {
+        let last = self.last?;
+        Some(WireModel {
+            name: "rubber_band".to_string(),
+            points: vec![[last.x, last.y, last.z], [pt.x, pt.y, pt.z]],
+            color: WireModel::CYAN,
+            selected: false,
+            pattern_length: 0.0,
+            pattern: [0.0; 8],
+            line_weight_px: 1.0,
+            snap_pts: vec![],
+            tangent_geoms: vec![],
+            key_vertices: vec![],
+        })
+    }
+}

src/modules/home/draw/mod.rs

@@ -0,0 +1,9 @@
+pub mod arc;
+pub mod circle;
+pub mod ellipse;
+pub mod hatch;
+pub mod line;
+pub mod point;
+pub mod polyline;
+pub mod shapes;
+pub mod spline;

src/modules/home/draw/point.rs

@@ -0,0 +1,57 @@
+// Point tool — ribbon definition + interactive command.
+//
+// Command:  POINT (PO)
+//   Single click → commits EntityType::Point.  Stays active for more points.
+
+use acadrust::types::Vector3;
+use acadrust::{EntityType, Point as CadPoint};
+
+use crate::command::{CadCommand, CmdResult};
+use crate::modules::{IconKind, ModuleEvent, ToolDef};
+use crate::scene::wire_model::WireModel;
+use glam::Vec3;
+
+#[allow(dead_code)]
+pub fn tool() -> ToolDef {
+    ToolDef {
+        id: "POINT",
+        label: "Point",
+        icon: IconKind::Svg(include_bytes!("../../../../assets/icons/point.svg")),
+        event: ModuleEvent::Command("POINT".to_string()),
+    }
+}
+
+pub struct PointCommand;
+
+impl PointCommand {
+    pub fn new() -> Self {
+        Self
+    }
+}
+
+impl CadCommand for PointCommand {
+    fn name(&self) -> &'static str {
+        "POINT"
+    }
+    fn prompt(&self) -> String {
+        "POINT  Specify point  [Enter=done]:".into()
+    }
+
+    fn on_point(&mut self, pt: Vec3) -> CmdResult {
+        let p = CadPoint {
+            location: Vector3::new(pt.x as f64, pt.y as f64, pt.z as f64),
+            ..Default::default()
+        };
+        CmdResult::CommitEntity(EntityType::Point(p))
+    }
+
+    fn on_enter(&mut self) -> CmdResult {
+        CmdResult::Cancel
+    }
+    fn on_escape(&mut self) -> CmdResult {
+        CmdResult::Cancel
+    }
+    fn on_mouse_move(&mut self, _pt: Vec3) -> Option<WireModel> {
+        None
+    }
+}

src/modules/home/draw/polyline.rs

@@ -0,0 +1,106 @@
+// Polyline tool — ribbon definition + interactive command.
+//
+// Command:  PLINE (PL)
+//   Each click adds a vertex.  The rubber-band shows the segment being drawn.
+//   Enter / C = close and commit.  Escape = commit as-is (if ≥2 vertices).
+
+use acadrust::entities::LwVertex;
+use acadrust::{EntityType, LwPolyline};
+
+use crate::command::{CadCommand, CmdResult};
+use crate::modules::{IconKind, ModuleEvent, ToolDef};
+use crate::scene::wire_model::WireModel;
+use glam::Vec3;
+
+// ── Ribbon definition ──────────────────────────────────────────────────────
+
+pub fn tool() -> ToolDef {
+    ToolDef {
+        id: "PLINE",
+        label: "Polyline",
+        icon: IconKind::Svg(include_bytes!("../../../../assets/icons/polyline.svg")),
+        event: ModuleEvent::Command("PLINE".to_string()),
+    }
+}
+
+// ── Command implementation ─────────────────────────────────────────────────
+
+pub struct PlineCommand {
+    vertices: Vec<Vec3>,
+}
+
+impl PlineCommand {
+    pub fn new() -> Self {
+        Self {
+            vertices: Vec::new(),
+        }
+    }
+
+    fn build_entity(&self, closed: bool) -> Option<EntityType> {
+        if self.vertices.len() < 2 {
+            return None;
+        }
+        let lw_verts: Vec<LwVertex> = self
+            .vertices
+            .iter()
+            .map(|v| LwVertex::new(acadrust::types::Vector2::new(v.x as f64, v.y as f64)))
+            .collect();
+        let pline = LwPolyline {
+            vertices: lw_verts,
+            is_closed: closed,
+            ..Default::default()
+        };
+        Some(EntityType::LwPolyline(pline))
+    }
+}
+
+impl CadCommand for PlineCommand {
+    fn name(&self) -> &'static str {
+        "PLINE"
+    }
+
+    fn prompt(&self) -> String {
+        if self.vertices.is_empty() {
+            "PLINE  Specify start point:".into()
+        } else {
+            format!(
+                "PLINE  Specify next point  [{}pts | Enter=done C=close Esc=cancel]:",
+                self.vertices.len()
+            )
+        }
+    }
+
+    fn on_point(&mut self, pt: Vec3) -> CmdResult {
+        self.vertices.push(pt);
+        CmdResult::NeedPoint
+    }
+
+    fn on_enter(&mut self) -> CmdResult {
+        match self.build_entity(false) {
+            Some(e) => CmdResult::CommitAndExit(e),
+            None => CmdResult::Cancel,
+        }
+    }
+
+    fn on_escape(&mut self) -> CmdResult {
+        match self.build_entity(false) {
+            Some(e) => CmdResult::CommitAndExit(e),
+            None => CmdResult::Cancel,
+        }
+    }
+
+    fn on_mouse_move(&mut self, pt: Vec3) -> Option<WireModel> {
+        if self.vertices.is_empty() {
+            return None;
+        }
+        // Show all committed vertices + cursor as a continuous preview.
+        let mut pts: Vec<[f32; 3]> = self.vertices.iter().map(|v| [v.x, v.y, v.z]).collect();
+        pts.push([pt.x, pt.y, pt.z]);
+        Some(WireModel::solid(
+            "rubber_band".into(),
+            pts,
+            WireModel::CYAN,
+            false,
+        ))
+    }
+}

src/modules/home/draw/shapes.rs

@@ -0,0 +1,635 @@
+// Shapes dropdown — Rectangle and Polygon creation methods.
+//
+// Rectangle:
+//   RECT     — Two Corners (axis-aligned)
+//   RECT_ROT — Rotated (corner + adjacent corner + height)
+//   RECT_CEN — Center Point + corner
+//
+// Polygon (regular N-gon, sides typed in command line):
+//   POLY   — Inscribed in circle   (vertices ON the circle)
+//   POLY_C — Circumscribed about circle (edges tangent to circle)
+//   POLY_E — Edge (pick two endpoints of one edge)
+
+use acadrust::entities::LwVertex;
+use acadrust::types::Vector2;
+use acadrust::{EntityType, LwPolyline};
+
+use crate::command::{CadCommand, CmdResult};
+use crate::modules::IconKind;
+use crate::scene::wire_model::WireModel;
+use glam::Vec3;
+
+const TAU: f32 = std::f32::consts::TAU;
+const PI: f32 = std::f32::consts::PI;
+
+// ── Icons ──────────────────────────────────────────────────────────────────
+
+const ICON_RECT: IconKind =
+    IconKind::Svg(include_bytes!("../../../../assets/icons/shapes/rect.svg"));
+const ICON_RECT_ROT: IconKind = IconKind::Svg(include_bytes!(
+    "../../../../assets/icons/shapes/rect_rot.svg"
+));
+const ICON_RECT_CEN: IconKind = IconKind::Svg(include_bytes!(
+    "../../../../assets/icons/shapes/rect_cen.svg"
+));
+const ICON_POLY_I: IconKind =
+    IconKind::Svg(include_bytes!("../../../../assets/icons/shapes/poly_i.svg"));
+const ICON_POLY_C: IconKind =
+    IconKind::Svg(include_bytes!("../../../../assets/icons/shapes/poly_c.svg"));
+const ICON_POLY_E: IconKind =
+    IconKind::Svg(include_bytes!("../../../../assets/icons/shapes/poly_e.svg"));
+
+// ── Dropdown metadata ──────────────────────────────────────────────────────
+
+pub const DROPDOWN_ID: &str = "SHAPES";
+
+pub const DROPDOWN_ITEMS: &[(&str, &str, IconKind)] = &[
+    ("RECT", "Rectangle - Two Corners", ICON_RECT),
+    ("RECT_ROT", "Rectangle - Rotated", ICON_RECT_ROT),
+    ("RECT_CEN", "Rectangle - Center", ICON_RECT_CEN),
+    ("POLY", "Polygon - Inscribed", ICON_POLY_I),
+    ("POLY_C", "Polygon - Circumscribed", ICON_POLY_C),
+    ("POLY_E", "Polygon - Edge", ICON_POLY_E),
+];
+
+pub const ICON: IconKind = ICON_RECT;
+
+// ── Shared geometry helpers ────────────────────────────────────────────────
+
+fn make_pline(xy_pairs: &[[f64; 2]]) -> EntityType {
+    EntityType::LwPolyline(LwPolyline {
+        vertices: xy_pairs
+            .iter()
+            .map(|&[x, y]| LwVertex::new(Vector2::new(x, y)))
+            .collect(),
+        is_closed: true,
+        ..Default::default()
+    })
+}
+
+fn wire_loop(pts: Vec<[f32; 3]>) -> WireModel {
+    let mut p = pts;
+    if let Some(&first) = p.first() {
+        p.push(first);
+    }
+    WireModel::solid("rubber_band".into(), p, WireModel::CYAN, false)
+}
+
+fn wire_seg(a: Vec3, b: Vec3) -> WireModel {
+    WireModel::solid(
+        "rubber_band".into(),
+        vec![[a.x, a.y, a.z], [b.x, b.y, b.z]],
+        WireModel::CYAN,
+        false,
+    )
+}
+
+// ── Polygon geometry ───────────────────────────────────────────────────────
+
+fn poly_verts_xy(center: Vec3, vertex_r: f32, sides: u32, start_angle: f32) -> Vec<[f64; 2]> {
+    (0..sides)
+        .map(|i| {
+            let a = start_angle + (i as f32) * TAU / sides as f32;
+            [
+                (center.x + vertex_r * a.cos()) as f64,
+                (center.y + vertex_r * a.sin()) as f64,
+            ]
+        })
+        .collect()
+}
+
+fn poly_wire(center: Vec3, vertex_r: f32, sides: u32, start_angle: f32) -> WireModel {
+    let pts: Vec<[f32; 3]> = (0..sides)
+        .map(|i| {
+            let a = start_angle + (i as f32) * TAU / sides as f32;
+            [
+                center.x + vertex_r * a.cos(),
+                center.y + vertex_r * a.sin(),
+                center.z,
+            ]
+        })
+        .collect();
+    wire_loop(pts)
+}
+
+fn angle_xy(from: Vec3, to: Vec3) -> f32 {
+    (to.y - from.y).atan2(to.x - from.x)
+}
+
+// ── Command: Rectangle — Two Corners  (RECT) ──────────────────────────────
+
+pub struct RectCommand {
+    a: Option<Vec3>,
+}
+
+impl RectCommand {
+    pub fn new() -> Self {
+        Self { a: None }
+    }
+}
+
+impl CadCommand for RectCommand {
+    fn name(&self) -> &'static str {
+        "RECT"
+    }
+    fn prompt(&self) -> String {
+        if self.a.is_none() {
+            "RECT  Specify first corner:".into()
+        } else {
+            "RECT  Specify opposite corner:".into()
+        }
+    }
+    fn on_point(&mut self, pt: Vec3) -> CmdResult {
+        match self.a {
+            None => {
+                self.a = Some(pt);
+                CmdResult::NeedPoint
+            }
+            Some(a) => CmdResult::CommitAndExit(make_pline(&[
+                [a.x as f64, a.y as f64],
+                [pt.x as f64, a.y as f64],
+                [pt.x as f64, pt.y as f64],
+                [a.x as f64, pt.y as f64],
+            ])),
+        }
+    }
+    fn on_enter(&mut self) -> CmdResult {
+        CmdResult::Cancel
+    }
+    fn on_escape(&mut self) -> CmdResult {
+        CmdResult::Cancel
+    }
+    fn on_mouse_move(&mut self, pt: Vec3) -> Option<WireModel> {
+        let a = self.a?;
+        Some(wire_loop(vec![
+            [a.x, a.y, a.z],
+            [pt.x, a.y, a.z],
+            [pt.x, pt.y, a.z],
+            [a.x, pt.y, a.z],
+        ]))
+    }
+}
+
+// ── Command: Rectangle — Rotated  (RECT_ROT) ──────────────────────────────
+//   Step 0: pick corner A
+//   Step 1: pick adjacent corner B  (defines one edge direction + length)
+//   Step 2: pick height point  (perpendicular offset from the A-B edge)
+
+pub struct RectRotCommand {
+    step: u8,
+    a: Vec3,
+    b: Vec3,
+}
+
+impl RectRotCommand {
+    pub fn new() -> Self {
+        Self {
+            step: 0,
+            a: Vec3::ZERO,
+            b: Vec3::ZERO,
+        }
+    }
+}
+
+impl CadCommand for RectRotCommand {
+    fn name(&self) -> &'static str {
+        "RECT_ROT"
+    }
+    fn prompt(&self) -> String {
+        match self.step {
+            0 => "RECT ROT  Specify first corner:".into(),
+            1 => "RECT ROT  Specify adjacent corner (defines edge direction):".into(),
+            _ => "RECT ROT  Specify height (perpendicular pick):".into(),
+        }
+    }
+    fn on_point(&mut self, pt: Vec3) -> CmdResult {
+        match self.step {
+            0 => {
+                self.a = pt;
+                self.step = 1;
+                CmdResult::NeedPoint
+            }
+            1 => {
+                self.b = pt;
+                self.step = 2;
+                CmdResult::NeedPoint
+            }
+            _ => {
+                let (a, b) = (self.a, self.b);
+                let dir = (b - a).normalize_or_zero();
+                let perp = Vec3::new(-dir.y, dir.x, 0.0);
+                let h = (pt - b).dot(perp); // signed height
+                let c = b + perp * h;
+                let d = a + perp * h;
+                CmdResult::CommitAndExit(make_pline(&[
+                    [a.x as f64, a.y as f64],
+                    [b.x as f64, b.y as f64],
+                    [c.x as f64, c.y as f64],
+                    [d.x as f64, d.y as f64],
+                ]))
+            }
+        }
+    }
+    fn on_enter(&mut self) -> CmdResult {
+        CmdResult::Cancel
+    }
+    fn on_escape(&mut self) -> CmdResult {
+        CmdResult::Cancel
+    }
+    fn on_mouse_move(&mut self, pt: Vec3) -> Option<WireModel> {
+        match self.step {
+            1 => Some(wire_seg(self.a, pt)),
+            2 => {
+                let (a, b) = (self.a, self.b);
+                let dir = (b - a).normalize_or_zero();
+                let perp = Vec3::new(-dir.y, dir.x, 0.0);
+                let h = (pt - b).dot(perp);
+                let c = b + perp * h;
+                let d = a + perp * h;
+                Some(wire_loop(vec![
+                    [a.x, a.y, a.z],
+                    [b.x, b.y, b.z],
+                    [c.x, c.y, c.z],
+                    [d.x, d.y, d.z],
+                ]))
+            }
+            _ => None,
+        }
+    }
+}
+
+// ── Command: Rectangle — Center  (RECT_CEN) ───────────────────────────────
+//   Step 0: pick center
+//   Step 1: pick any corner  (half-width = |cx|, half-height = |cy|)
+
+pub struct RectCenCommand {
+    center: Option<Vec3>,
+}
+
+impl RectCenCommand {
+    pub fn new() -> Self {
+        Self { center: None }
+    }
+}
+
+impl CadCommand for RectCenCommand {
+    fn name(&self) -> &'static str {
+        "RECT_CEN"
+    }
+    fn prompt(&self) -> String {
+        if self.center.is_none() {
+            "RECT CEN  Specify center point:".into()
+        } else {
+            "RECT CEN  Specify corner point:".into()
+        }
+    }
+    fn on_point(&mut self, pt: Vec3) -> CmdResult {
+        match self.center {
+            None => {
+                self.center = Some(pt);
+                CmdResult::NeedPoint
+            }
+            Some(c) => {
+                let hw = (pt.x - c.x).abs() as f64;
+                let hh = (pt.y - c.y).abs() as f64;
+                let cx = c.x as f64;
+                let cy = c.y as f64;
+                CmdResult::CommitAndExit(make_pline(&[
+                    [cx - hw, cy - hh],
+                    [cx + hw, cy - hh],
+                    [cx + hw, cy + hh],
+                    [cx - hw, cy + hh],
+                ]))
+            }
+        }
+    }
+    fn on_enter(&mut self) -> CmdResult {
+        CmdResult::Cancel
+    }
+    fn on_escape(&mut self) -> CmdResult {
+        CmdResult::Cancel
+    }
+    fn on_mouse_move(&mut self, pt: Vec3) -> Option<WireModel> {
+        let c = self.center?;
+        let hw = (pt.x - c.x).abs();
+        let hh = (pt.y - c.y).abs();
+        Some(wire_loop(vec![
+            [c.x - hw, c.y - hh, c.z],
+            [c.x + hw, c.y - hh, c.z],
+            [c.x + hw, c.y + hh, c.z],
+            [c.x - hw, c.y + hh, c.z],
+        ]))
+    }
+}
+
+// ── Command: Polygon — Inscribed  (POLY) ──────────────────────────────────
+//   Type number of sides (default 6) → pick center → pick vertex
+//   Vertices lie ON the circle of the picked radius.
+
+pub struct PolyCommand {
+    sides: u32,
+    step: u8,
+    center: Vec3,
+}
+
+impl PolyCommand {
+    pub fn new() -> Self {
+        Self {
+            sides: 6,
+            step: 0,
+            center: Vec3::ZERO,
+        }
+    }
+}
+
+impl CadCommand for PolyCommand {
+    fn name(&self) -> &'static str {
+        "POLY"
+    }
+
+    fn wants_text_input(&self) -> bool {
+        self.step == 0
+    }
+
+    fn on_text_input(&mut self, text: &str) -> Option<CmdResult> {
+        if let Ok(n) = text.trim().parse::<u32>() {
+            if (3..=1024).contains(&n) {
+                self.sides = n;
+            }
+        }
+        self.step = 1;
+        Some(CmdResult::NeedPoint)
+    }
+
+    fn prompt(&self) -> String {
+        match self.step {
+            0 => format!("POLYGON  Enter number of sides <{}>:", self.sides),
+            1 => format!("POLYGON  Specify center [{} sides]:", self.sides),
+            _ => format!(
+                "POLYGON  Specify vertex on circle [{} sides inscribed]:",
+                self.sides
+            ),
+        }
+    }
+
+    fn on_point(&mut self, pt: Vec3) -> CmdResult {
+        match self.step {
+            0 => {
+                // User clicked without typing sides: use default, treat click as center.
+                self.center = pt;
+                self.step = 2;
+                CmdResult::NeedPoint
+            }
+            1 => {
+                self.center = pt;
+                self.step = 2;
+                CmdResult::NeedPoint
+            }
+            _ => {
+                let r = self.center.distance(pt);
+                let sa = angle_xy(self.center, pt);
+                CmdResult::CommitAndExit(make_pline(&poly_verts_xy(self.center, r, self.sides, sa)))
+            }
+        }
+    }
+
+    fn on_enter(&mut self) -> CmdResult {
+        if self.step == 0 {
+            self.step = 1;
+            return CmdResult::NeedPoint;
+        }
+        CmdResult::Cancel
+    }
+    fn on_escape(&mut self) -> CmdResult {
+        CmdResult::Cancel
+    }
+
+    fn on_mouse_move(&mut self, pt: Vec3) -> Option<WireModel> {
+        if self.step < 2 {
+            return None;
+        }
+        let r = self.center.distance(pt);
+        let sa = angle_xy(self.center, pt);
+        Some(poly_wire(self.center, r, self.sides, sa))
+    }
+}
+
+// ── Command: Polygon — Circumscribed  (POLY_C) ────────────────────────────
+//   Type sides → pick center → pick edge-midpoint (on the inscribed circle).
+//   vertex_radius = inradius / cos(π/N).
+
+pub struct PolyCCommand {
+    sides: u32,
+    step: u8,
+    center: Vec3,
+}
+
+impl PolyCCommand {
+    pub fn new() -> Self {
+        Self {
+            sides: 6,
+            step: 0,
+            center: Vec3::ZERO,
+        }
+    }
+}
+
+impl CadCommand for PolyCCommand {
+    fn name(&self) -> &'static str {
+        "POLY_C"
+    }
+
+    fn wants_text_input(&self) -> bool {
+        self.step == 0
+    }
+
+    fn on_text_input(&mut self, text: &str) -> Option<CmdResult> {
+        if let Ok(n) = text.trim().parse::<u32>() {
+            if (3..=1024).contains(&n) {
+                self.sides = n;
+            }
+        }
+        self.step = 1;
+        Some(CmdResult::NeedPoint)
+    }
+
+    fn prompt(&self) -> String {
+        match self.step {
+            0 => format!("POLYGON C  Enter number of sides <{}>:", self.sides),
+            1 => format!("POLYGON C  Specify center [{} sides]:", self.sides),
+            _ => format!(
+                "POLYGON C  Specify edge-midpoint radius [{} sides circumscribed]:",
+                self.sides
+            ),
+        }
+    }
+
+    fn on_point(&mut self, pt: Vec3) -> CmdResult {
+        match self.step {
+            0 => {
+                self.center = pt;
+                self.step = 2;
+                CmdResult::NeedPoint
+            }
+            1 => {
+                self.center = pt;
+                self.step = 2;
+                CmdResult::NeedPoint
+            }
+            _ => {
+                let inradius = self.center.distance(pt);
+                let vr = inradius / (PI / self.sides as f32).cos();
+                // The picked pt is at the midpoint of an edge; the vertex is
+                // offset by half a sector (π/N) from that direction.
+                let edge_angle = angle_xy(self.center, pt);
+                let sa = edge_angle + PI / self.sides as f32;
+                CmdResult::CommitAndExit(make_pline(&poly_verts_xy(
+                    self.center,
+                    vr,
+                    self.sides,
+                    sa,
+                )))
+            }
+        }
+    }
+
+    fn on_enter(&mut self) -> CmdResult {
+        if self.step == 0 {
+            self.step = 1;
+            return CmdResult::NeedPoint;
+        }
+        CmdResult::Cancel
+    }
+    fn on_escape(&mut self) -> CmdResult {
+        CmdResult::Cancel
+    }
+
+    fn on_mouse_move(&mut self, pt: Vec3) -> Option<WireModel> {
+        if self.step < 2 {
+            return None;
+        }
+        let inradius = self.center.distance(pt);
+        let vr = inradius / (PI / self.sides as f32).cos();
+        let sa = angle_xy(self.center, pt) + PI / self.sides as f32;
+        Some(poly_wire(self.center, vr, self.sides, sa))
+    }
+}
+
+// ── Command: Polygon — Edge  (POLY_E) ─────────────────────────────────────
+//   Type sides → pick edge start A → pick edge end B.
+//   Center is computed from the edge and the polygon geometry.
+
+pub struct PolyECommand {
+    sides: u32,
+    step: u8,
+    a: Vec3,
+}
+
+impl PolyECommand {
+    pub fn new() -> Self {
+        Self {
+            sides: 6,
+            step: 0,
+            a: Vec3::ZERO,
+        }
+    }
+}
+
+impl CadCommand for PolyECommand {
+    fn name(&self) -> &'static str {
+        "POLY_E"
+    }
+
+    fn wants_text_input(&self) -> bool {
+        self.step == 0
+    }
+
+    fn on_text_input(&mut self, text: &str) -> Option<CmdResult> {
+        if let Ok(n) = text.trim().parse::<u32>() {
+            if (3..=1024).contains(&n) {
+                self.sides = n;
+            }
+        }
+        self.step = 1;
+        Some(CmdResult::NeedPoint)
+    }
+
+    fn prompt(&self) -> String {
+        match self.step {
+            0 => format!("POLYGON E  Enter number of sides <{}>:", self.sides),
+            1 => format!(
+                "POLYGON E  Specify first endpoint of edge [{} sides]:",
+                self.sides
+            ),
+            _ => format!(
+                "POLYGON E  Specify second endpoint of edge [{} sides]:",
+                self.sides
+            ),
+        }
+    }
+
+    fn on_point(&mut self, pt: Vec3) -> CmdResult {
+        match self.step {
+            0 => {
+                self.a = pt;
+                self.step = 2;
+                CmdResult::NeedPoint
+            }
+            1 => {
+                self.a = pt;
+                self.step = 2;
+                CmdResult::NeedPoint
+            }
+            _ => {
+                if let Some((center, vr, sa)) = edge_poly_params(self.a, pt, self.sides) {
+                    CmdResult::CommitAndExit(make_pline(&poly_verts_xy(center, vr, self.sides, sa)))
+                } else {
+                    CmdResult::Cancel
+                }
+            }
+        }
+    }
+
+    fn on_enter(&mut self) -> CmdResult {
+        if self.step == 0 {
+            self.step = 1;
+            return CmdResult::NeedPoint;
+        }
+        CmdResult::Cancel
+    }
+    fn on_escape(&mut self) -> CmdResult {
+        CmdResult::Cancel
+    }
+
+    fn on_mouse_move(&mut self, pt: Vec3) -> Option<WireModel> {
+        if self.step < 2 {
+            return None;
+        }
+        if let Some((center, vr, sa)) = edge_poly_params(self.a, pt, self.sides) {
+            Some(poly_wire(center, vr, self.sides, sa))
+        } else {
+            Some(wire_seg(self.a, pt))
+        }
+    }
+}
+
+/// Compute polygon center, vertex-radius and start-angle from two edge endpoints.
+/// The polygon is placed on the left side of A→B (CCW convention).
+fn edge_poly_params(a: Vec3, b: Vec3, sides: u32) -> Option<(Vec3, f32, f32)> {
+    let edge_len = a.distance(b);
+    if edge_len < 1e-6 {
+        return None;
+    }
+    // vertex_radius = edge_len / (2 * sin(π/N))
+    let vr = edge_len / (2.0 * (PI / sides as f32).sin());
+    // inradius = vr * cos(π/N) = edge_len / (2 * tan(π/N))
+    let inradius = vr * (PI / sides as f32).cos();
+    // Center: on the left perpendicular bisector of A→B
+    let dir = (b - a) / edge_len;
+    let perp = Vec3::new(-dir.y, dir.x, 0.0); // CCW left
+    let mid = (a + b) * 0.5;
+    let center = mid + perp * inradius;
+    // First vertex = A
+    let sa = angle_xy(center, a);
+    Some((center, vr, sa))
+}

src/modules/home/draw/spline.rs

@@ -0,0 +1,120 @@
+// Spline tool — ribbon definition + interactive command.
+//
+// Command:  SPLINE (SPL)
+//   Click to add control points.  Enter (≥2 pts) → commits EntityType::Spline.
+
+use acadrust::types::Vector3;
+use acadrust::{EntityType, Spline};
+
+use crate::command::{CadCommand, CmdResult};
+use crate::modules::{IconKind, ModuleEvent, ToolDef};
+use crate::scene::wire_model::WireModel;
+use glam::Vec3;
+
+#[allow(dead_code)]
+pub fn tool() -> ToolDef {
+    ToolDef {
+        id: "SPLINE",
+        label: "Spline",
+        icon: IconKind::Svg(include_bytes!("../../../../assets/icons/spline.svg")),
+        event: ModuleEvent::Command("SPLINE".to_string()),
+    }
+}
+
+pub struct SplineCommand {
+    pts: Vec<Vec3>,
+}
+
+impl SplineCommand {
+    pub fn new() -> Self {
+        Self { pts: Vec::new() }
+    }
+
+    fn build(&self) -> Option<EntityType> {
+        if self.pts.len() < 2 {
+            return None;
+        }
+        let control_points = self
+            .pts
+            .iter()
+            .map(|p| Vector3::new(p.x as f64, p.y as f64, p.z as f64))
+            .collect();
+        let n = self.pts.len();
+        // Uniform open knot vector for degree-3 clamped B-spline
+        let degree = 3_i32.min((n - 1) as i32);
+        let knots = uniform_knots(n, degree as usize);
+        let spline = Spline {
+            degree,
+            control_points,
+            knots,
+            ..Default::default()
+        };
+        Some(EntityType::Spline(spline))
+    }
+}
+
+fn uniform_knots(n: usize, d: usize) -> Vec<f64> {
+    let m = n + d + 1;
+    (0..m)
+        .map(|i| {
+            if i <= d {
+                0.0
+            } else if i >= m - d - 1 {
+                1.0
+            } else {
+                (i - d) as f64 / (n - d) as f64
+            }
+        })
+        .collect()
+}
+
+impl CadCommand for SplineCommand {
+    fn name(&self) -> &'static str {
+        "SPLINE"
+    }
+
+    fn prompt(&self) -> String {
+        if self.pts.is_empty() {
+            "SPLINE  Specify first control point:".into()
+        } else {
+            format!(
+                "SPLINE  Specify next point  [{} pts | Enter=done]:",
+                self.pts.len()
+            )
+        }
+    }
+
+    fn on_point(&mut self, pt: Vec3) -> CmdResult {
+        self.pts.push(pt);
+        CmdResult::NeedPoint
+    }
+
+    fn on_enter(&mut self) -> CmdResult {
+        match self.build() {
+            Some(e) => CmdResult::CommitEntity(e),
+            None => CmdResult::Cancel,
+        }
+    }
+
+    fn on_escape(&mut self) -> CmdResult {
+        match self.build() {
+            Some(e) => CmdResult::CommitEntity(e),
+            None => CmdResult::Cancel,
+        }
+    }
+
+    fn on_mouse_move(&mut self, pt: Vec3) -> Option<WireModel> {
+        if self.pts.is_empty() {
+            return None;
+        }
+        // Show all committed points + cursor as a connected polyline.
+        let mut pts: Vec<[f32; 3]> = self.pts.iter().map(|p| [p.x, p.y, p.z]).collect();
+        pts.push([pt.x, pt.y, pt.z]);
+        Some(WireModel::solid(
+            "rubber_band".into(),
+            pts,
+            WireModel::CYAN,
+            false,
+        ))
+    }
+}