diff --git a/src/app/update/viewport.rs b/src/app/update/viewport.rs
index dc9d44dff..61acc136e 100644
--- a/src/app/update/viewport.rs
+++ b/src/app/update/viewport.rs
@@ -1034,12 +1034,73 @@ impl OpenCADStudio {
             // snapping must drop its foot from this point, including when a
             // hot-grip set is moved by the same drag vector.
             self.snapper.from_point = Some(grip.origin_world.as_vec3());
+            self.snapper.from_point = Some(grip.origin_world.as_vec3());
+
+            // Keep the updated drafting basis from main so grid/snap follows the
+            // current drafting axes, including isometric drafting and SNAPANG.
             let (go, gr) = self.drafting_grid_basis(i);
+
+            let base = grip.origin_world;
+            let ucs_xf = self.tabs[i].ucs_xform();
+
+            let mut construction_cursor = if self.ortho_mode {
+                Some(drafting_constrain(
+                    raw,
+                    base,
+                    &ucs_xf,
+                    self.isometric_drafting,
+                    self.iso_plane,
+                    self.snap_angle_deg,
+                ))
+            } else if self.polar_mode {
+                let pt = polar_constrain_near(
+                    raw,
+                    base,
+                    self.polar_increment_deg,
+                    view_rot,
+                    eye,
+                    bounds,
+                    self.snapper.osnap_radius_px,
+                    &ucs_xf,
+                );
+
+                // POLAR being enabled is not enough: the cursor must actually
+                // be engaged on one of the polar tracking rays.
+                let delta = pt - base;
+                let step = (self.polar_increment_deg as f64).to_radians();
+                let angle = delta.y.atan2(delta.x);
+
+                let polar_engaged = step > 1e-9
+                    && (((angle / step).round() * step - angle).abs() < 1e-3)
+                    && (delta.x * delta.x + delta.y * delta.y).sqrt() > 1e-9;
+
+                if polar_engaged {
+                    Some(pt)
+                } else {
+                    None
+                }
+            } else {
+                None
+            };
+
+            if let Some(pt) = construction_cursor.as_mut() {
+                if self.tabs[i].active_ucs.is_none() {
+                    pt.z = base.z;
+                }
+            }
             // `raw` is already model space (viewport camera or paper→model),
             // and the wires are model space, so the snap result is model.
-            let snap_hit =
-                self.snapper
-                    .snap(raw, p, &snap_candidates, view_rot, eye, bounds, go, gr);
+            let snap_hit = self.snapper.snap(
+                raw,
+                p,
+                &snap_candidates,
+                view_rot,
+                eye,
+                bounds,
+                go,
+                gr,
+                construction_cursor,
+            );
 
             self.tabs[i].snap_result = snap_hit;
 
@@ -1459,6 +1520,64 @@ impl OpenCADStudio {
                 // base only matters for typed-input precision, so hand it
                 // the downcast point here.
                 self.snapper.from_point = self.last_point.map(|p| p.as_vec3());
+
+                // Build the temporary construction direction before OSNAP.
+                // Intersection can then test the active rubber-band against
+                // existing geometry (#704).
+                let construction_cursor = if is_window_corner {
+                    None
+                } else {
+                    self.last_point.and_then(|base| {
+                        let ucs_xf = self.tabs[i].ucs_xform();
+
+                        let mut pt = if self.ortho_mode {
+                            Some(drafting_constrain(
+                                snap_cursor,
+                                base,
+                                &ucs_xf,
+                                self.isometric_drafting,
+                                self.iso_plane,
+                                self.snap_angle_deg,
+                            ))
+                        } else if self.polar_mode {
+                            let pt = polar_constrain_near(
+                                snap_cursor,
+                                base,
+                                self.polar_increment_deg,
+                                view_rot,
+                                eye,
+                                bounds,
+                                self.snapper.osnap_radius_px,
+                                &ucs_xf,
+                            );
+
+                            // POLAR being enabled is not enough: the cursor must actually
+                            // be engaged on one of the polar tracking rays.
+                            let delta = pt - base;
+                            let step = (self.polar_increment_deg as f64).to_radians();
+                            let angle = delta.y.atan2(delta.x);
+
+                            let polar_engaged = step > 1e-9
+                                && (((angle / step).round() * step - angle).abs() < 1e-3)
+                                && (delta.x * delta.x + delta.y * delta.y).sqrt() > 1e-9;
+
+                            if polar_engaged {
+                                Some(pt)
+                            } else {
+                                None
+                            }
+                        } else {
+                            None
+                        }?;
+
+                        if self.tabs[i].active_ucs.is_none() {
+                            pt.z = base.z;
+                        }
+
+                        Some(pt)
+                    })
+                };
+
                 self.snapper.snap(
                     snap_cursor,
                     p,
@@ -1468,6 +1587,7 @@ impl OpenCADStudio {
                     bounds,
                     go,
                     gr,
+                    construction_cursor,
                 )
             };
 
@@ -2123,7 +2243,7 @@ impl OpenCADStudio {
         let (go, gr) = self.drafting_grid_basis(i);
         let snap_hit = self
             .snapper
-            .snap(raw, p, &snap_candidates, view_rot, eye, bounds, go, gr);
+            .snap(raw, p, &snap_candidates, view_rot, eye, bounds, go, gr, None);
         let world = snap_hit.map(|s| s.world).unwrap_or(raw);
         self.tabs[i].snap_result = snap_hit;
         if let Some(s) = self.tabs[i].snap_result.as_mut() {
@@ -2785,6 +2905,61 @@ impl OpenCADStudio {
                 } else {
                     let (go, gr) = self.drafting_grid_basis(i);
                     self.snapper.from_point = self.last_point.map(|p| p.as_vec3());
+
+                    let construction_cursor = if is_window_corner {
+                        None
+                    } else {
+                        self.last_point.and_then(|base| {
+                            let ucs_xf = self.tabs[i].ucs_xform();
+
+                            let mut pt = if self.ortho_mode {
+                                Some(drafting_constrain(
+                                snap_cursor,
+                                base,
+                                &ucs_xf,
+                                self.isometric_drafting,
+                                self.iso_plane,
+                                self.snap_angle_deg,
+                            ))
+                           } else if self.polar_mode {
+                                let pt = polar_constrain_near(
+                                    snap_cursor,
+                                    base,
+                                    self.polar_increment_deg,
+                                    view_rot,
+                                    eye,
+                                    bounds,
+                                    self.snapper.osnap_radius_px,
+                                    &ucs_xf,
+                                );
+
+                                // POLAR being enabled is not enough: the cursor must actually
+                                // be engaged on one of the polar tracking rays.
+                                let delta = pt - base;
+                                let step = (self.polar_increment_deg as f64).to_radians();
+                                let angle = delta.y.atan2(delta.x);
+
+                                let polar_engaged = step > 1e-9
+                                    && (((angle / step).round() * step - angle).abs() < 1e-3)
+                                    && (delta.x * delta.x + delta.y * delta.y).sqrt() > 1e-9;
+
+                                if polar_engaged {
+                                    Some(pt)
+                                } else {
+                                    None
+                                }
+                            } else {
+                                None
+                            }?;
+
+                            if self.tabs[i].active_ucs.is_none() {
+                                pt.z = base.z;
+                            }
+
+                            Some(pt)
+                        })
+                    };
+
                     self.snapper.snap(
                         snap_cursor,
                         p,
@@ -2794,6 +2969,7 @@ impl OpenCADStudio {
                         bounds,
                         go,
                         gr,
+                        construction_cursor,
                     )
                 };
                 // Snap runs in model space; the result is already model.
diff --git a/src/snap.rs b/src/snap.rs
index 82d2e54e4..9450b56e6 100644
--- a/src/snap.rs
+++ b/src/snap.rs
@@ -848,6 +848,7 @@ impl Snapper {
             bounds,
             Vec3::ZERO,
             (Vec3::X, Vec3::Y, Vec3::Z),
+            None,
         )
     }
 
@@ -864,6 +865,7 @@ impl Snapper {
         // rotated or isometric grid the user sees.
         grid_origin: Vec3,
         grid_axes: (Vec3, Vec3, Vec3),
+        construction_cursor: Option<glam::DVec3>,
     ) -> Option<SnapResult> {
         // Object-snap selection is priority-then-distance, NOT nearest-wins.
         // "Continuous" snaps (Nearest, Perpendicular, …) sit on the geometry
@@ -1215,6 +1217,97 @@ impl Snapper {
             }
         }
 
+        // ── Intersection with active construction segment (#704) ──────────
+        //
+        // The existing Intersection pass below only compares document
+        // entities with each other. Also compare the rubber-band currently
+        // being drawn against existing geometry.
+        if self.is_on(SnapType::Intersection) {
+            if let (Some(from), Some(to)) = (self.from_point, construction_cursor) {
+                let from = from.as_dvec3();
+                if (to - from).length_squared() > 1e-18 {
+                    // Active/deferred Intersection uses the actual nearby wires directly.
+                    // The interaction candidate set may contain wires while its optional
+                    // segment index is empty.
+                    for wire in wires.iter() {
+                        if !wire_in_range(wire) {
+                            continue;
+                        }
+
+                        for index in 0..wire.points.len().saturating_sub(1) {
+                            let b0 = wp_f64(wire, index);
+                            let b1 = wp_f64(wire, index + 1);
+
+                            if let Some(pt) = ray_segment_intersect_3d(from, to, b0, b1) {
+                                if (pt - from).length_squared() > 1e-18 {
+                                    try_pt(pt, SnapType::Intersection);
+                                }
+                            }
+                        }
+                    }
+                }
+            }
+        }
+        // ── Intersection with active perpendicular OTRACK ray (#704) ──────
+        //
+        // A perpendicular tracking ray is not part of the command's ordinary
+        // ORTHO/POLAR construction cursor. When the cursor is actually tracking
+        // one of those rays, allow Intersection to stop it on nearby geometry.
+        if self.is_on(SnapType::Intersection)
+            && self.otrack_enabled
+            && self.is_on(SnapType::Perpendicular)
+        {
+            for (gi, &origin) in self.tracking_points.iter().enumerate() {
+                let Some(perp_dirs) = self.tracking_perp_dirs.get(gi) else {
+                    continue;
+                };
+
+                for &dir in perp_dirs {
+                    // Project the cursor onto this perpendicular tracking line.
+                    let rel = cursor_world - origin;
+                    let t = rel.x * dir.x + rel.y * dir.y;
+
+                    let aligned = glam::DVec3::new(
+                        origin.x + dir.x * t,
+                        origin.y + dir.y * t,
+                        origin.z,
+                    );
+
+                    // Only consider the ray when the cursor is genuinely tracking it.
+                    // This prevents Intersection from behaving like Nearest.
+                    let aligned_screen = world_to_screen(aligned, view_rot, eye, bounds);
+                    if dist2(aligned_screen, cursor_screen) > radius2 {
+                        continue;
+                    }
+
+                    // Perpendicular tracking is an infinite line, but once the cursor
+                    // chooses a side we only want intersections forward on that side.
+                    let dir_to_cursor = if t >= 0.0 { dir } else { -dir };
+                    let through = origin + dir_to_cursor;
+
+                    for wire in wires.iter() {
+                        if !wire_in_range(wire) {
+                            continue;
+                        }
+
+                        for index in 0..wire.points.len().saturating_sub(1) {
+                            let b0 = wp_f64(wire, index);
+                            let b1 = wp_f64(wire, index + 1);
+
+                            if let Some(pt) =
+                                ray_segment_intersect_3d(origin, through, b0, b1)
+                            {
+                                // Do not re-offer the tracking origin itself.
+                                if (pt - origin).length_squared() > 1e-18 {
+                                    try_pt(pt, SnapType::Intersection);
+                                }
+                            }
+                        }
+                    }
+                }
+            }
+        }
+
         // ── Intersection — segment-segment intersections (pairwise, gated) ──
         if self.is_on(SnapType::Intersection)
             && (local_segments.is_some() || allow_unindexed_pairwise)
@@ -2010,6 +2103,56 @@ fn perp_foot(query: glam::DVec3, p0: glam::DVec3, p1: glam::DVec3) -> Option<gla
     ))
 }
 
+/// Intersection between a forward construction ray and an existing segment.
+///
+/// The ray starts at `ray_origin` and points toward `ray_through`, but extends
+/// indefinitely forward. The existing geometry remains a finite segment.
+///
+/// Like `seg_intersect_3d`, this is a true 3D intersection: the XY projections
+/// must cross and both geometries must have the same Z at the crossing.
+fn ray_segment_intersect_3d(
+    ray_origin: glam::DVec3,
+    ray_through: glam::DVec3,
+    b0: glam::DVec3,
+    b1: glam::DVec3,
+) -> Option<glam::DVec3> {
+    let d1x = ray_through.x - ray_origin.x;
+    let d1y = ray_through.y - ray_origin.y;
+    let d2x = b1.x - b0.x;
+    let d2y = b1.y - b0.y;
+
+    let cross = d1x * d2y - d1y * d2x;
+    if cross.abs() < 1e-9 {
+        return None;
+    }
+
+    let ex = b0.x - ray_origin.x;
+    let ey = b0.y - ray_origin.y;
+
+    let t = (ex * d2y - ey * d2x) / cross;
+    let s = (ex * d1y - ey * d1x) / cross;
+
+    // `t >= 0`: only forward along the construction ray.
+    // `s` must remain inside the existing finite segment.
+    if t < 0.0 || s < 0.0 || s > 1.0 {
+        return None;
+    }
+
+    let za = ray_origin.z + t * (ray_through.z - ray_origin.z);
+    let zb = b0.z + s * (b1.z - b0.z);
+    let tol = 1e-6_f64.max(1e-9 * za.abs().max(zb.abs()));
+
+    if (za - zb).abs() > tol {
+        return None;
+    }
+
+    Some(glam::DVec3::new(
+        ray_origin.x + t * d1x,
+        ray_origin.y + t * d1y,
+        0.5 * (za + zb),
+    ))
+}
+
 /// XY-plane segment-segment intersection.  Returns `None` if parallel or outside.
 /// True 3D intersection of two segments: the point where their plan (XY)
 /// projections cross **and** both segments are at the same height there. Returns