diff --git a/Cargo.lock b/Cargo.lock
index 6c0ac18c5..10090ba49 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -896,7 +896,7 @@ checksum = "fc652a48c352aef3ea3aed32080501cf3ef6ed5da78602a020c991775b0aff04"
 [[package]]
 name = "cadkernel"
 version = "0.1.0"
-source = "git+https://github.com/HakanSeven12/cadkernel.git?rev=935d90b86a99377dc95cba92e99a9b109180e2f6#935d90b86a99377dc95cba92e99a9b109180e2f6"
+source = "git+https://github.com/HakanSeven12/cadkernel.git?rev=d3830bb5230bd80e9f8abaa78b9f85d15161536a#d3830bb5230bd80e9f8abaa78b9f85d15161536a"
 dependencies = [
  "acadrust",
  "cavalier_contours",
@@ -907,7 +907,7 @@ dependencies = [
 [[package]]
 name = "cadkernel-constraints"
 version = "0.1.0"
-source = "git+https://github.com/HakanSeven12/cadkernel.git?rev=935d90b86a99377dc95cba92e99a9b109180e2f6#935d90b86a99377dc95cba92e99a9b109180e2f6"
+source = "git+https://github.com/HakanSeven12/cadkernel.git?rev=d3830bb5230bd80e9f8abaa78b9f85d15161536a#d3830bb5230bd80e9f8abaa78b9f85d15161536a"
 dependencies = [
  "nalgebra",
 ]
diff --git a/Cargo.toml b/Cargo.toml
index 6d559022b..ab49a55da 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -32,8 +32,8 @@ rfd = "0.17"
 clap = { version = "4", features = ["derive", "string"] }
 env_logger = "0.11"
 acadrust = { git = "https://github.com/HakanSeven12/cadcodec.git", rev = "6f3711809e39e9ffdf16a63086079b6475d97175", features = ["serde"] }
-cadkernel = { git = "https://github.com/HakanSeven12/cadkernel.git", rev = "935d90b86a99377dc95cba92e99a9b109180e2f6", features = ["acis", "offset"] }
-cadkernel-constraints = { git = "https://github.com/HakanSeven12/cadkernel.git", rev = "935d90b86a99377dc95cba92e99a9b109180e2f6" }
+cadkernel = { git = "https://github.com/HakanSeven12/cadkernel.git", rev = "d3830bb5230bd80e9f8abaa78b9f85d15161536a", features = ["acis", "offset"] }
+cadkernel-constraints = { git = "https://github.com/HakanSeven12/cadkernel.git", rev = "d3830bb5230bd80e9f8abaa78b9f85d15161536a" }
 dwg-thumbnailer = { path = "crates/dwg-thumbnailer" }
 flate2 = "1"
 image = { version = "0.25", default-features = false, features = ["png", "jpeg", "bmp", "tiff"] }
diff --git a/src/entities/dimension.rs b/src/entities/dimension.rs
index 667990bd2..c2f704fa2 100644
--- a/src/entities/dimension.rs
+++ b/src/entities/dimension.rs
@@ -3768,9 +3768,9 @@ fn tessellate_dimension_inner(
     // DIMTMOVE=1 connects the dimension line to rendered text.
     if let Some(s) = style {
         if s.dimtmove == 1 {
-            if let Some((anchor, txt)) = dimtmove_leader_endpoints(dim, text_layout.position) {
+            if let Some((anchor, txt, under_text)) = dimtmove_leader_endpoints(dim, text_layout) {
                 let gap = dim_txt as f32 * 0.5;
-                if (txt - anchor).length() > gap * 2.0 {
+                if under_text || (txt - anchor).length() > gap * 2.0 {
                     add_segment_with_text_break(
                         &mut geom.dim_lines,
                         anchor,
@@ -4297,28 +4297,51 @@ fn split_ext_lines(points: &[[f32; 3]]) -> (Vec<[f32; 3]>, Vec<[f32; 3]>) {
 }
 
 /// Endpoints for the DIMTMOVE=1 leader.
-fn dimtmove_leader_endpoints(dim: &Dimension, txt: Vec3) -> Option<(Vec3, Vec3)> {
+fn dimtmove_leader_endpoints(
+    dim: &Dimension,
+    text: DimensionTextLayout,
+) -> Option<(Vec3, Vec3, bool)> {
     let lv = |v| vec3_local(v);
-    let anchor = match dim {
+    let txt = text.position;
+    let linear = |first: Vec3, second: Vec3, definition: Vec3, axis: [f64; 2]| {
+        let bounds = text.break_box?;
+        let xy = |point: Vec3| [point.x as f64, point.y as f64];
+        let (leader, under_text) = cadkernel::geom2d::linear_dimension_leader(
+            cadkernel::geom2d::Line { start: xy(first), end: xy(second) },
+            xy(definition),
+            axis,
+            xy(txt),
+            [
+                (bounds.half_width + bounds.padding) as f64,
+                (bounds.half_height + bounds.padding) as f64,
+            ],
+            bounds.rotation,
+        )?;
+        let point = |p: [f64; 2]| Vec3::new(p[0] as f32, p[1] as f32, first.z);
+        Some((point(leader.start), point(leader.end), under_text))
+    };
+    match dim {
         Dimension::Linear(d) => {
-            let perp = Vec3::new(-(d.rotation.sin() as f32), d.rotation.cos() as f32, 0.0);
-            let first = lv(d.first_point);
-            let second = lv(d.second_point);
-            let def = lv(d.definition_point);
-            let off1 = def.dot(perp) - first.dot(perp);
-            let off2 = def.dot(perp) - second.dot(perp);
-            (first + perp * off1 + second + perp * off2) * 0.5
+            return linear(
+                lv(d.first_point),
+                lv(d.second_point),
+                lv(d.definition_point),
+                [d.rotation.cos(), d.rotation.sin()],
+            );
         }
         Dimension::Aligned(d) => {
             let first = lv(d.first_point);
             let second = lv(d.second_point);
-            let axis = normalized_or(second - first, Vec3::X);
-            let perp = Vec3::new(-axis.y, axis.x, 0.0);
-            let def = lv(d.definition_point);
-            let off1 = def.dot(perp) - first.dot(perp);
-            let off2 = def.dot(perp) - second.dot(perp);
-            (first + perp * off1 + second + perp * off2) * 0.5
+            return linear(
+                first,
+                second,
+                lv(d.definition_point),
+                [d.second_point.x - d.first_point.x, d.second_point.y - d.first_point.y],
+            );
         }
+        _ => {}
+    }
+    let anchor = match dim {
         Dimension::Radius(_) => return None,
         Dimension::Diameter(d) => {
             let chord = lv(d.angle_vertex);
@@ -4353,7 +4376,7 @@ fn dimtmove_leader_endpoints(dim: &Dimension, txt: Vec3) -> Option<(Vec3, Vec3)>
         }
         _ => return None,
     };
-    Some((anchor, txt))
+    Some((anchor, txt, false))
 }
 
 /// Build a rectangle of filled triangles sitting under the dim text, used
@@ -7188,8 +7211,10 @@ pub(crate) fn baked_large_radial_geometry(
         }
     }
     if style.is_some_and(|style| style.dimtmove == 1) {
-        if let Some((anchor, endpoint)) = dimtmove_leader_endpoints(dimension, text.position) {
-            if anchor.distance(endpoint) > text_height as f32 {
+        if let Some((anchor, endpoint, under_text)) =
+            dimtmove_leader_endpoints(dimension, text)
+        {
+            if under_text || anchor.distance(endpoint) > text_height as f32 {
                 add_segment_with_text_break(
                     &mut geometry.dim_lines,
                     anchor,
@@ -7527,3 +7552,89 @@ mod arch_format_tests {
         assert_eq!(format_engineering(-0.001, 2), "0'-0.00\"");
     }
 }
+
+#[cfg(test)]
+mod dimtmove_leader_tests {
+    use super::*;
+    use acadrust::entities::DimensionLinear;
+    use acadrust::types::Vector3;
+
+    fn v(x: f64, y: f64) -> Vector3 {
+        Vector3::new(x, y, 0.0)
+    }
+
+    fn layout(position: Vec3, half_width: f32) -> DimensionTextLayout {
+        DimensionTextLayout {
+            position,
+            width: half_width * 2.0,
+            break_box: Some(TextBreak {
+                center: position,
+                half_width,
+                half_height: 1.0,
+                padding: 0.0,
+                rotation: 0.0,
+            }),
+            horizontal: true,
+        }
+    }
+
+    /// Text outside along the axis → the dim line extends underneath the text.
+    #[test]
+    fn text_outside_extends_dim_line_under_text() {
+        let mut d = DimensionLinear::horizontal(v(0.0, 0.0), v(20.0, 0.0));
+        d.definition_point = v(0.0, -5.0); // dimension line at y=-5
+        let dim = Dimension::Linear(d);
+        // text anchor outside on the right: centre x=30, half width 3 → far edge 33
+        let txt = vec3_local(v(30.0, -3.0));
+        let (anchor, end, under) = dimtmove_leader_endpoints(&dim, layout(txt, 3.0)).expect("leader");
+        assert!(under, "outside text extends the dimension line");
+        assert!((anchor.x - 20.0).abs() < 1e-4 && (anchor.y + 5.0).abs() < 1e-4, "near end should be the dim line's right end (20,-5), got {anchor:?}");
+        assert!((end.x - 33.0).abs() < 1e-4 && (end.y + 5.0).abs() < 1e-4, "far end should be the text's far edge (33,-5), got {end:?}");
+    }
+
+    /// Text outside on the left → extends leftwards.
+    #[test]
+    fn text_outside_left_extends_leftwards() {
+        let mut d = DimensionLinear::horizontal(v(0.0, 0.0), v(20.0, 0.0));
+        d.definition_point = v(0.0, -5.0);
+        let dim = Dimension::Linear(d);
+        let txt = vec3_local(v(-12.0, -3.0));
+        let (anchor, end, under) = dimtmove_leader_endpoints(&dim, layout(txt, 2.0)).expect("leader");
+        assert!(under);
+        assert!((anchor.x - 0.0).abs() < 1e-4, "near end should be the dim line's left end, got {anchor:?}");
+        assert!((end.x + 14.0).abs() < 1e-4, "far end should be the text's far edge at -14, got {end:?}");
+    }
+
+    /// Text still inside (only moved up/down) → leader from the dim line to the text.
+    #[test]
+    fn text_inside_connects_to_text() {
+        let mut d = DimensionLinear::horizontal(v(0.0, 0.0), v(20.0, 0.0));
+        d.definition_point = v(0.0, -5.0);
+        let dim = Dimension::Linear(d);
+        let txt = vec3_local(v(10.0, 2.0));
+        let (anchor, end, under) = dimtmove_leader_endpoints(&dim, layout(txt, 3.0)).expect("leader");
+        assert!(!under, "inside → keep the connect-to-text leader (text break allowed)");
+        assert!((anchor.x - 10.0).abs() < 1e-4 && (anchor.y + 5.0).abs() < 1e-4, "anchor should be the dim line point facing the text, got {anchor:?}");
+        assert!((end.y - 2.0).abs() < 1e-4, "end should be the text position, got {end:?}");
+    }
+
+    /// Radius dimensions draw no leader (unchanged).
+    #[test]
+    fn radius_has_no_leader() {
+        let r = acadrust::entities::DimensionRadius::new(v(0.0, 0.0), v(0.0, 5.0));
+        assert!(dimtmove_leader_endpoints(&Dimension::Radius(r), layout(vec3_local(v(0.0, 8.0)), 2.0)).is_none());
+    }
+
+    #[test]
+    fn extension_does_not_draw_through_text() {
+        let mut d = DimensionLinear::horizontal(v(0.0, 0.0), v(20.0, 0.0));
+        d.definition_point = v(0.0, -5.0);
+        let text = layout(Vec3::new(30.0, -5.0, 0.0), 3.0);
+        let (start, end, outside) = dimtmove_leader_endpoints(&Dimension::Linear(d), text).unwrap();
+        assert!(outside);
+        let mut points = Vec::new();
+        add_segment_with_text_break(&mut points, start, end, text.break_box);
+        let finite: Vec<_> = points.into_iter().filter(|point| point[0].is_finite()).collect();
+        assert_eq!(finite, vec![[20.0, -5.0, 0.0], [27.0, -5.0, 0.0]]);
+    }
+}
diff --git a/tests/dim_leader_render_check.rs b/tests/dim_leader_render_check.rs
new file mode 100644
index 000000000..8f0e9916c
--- /dev/null
+++ b/tests/dim_leader_render_check.rs
@@ -0,0 +1,78 @@
+//! Check DIMTMOVE through the scene's actual dimension tessellation.
+
+use acadrust::entities::{Dimension, DimensionAligned, DimensionLinear};
+use acadrust::types::Vector3;
+use acadrust::xdata::XDataValue;
+use acadrust::EntityType;
+use OpenCADStudio::entities::dim_override as ov;
+use OpenCADStudio::scene::Scene;
+
+#[test]
+fn dim_leader_extends_only_when_requested() {
+    for aligned in [false, true] {
+        for movement in [0, 1, 2] {
+            for (text_x, text_y) in [
+                (-18.0, 89.0),
+                (98.0, 89.0),
+                (19.9, 89.0),
+                (80.1, 89.0),
+                (-18.0, 86.0),
+                (98.0, 86.0),
+            ] {
+                let mut scene = Scene::new();
+                let first = Vector3::new(20.0, 100.0, 0.0);
+                let second = Vector3::new(80.0, 100.0, 0.0);
+                let definition = Vector3::new(20.0, 86.0, 0.0);
+                let mut dim = if aligned {
+                    let mut d = DimensionAligned::new(first, second);
+                    d.definition_point = definition;
+                    Dimension::Aligned(d)
+                } else {
+                    let mut d = DimensionLinear::horizontal(first, second);
+                    d.definition_point = definition;
+                    Dimension::Linear(d)
+                };
+                let base = dim.base_mut();
+                base.definition_point = definition;
+                base.text_middle_point = Vector3::new(text_x, text_y, 0.0);
+                base.insertion_point = base.text_middle_point;
+                base.text_user_positioned = true;
+                base.style_name = "Standard".into();
+                let handle = scene.add_entity(EntityType::Dimension(dim));
+                for (code, value) in [
+                    (ov::DIMTMOVE, XDataValue::Integer16(movement)),
+                    (ov::DIMTXT, XDataValue::Real(3.5)),
+                    (ov::DIMASZ, XDataValue::Real(3.5)),
+                    (ov::DIMGAP, XDataValue::Real(1.0)),
+                ] {
+                    ov::set(&mut scene.document, handle, code, Some(value));
+                }
+                scene.bump_entities(&[(handle, OpenCADStudio::scene::ChangeKind::Modified)]);
+                let wires = scene.entity_wires();
+                let extension = wires.iter().any(|wire| {
+                    (0..wire.points.len().saturating_sub(1)).any(|index| {
+                        let a = wire.point_world(index, 1.0);
+                        let b = wire.point_world(index + 1, 1.0);
+                        if !a.is_finite() || !b.is_finite() {
+                            return false;
+                        }
+                        let near = if text_x > 80.0 { 80.0 } else { 20.0 };
+                        (a.x - near).abs() < 1e-4
+                            && (a.y - 86.0).abs() < 1e-4
+                            && (b.y - 86.0).abs() < 1e-4
+                            && if text_x > 80.0 {
+                                b.x > text_x
+                            } else {
+                                b.x < text_x
+                            }
+                    })
+                });
+                assert_eq!(
+                    extension,
+                    movement == 1 && text_y == 89.0,
+                    "aligned={aligned}, DIMTMOVE={movement}, text=({text_x},{text_y})"
+                );
+            }
+        }
+    }
+}