feat(lwpolyline): render the wide-polyline band via the wire shader

A wide polyline's flat band was drawn by the hatch pipeline: a solid fill
with only draw-order depth. It ignored the entity linetype (the width
"crushed" the dash pattern) and showed through 3-D geometry in a tilted view.

Draw the band from the polyline's own centre-line wire instead. A new
`WireModel.world_width` (drawing units) makes the wire vertex shader expand
the quad by `world_half_width / world_per_pixel` (clamped to a hairline), so
the band is sized in world units and tracks zoom. Because it is now a wire:

- the GPU dash shader dashes the band by arc-length — the linetype applies;
- it is depth-tested at the polyline elevation — no draw-order see-through;
- no CPU band triangles or per-dash geometry are generated.

`world_half_width` rides in `WireConst` (native, replacing a pad) and the web
`WireInstance` (loc 14); both wire shaders branch on it. The tessellator sets
`world_width` from the LwPolyline width on the Contour / SegmentedLines arms,
and the model-space fill loop no longer emits a hatch band for any LwPolyline.
Pick still uses the band polygon (`pick_tris`).

Blocks keep the hatch band: `LocalWire` carries no `world_width` (finalize
zeroes it), so a scaled insert still scales its band correctly.

Co-Authored-By: Claude Opus 4.8 <[email protected]>

src/app/update/viewport.rs

@@ -1235,6 +1235,7 @@ pub(super) fn on_tick(&mut self, t: Instant) -> Task<Message> {
                                 let far_pos = base + dir * far;
                                 let far_neg = base - dir * far;
                                 let guide = crate::scene::WireModel {
+                                    world_width: 0.0,
                                     fill_is_3d: false,
                                     pick_tris: Vec::new(),
                                     pick_tris_low: Vec::new(),
@@ -1273,6 +1274,7 @@ pub(super) fn on_tick(&mut self, t: Instant) -> Task<Message> {
                             let far_pos = h.base + h.dir * far;
                             let far_neg = h.base - h.dir * far;
                             previews.push(crate::scene::WireModel {
+                                world_width: 0.0,
                                 fill_is_3d: false,
                                 pick_tris: Vec::new(),
                                 pick_tris_low: Vec::new(),

src/entities/dimension.rs

@@ -1352,6 +1352,7 @@ fn tessellate_dimension_inner(
             let (ext1, ext2) = split_ext_lines(&geom.ext_lines);
             if !ext1.is_empty() {
                 wires.push(WireModel {
+                    world_width: 0.0,
                     fill_is_3d: false,
                     pick_tris: Vec::new(),
                     pick_tris_low: Vec::new(),
@@ -1378,6 +1379,7 @@ fn tessellate_dimension_inner(
             }
             if !ext2.is_empty() {
                 wires.push(WireModel {
+                    world_width: 0.0,
                     fill_is_3d: false,
                     pick_tris: Vec::new(),
                     pick_tris_low: Vec::new(),
@@ -1404,6 +1406,7 @@ fn tessellate_dimension_inner(
             }
         } else {
             wires.push(WireModel {
+                world_width: 0.0,
                 fill_is_3d: false,
                 pick_tris: Vec::new(),
                 pick_tris_low: Vec::new(),
@@ -1431,6 +1434,7 @@ fn tessellate_dimension_inner(
     }
 
     wires.push(WireModel {
+        world_width: 0.0,
         fill_is_3d: false,
         pick_tris: Vec::new(),
         pick_tris_low: Vec::new(),
@@ -1474,6 +1478,7 @@ fn tessellate_dimension_inner(
                     aci_to_rgba(&c)
                 };
                 wires.push(WireModel {
+                    world_width: 0.0,
                     fill_is_3d: false,
                     pick_tris: Vec::new(),
                     pick_tris_low: Vec::new(),

src/entities/leader.rs

@@ -590,6 +590,7 @@ impl LeaderTess for Leader {
 
         if verts.len() < 2 {
             return WireModel {
+                world_width: 0.0,
                 fill_is_3d: false,
                 pick_tris: Vec::new(),
                 pick_tris_low: Vec::new(),
@@ -696,6 +697,7 @@ impl LeaderTess for Leader {
         }
 
         WireModel {
+            world_width: 0.0,
             fill_is_3d: false,
             pick_tris: Vec::new(),
             pick_tris_low: Vec::new(),

src/entities/multileader.rs

@@ -1404,6 +1404,7 @@ impl MultiLeaderTess for MultiLeader {
         // WireModels so the renderer respects per-piece coloring.
         let mut wires: Vec<WireModel> = Vec::new();
         wires.push(WireModel {
+            world_width: 0.0,
             fill_is_3d: false,
             pick_tris: Vec::new(),
             pick_tris_low: Vec::new(),
@@ -1693,6 +1694,7 @@ impl MultiLeaderTess for MultiLeader {
                         xy = xy.max(y);
                     }
                     wires.push(WireModel {
+                        world_width: 0.0,
                         fill_is_3d: false,
                         pick_tris: Vec::new(),
                         pick_tris_low: Vec::new(),
@@ -1760,6 +1762,7 @@ impl MultiLeaderTess for MultiLeader {
                         wcs_corners[3],
                     ];
                     wires.push(WireModel {
+                        world_width: 0.0,
                         fill_is_3d: false,
                         pick_tris: Vec::new(),
                         pick_tris_low: Vec::new(),
@@ -1795,6 +1798,7 @@ impl MultiLeaderTess for MultiLeader {
                         wcs_corners[0],
                     ];
                     wires.push(WireModel {
+                        world_width: 0.0,
                         fill_is_3d: false,
                         pick_tris: Vec::new(),
                         pick_tris_low: Vec::new(),

src/entities/table.rs

@@ -753,6 +753,7 @@ pub fn tessellate_table(
     let mk =
         |color: [f32; 4], points: Vec<[f32; 3]>, fill_tris: Vec<[f32; 3]>, lw: f32| -> WireModel {
             WireModel {
+                world_width: 0.0,
                 fill_is_3d: false,
                 pick_tris: Vec::new(),
                 pick_tris_low: Vec::new(),

src/modules/annotate/aligned_dim.rs

@@ -186,6 +186,7 @@ impl CadCommand for AlignedDimensionCommand {
         let p1 = p1.as_vec3();
         let p2 = p2.as_vec3();
         Some(WireModel {
+            world_width: 0.0,
             fill_is_3d: false,
             pick_tris: Vec::new(),
             pick_tris_low: Vec::new(),
@@ -237,6 +238,7 @@ fn preview_aligned(p1: DVec3, p2: DVec3, dim_pt: DVec3) -> WireModel {
     let d1 = d1.as_vec3();
     let d2 = d2.as_vec3();
     WireModel {
+        world_width: 0.0,
         fill_is_3d: false,
         pick_tris: Vec::new(),
         pick_tris_low: Vec::new(),

src/modules/annotate/angular_dim.rs

@@ -130,6 +130,7 @@ fn v3(pt: DVec3) -> Vector3 {
 
 fn preview_wire(points: Vec<Vec3>) -> WireModel {
     WireModel {
+        world_width: 0.0,
         fill_is_3d: false,
         pick_tris: Vec::new(),
         pick_tris_low: Vec::new(),

src/modules/annotate/diameter_dim.rs

@@ -180,6 +180,7 @@ fn v3(p: DVec3) -> Vector3 {
 
 fn preview_line(a: Vec3, b: Vec3) -> WireModel {
     WireModel {
+        world_width: 0.0,
         fill_is_3d: false,
         pick_tris: Vec::new(),
         pick_tris_low: Vec::new(),

src/modules/annotate/dim_baseline.rs

@@ -179,6 +179,7 @@ impl CadCommand for DimBaselineCommand {
         let dim_line_pt2 = dim_line_pt2.as_vec3();
         let pt = pt.as_vec3();
         Some(WireModel {
+            world_width: 0.0,
             fill_is_3d: false,
             pick_tris: Vec::new(),
             pick_tris_low: Vec::new(),

src/modules/annotate/dim_continue.rs

@@ -159,6 +159,7 @@ impl CadCommand for DimContinueCommand {
         let dim_line_pt = p1 + perp * (dim_line_perp - p1.dot(perp));
         let dim_line_pt2 = pt + perp * (dim_line_perp - pt.dot(perp));
         Some(WireModel {
+            world_width: 0.0,
             fill_is_3d: false,
             pick_tris: Vec::new(),
             pick_tris_low: Vec::new(),

src/modules/annotate/dimjogline.rs

@@ -85,6 +85,7 @@ impl CadCommand for DimJogLineCommand {
         }
         let d = 0.3_f32;
         Some(WireModel {
+            world_width: 0.0,
             fill_is_3d: false,
             pick_tris: Vec::new(),
             pick_tris_low: Vec::new(),

src/modules/annotate/dimtedit.rs

@@ -100,6 +100,7 @@ impl CadCommand for DimTeditCommand {
         }
         let d = 0.2_f32;
         Some(WireModel {
+            world_width: 0.0,
             fill_is_3d: false,
             pick_tris: Vec::new(),
             pick_tris_low: Vec::new(),

src/modules/annotate/leader_cmd.rs

@@ -163,6 +163,7 @@ fn preview_wire(pts: &[Vec3]) -> WireModel {
         points.push([w2.x, w2.y, w2.z]);
     }
     WireModel {
+        world_width: 0.0,
         fill_is_3d: false,
         pick_tris: Vec::new(),
         pick_tris_low: Vec::new(),

src/modules/annotate/linear_dim.rs

@@ -218,6 +218,7 @@ fn v3(pt: DVec3) -> Vector3 {
 
 fn preview_wire(points: Vec<DVec3>) -> WireModel {
     WireModel {
+        world_width: 0.0,
         fill_is_3d: false,
         pick_tris: Vec::new(),
         pick_tris_low: Vec::new(),

src/modules/annotate/mleader_cmd.rs

@@ -150,6 +150,7 @@ fn preview_wire(pts: &[Vec3]) -> WireModel {
         points.push([w2.x, w2.y, w2.z]);
     }
     WireModel {
+        world_width: 0.0,
         fill_is_3d: false,
         pick_tris: Vec::new(),
         pick_tris_low: Vec::new(),

src/modules/annotate/mleader_edit.rs

@@ -458,6 +458,7 @@ impl CadCommand for MLeaderCollectCommand {
 
 fn preview_wire(pts: &[Vec3]) -> WireModel {
     WireModel {
+        world_width: 0.0,
         fill_is_3d: false,
         pick_tris: Vec::new(),
         pick_tris_low: Vec::new(),

src/modules/annotate/ordinate_dim.rs

@@ -121,6 +121,7 @@ fn ordinate_elbow(feature: DVec3, leader: DVec3, is_x: bool) -> DVec3 {
 
 fn preview_wire(points: Vec<Vec3>) -> WireModel {
     WireModel {
+        world_width: 0.0,
         fill_is_3d: false,
         pick_tris: Vec::new(),
         pick_tris_low: Vec::new(),

src/modules/annotate/qdim.rs

@@ -90,6 +90,7 @@ impl CadCommand for QdimCommand {
         }
         let d = 0.5_f32;
         Some(WireModel {
+            world_width: 0.0,
             fill_is_3d: false,
             pick_tris: Vec::new(),
             pick_tris_low: Vec::new(),

src/modules/annotate/radius_dim.rs

@@ -185,6 +185,7 @@ fn v3(pt: DVec3) -> Vector3 {
 
 fn preview_wire(points: Vec<Vec3>) -> WireModel {
     WireModel {
+        world_width: 0.0,
         fill_is_3d: false,
         pick_tris: Vec::new(),
         pick_tris_low: Vec::new(),

src/modules/annotate/table_cmd.rs

@@ -139,6 +139,7 @@ impl CadCommand for TableCommand {
             let y = pt.y;
             let z = pt.z;
             Some(WireModel {
+                world_width: 0.0,
                 fill_is_3d: false,
                 pick_tris: Vec::new(),
                 pick_tris_low: Vec::new(),

src/modules/annotate/tolerance_cmd.rs

@@ -84,6 +84,7 @@ impl CadCommand for ToleranceCommand {
         }
         let d = 0.15_f32;
         Some(WireModel {
+            world_width: 0.0,
             fill_is_3d: false,
             pick_tris: Vec::new(),
             pick_tris_low: Vec::new(),

src/modules/draw/draw/attdef.rs

@@ -160,6 +160,7 @@ impl CadCommand for AttdefCommand {
         // Show a small cross at the insertion point.
         let d = 0.15_f32;
         Some(WireModel {
+            world_width: 0.0,
             fill_is_3d: false,
             pick_tris: Vec::new(),
             pick_tris_low: Vec::new(),

src/modules/draw/draw/mline.rs

@@ -136,6 +136,7 @@ impl CadCommand for MlineCommand {
             .collect();
         pts.push([pt.x, pt.y, pt.z]);
         Some(WireModel {
+            world_width: 0.0,
             fill_is_3d: false,
             pick_tris: Vec::new(),
             pick_tris_low: Vec::new(),

src/modules/draw/draw/raster_image.rs

@@ -108,6 +108,7 @@ impl CadCommand for ImageCommand {
         let p3 = [origin.x, origin.y + world_height, origin.z];
 
         Some(WireModel {
+            world_width: 0.0,
             fill_is_3d: false,
             pick_tris: Vec::new(),
             pick_tris_low: Vec::new(),

src/modules/draw/draw/ray.rs

@@ -84,6 +84,7 @@ impl CadCommand for RayCommand {
         let dir = (pt - base).normalize_or_zero();
         let far = base + dir * DISPLAY_EXTENT;
         Some(WireModel {
+            world_width: 0.0,
             fill_is_3d: false,
             pick_tris: Vec::new(),
             pick_tris_low: Vec::new(),
@@ -179,6 +180,7 @@ impl CadCommand for XLineCommand {
         let far_pos = base + dir * DISPLAY_EXTENT;
         let far_neg = base - dir * DISPLAY_EXTENT;
         Some(WireModel {
+            world_width: 0.0,
             fill_is_3d: false,
             pick_tris: Vec::new(),
             pick_tris_low: Vec::new(),

src/modules/draw/draw/revcloud.rs

@@ -89,6 +89,7 @@ impl CadCommand for RevCloudCommand {
             self.points[0].z as f32,
         ]);
         Some(WireModel {
+            world_width: 0.0,
             fill_is_3d: false,
             pick_tris: Vec::new(),
             pick_tris_low: Vec::new(),

src/modules/draw/draw/wipeout.rs

@@ -114,6 +114,7 @@ impl CadCommand for WipeoutCommand {
                 let min = p1.min(pt);
                 let max = p1.max(pt);
                 Some(WireModel {
+                    world_width: 0.0,
                     fill_is_3d: false,
                     pick_tris: Vec::new(),
                     pick_tris_low: Vec::new(),
@@ -160,6 +161,7 @@ impl CadCommand for WipeoutCommand {
                     self.poly_pts[0].z as f32,
                 ]);
                 Some(WireModel {
+                    world_width: 0.0,
                     fill_is_3d: false,
                     pick_tris: Vec::new(),
                     pick_tris_low: Vec::new(),

src/modules/draw/inquiry/area.rs

@@ -69,6 +69,7 @@ impl CadCommand for AreaCommand {
         pts.push(f(pt));
         pts.push(f(self.points[0]));
         Some(WireModel {
+            world_width: 0.0,
             fill_is_3d: false,
             pick_tris: Vec::new(),
             pick_tris_low: Vec::new(),

src/modules/draw/inquiry/dist.rs

@@ -63,6 +63,7 @@ impl CadCommand for DistCommand {
         let p1 = self.first?;
         // The preview wire is purely visual, so f32 vertices are fine here.
         Some(WireModel {
+            world_width: 0.0,
             fill_is_3d: false,
             pick_tris: Vec::new(),
             pick_tris_low: Vec::new(),

src/modules/draw/inquiry/measuregeom.rs

@@ -67,6 +67,7 @@ impl MeasureGeomCommand {
     /// Build a cyan preview wire connecting the picked points and the cursor.
     fn preview_wire(name: &str, pts: Vec<[f32; 3]>) -> WireModel {
         WireModel {
+            world_width: 0.0,
             fill_is_3d: false,
             pick_tris: Vec::new(),
             pick_tris_low: Vec::new(),

src/modules/draw/modify/trim.rs

@@ -3059,6 +3059,7 @@ fn collect_runs(pts: &[[f64; 2]], take: &dyn Fn([f64; 2]) -> bool, out: &mut Vec
 /// Build a preview wire from a NaN-break point list.
 fn preview_wire(points: Vec<[f32; 3]>, color: [f32; 4], name: &str) -> WireModel {
     WireModel {
+        world_width: 0.0,
         fill_is_3d: false,
         pick_tris: Vec::new(),
         pick_tris_low: Vec::new(),

src/modules/layout/mview.rs

@@ -81,6 +81,7 @@ impl CadCommand for MviewCommand {
         let pt = pt.as_vec3();
         let c1 = self.corner1?;
         Some(WireModel {
+            world_width: 0.0,
             fill_is_3d: false,
             pick_tris: Vec::new(),
             pick_tris_low: Vec::new(),

src/modules/model/primitive_cmd.rs

@@ -305,6 +305,7 @@ inventory::submit!(crate::command::CommandRegistration {
 
 fn wire(name: &str, points: Vec<[f32; 3]>) -> WireModel {
     WireModel {
+        world_width: 0.0,
         fill_is_3d: false,
         pick_tris: Vec::new(),
         pick_tris_low: Vec::new(),

src/modules/view/plot_window.rs

@@ -48,6 +48,7 @@ impl CadCommand for PlotWindowCommand {
         let p1 = self.p1?.as_vec3();
         // Draw the selection rectangle.
         Some(WireModel {
+            world_width: 0.0,
             fill_is_3d: false,
             pick_tris: Vec::new(),
             pick_tris_low: Vec::new(),

src/modules/view/zoom_window.rs

@@ -65,6 +65,7 @@ impl CadCommand for ZoomWindowCommand {
         let max = p1.max(pt);
         // Draw a rectangle preview
         Some(WireModel {
+            world_width: 0.0,
             fill_is_3d: false,
             pick_tris: Vec::new(),
             pick_tris_low: Vec::new(),

src/scene/cache/block_cache.rs

@@ -325,6 +325,12 @@ fn build_defn(
                 subs.push(LocalSub::Nested(build_nested_ref(nested_ins, doc, bg_color)));
             }
             _ => {
+                // A wide polyline inside a block keeps its thin centre-line
+                // here (`LocalWire` carries no `world_width`, and `finalize`
+                // rebuilds every block wire with `world_width: 0.0`); its band
+                // is drawn by the hatch pipeline (`push_block_wide_fills`),
+                // which transforms with the block instance so the band scales
+                // correctly. The shader band is a top-level-entity path only.
                 for lw in tessellate_sub_local(doc, entity, anno_scale, bg_color) {
                     subs.push(LocalSub::Wire(lw));
                 }
@@ -848,6 +854,7 @@ impl Batches {
                 // the cached defn.
                 let color = crate::scene::view::render::adapt_to_bg(b.color, bg_color);
                 WireModel {
+                    world_width: 0.0,
                     fill_is_3d: false,
                     pick_tris: b.pick_tris,
                     pick_tris_low: b.pick_tris_low,

src/scene/convert/tess.rs

@@ -650,6 +650,7 @@ pub(crate) fn tessellate_entity(
             (ins.insert_point.z) as f32,
         );
         let marker = WireModel {
+            world_width: 0.0,
             fill_is_3d: false,
             pick_tris: Vec::new(),
             pick_tris_low: Vec::new(),
@@ -1029,6 +1030,7 @@ fn lod_stub_wire(
     // LOD boundary. #19.
     let stored_color = if selected { WireModel::SELECTED } else { color };
     WireModel {
+        world_width: 0.0,
         fill_is_3d: false,
         pick_tris: Vec::new(),
         pick_tris_low: Vec::new(),
@@ -1115,6 +1117,7 @@ fn lod_stub_wire_3d(
     }
     let stored_color = if selected { WireModel::SELECTED } else { color };
     WireModel {
+        world_width: 0.0,
         fill_is_3d: false,
         pick_tris: Vec::new(),
         pick_tris_low: Vec::new(),

src/scene/convert/tessellate.rs

@@ -370,6 +370,7 @@ pub fn tessellate(
                     None
                 };
                 elem_wires.push(WireModel {
+                    world_width: 0.0,
                     fill_is_3d: false,
                     pick_tris: Vec::new(),
                     pick_tris_low: Vec::new(),
@@ -660,6 +661,7 @@ pub fn tessellate(
                                         ftl.push(lo);
                                     }
                                     wires.push(WireModel {
+                                        world_width: 0.0,
                                         fill_is_3d: false,
                                         pick_tris: Vec::new(),
                                         pick_tris_low: Vec::new(),
@@ -697,6 +699,7 @@ pub fn tessellate(
                                         fpl.push(lo);
                                     }
                                     wires.push(WireModel {
+                                        world_width: 0.0,
                                         fill_is_3d: false,
                                         pick_tris: Vec::new(),
                                         pick_tris_low: Vec::new(),
@@ -741,6 +744,7 @@ pub fn tessellate(
                             low.push(ll);
                         }
                         wires.push(WireModel {
+                            world_width: 0.0,
                             fill_is_3d: false,
                             pick_tris: Vec::new(),
                             pick_tris_low: Vec::new(),
@@ -766,6 +770,7 @@ pub fn tessellate(
                         });
                     }
                     wires.push(WireModel {
+                        world_width: 0.0,
                         fill_is_3d: false,
                         pick_tris: Vec::new(),
                         pick_tris_low: Vec::new(),
@@ -821,6 +826,7 @@ pub fn tessellate(
                             (Vec::new(), Vec::new(), Vec::new())
                         };
                         out.push(WireModel {
+                            world_width: 0.0,
                             fill_is_3d: false,
                             pick_tris: Vec::new(),
                             pick_tris_low: Vec::new(),
@@ -858,6 +864,7 @@ pub fn tessellate(
                             (Vec::new(), Vec::new(), Vec::new())
                         };
                         out.push(WireModel {
+                            world_width: 0.0,
                             fill_is_3d: false,
                             pick_tris: Vec::new(),
                             pick_tris_low: Vec::new(),
@@ -892,6 +899,7 @@ pub fn tessellate(
                 // are empty → the early-return path above).
                 if !sdf_verts.is_empty() {
                     out.push(WireModel {
+                        world_width: 0.0,
                         fill_is_3d: false,
                         pick_tris: Vec::new(),
                         pick_tris_low: Vec::new(),
@@ -919,6 +927,7 @@ pub fn tessellate(
 
                 if out.is_empty() {
                     out.push(WireModel {
+                        world_width: 0.0,
                         fill_is_3d: false,
                         pick_tris: Vec::new(),
                         pick_tris_low: Vec::new(),
@@ -968,6 +977,7 @@ pub fn tessellate(
                             .map(|[kx, ky, kz]| [kx, ky, kz])
                             .collect();
                         return vec![WireModel {
+                            world_width: 0.0,
                             fill_is_3d: false,
                             pick_tris: Vec::new(),
                             pick_tris_low: Vec::new(),
@@ -1016,6 +1026,7 @@ pub fn tessellate(
                         .map(|[x, y, z]| [x, y, z])
                         .collect();
                     return vec![WireModel {
+                        world_width: 0.0,
                         fill_is_3d: false,
                         pick_tris: Vec::new(),
                         pick_tris_low: Vec::new(),
@@ -1052,9 +1063,12 @@ pub fn tessellate(
                         .into_iter()
                         .map(|[x, y, z]| [x, y, z])
                         .collect();
-                    // A wide polyline arrives here: its band is pick geometry.
+                    // A wide polyline arrives here: the shader expands this
+                    // centre-line to `world_width` so the band IS the wire (the
+                    // linetype dashes it); the band also backs pick.
                     let (pick_tris, pick_tris_low) = points_to_ds(te.pick_tris);
                     return vec![WireModel {
+                        world_width: lwpolyline_band_width(entity),
                         fill_is_3d: false,
                         pick_tris,
                         pick_tris_low,
@@ -1140,6 +1154,7 @@ pub fn tessellate(
                         (Vec::new(), Vec::new(), Vec::new())
                     };
                     out.push(WireModel {
+                        world_width: 0.0,
                         fill_is_3d: false,
                         pick_tris,
                         pick_tris_low,
@@ -1176,6 +1191,7 @@ pub fn tessellate(
                         (Vec::new(), Vec::new(), Vec::new())
                     };
                     out.push(WireModel {
+                        world_width: 0.0,
                         pick_tris: Vec::new(),
                         pick_tris_low: Vec::new(),
             dash_from_start: false,
@@ -1203,6 +1219,7 @@ pub fn tessellate(
 
                 if out.is_empty() {
                     out.push(WireModel {
+                        world_width: 0.0,
                         fill_is_3d: false,
                         pick_tris: Vec::new(),
                         pick_tris_low: Vec::new(),
@@ -1239,9 +1256,11 @@ pub fn tessellate(
                     .into_iter()
                     .map(|[x, y, z]| [x, y, z])
                     .collect();
-                // A wide polyline with PLINEGEN=0 arrives here.
+                // A wide polyline with PLINEGEN=0 arrives here: same shader-band
+                // treatment as the Contour arm, restarting the dash per segment.
                 let (pick_tris, pick_tris_low) = points_to_ds(te.pick_tris);
                 return vec![WireModel {
+                    world_width: lwpolyline_band_width(entity),
                     fill_is_3d: false,
                     pick_tris,
                     pick_tris_low,
@@ -1310,6 +1329,7 @@ pub fn tessellate(
     let snap_pts: Vec<(glam::DVec3, SnapHint)> =
         snap_pts.into_iter().map(|(p, h)| (p.as_dvec3(), h)).collect();
     vec![WireModel {
+        world_width: 0.0,
         fill_is_3d: false,
         pick_tris: Vec::new(),
         pick_tris_low: Vec::new(),
@@ -1489,6 +1509,29 @@ pub(crate) fn entity_z(entity: &EntityType) -> f32 {
     }
 }
 
+/// Band width (drawing units) of a wide LwPolyline whose flat band is drawn by
+/// expanding its centre-line wire in the shader. `0.0` = a zero-width polyline
+/// or a non-LwPolyline (a normal screen-pixel wire). A thickness-extruded
+/// polyline is excluded: its band becomes a 3-D tube (`thick_wide_band`), not a
+/// flat shader band. A tapering polyline (per-vertex start/end widths) collapses
+/// to its widest edge — the shader carries one width per wire.
+fn lwpolyline_band_width(entity: &EntityType) -> f32 {
+    match entity {
+        EntityType::LwPolyline(p) if p.thickness.abs() <= 1e-10 => {
+            let mut w = p.constant_width;
+            for v in &p.vertices {
+                w = w.max(v.start_width).max(v.end_width);
+            }
+            if w > 1e-9 {
+                w as f32
+            } else {
+                0.0
+            }
+        }
+        _ => 0.0,
+    }
+}
+
 // ── Fallback geometry (Viewport, Insert, Hatch outline, Ole2Frame) ───────
 //
 // Per-entity blocks have moved to their respective `entities/*.rs` files

src/scene/entity.rs

@@ -691,15 +691,14 @@ impl Scene {
         // Wide LWPolyline and Polyline2D fills
         for entity in self.document.entities() {
             let (common, fill_origin, fills) = match entity {
-                // A thickened wide LwPolyline becomes a 3-D tube: its bottom cap
-                // is drawn as a real depth-tested surface by the tessellator, not
-                // as this flat 2-D band (which, having only draw-order depth,
-                // would show through the tube walls in a 3-D view).
-                EntityType::LwPolyline(pl) if pl.thickness.abs() > 1e-10 => continue,
-                EntityType::LwPolyline(pl) => {
-                    let (o, f) = crate::entities::lwpolyline::wide_fills(pl);
-                    (&pl.common, o, f)
-                }
+                // A wide LwPolyline no longer draws its band here: the shader
+                // expands the centre-line wire to `world_width` (a real
+                // depth-tested band that also carries the linetype dash), so a
+                // second flat 2-D band with only draw-order depth would double
+                // it and show through 3-D geometry. A thickened one is likewise
+                // a 3-D tube built by the tessellator. Its band still backs pick
+                // (`pick_tris`), just not this fill.
+                EntityType::LwPolyline(_) => continue,
                 EntityType::Polyline2D(pl) => {
                     let (o, f) = crate::entities::polyline::wide_fills(pl);
                     (&pl.common, o, f)

src/scene/model/wire_model.rs

@@ -54,6 +54,12 @@ pub struct WireModel {
     pub pattern: [f32; 8],
     /// Rendered line width in screen pixels (half-width = line_weight_px / 2).
     pub line_weight_px: f32,
+    /// World-space band width (drawing units). `0.0` = a normal wire whose
+    /// width comes from `line_weight_px` (screen pixels). Non-zero = a wide
+    /// polyline: the shader expands this centre-line to `world_width` world
+    /// units (scaling with zoom) so the band IS the wire — the linetype dash
+    /// pattern then applies to the band instead of a separate hatch fill.
+    pub world_width: f32,
     /// ACI color index (1-255).  0 means true-color or unknown (no CTB lookup).
     pub aci: u8,
     /// Pre-baked snap candidates (Center, Node, Quadrant, Insertion).
@@ -173,6 +179,7 @@ impl WireModel {
     /// Create a solid wire (no dash pattern, 1px weight).
     pub fn solid(name: String, points: Vec<[f32; 3]>, color: [f32; 4], selected: bool) -> Self {
         Self {
+            world_width: 0.0,
             fill_is_3d: false,
             pick_tris: Vec::new(),
             pick_tris_low: Vec::new(),
@@ -394,6 +401,7 @@ impl Default for WireModel {
             pattern_length: 0.0,
             pattern: [0.0; 8],
             line_weight_px: 1.0,
+            world_width: 0.0,
             aci: 0,
             snap_pts: Vec::new(),
             tangent_geoms: Vec::new(),

src/scene/pipeline/wire_gpu.rs

@@ -119,7 +119,11 @@ pub struct WireConst {
     pub draw_depth: f32,
     pub align_end: f32,
     pub align_total: f32,
-    pub _pad0: f32,
+    /// World-space half-width for a wide-polyline band. `0.0` = a normal wire
+    /// (uses `half_width`, screen pixels). Non-zero = the vertex shader expands
+    /// the quad by `world_half_width / world_per_pixel` so the band tracks zoom
+    /// in drawing units.
+    pub world_half_width: f32,
     pub _pad1: f32,
     pub _pad2: f32,
 }
@@ -171,6 +175,9 @@ pub struct WireInstance {
     /// and the total wire length. `align_total == 0.0` = not aligned.
     pub align_end: f32,
     pub align_total: f32,
+    /// World-space half-width for a wide-polyline band (see `WireConst`). `0.0`
+    /// = a normal wire (uses `half_width`, screen pixels).
+    pub world_half_width: f32,
 }
 
 #[cfg(target_arch = "wasm32")]
@@ -194,6 +201,7 @@ impl WireInstance {
             wgpu::VertexAttribute { offset: std::mem::offset_of!(WireInstance, pos_b_low) as u64,      shader_location: 11, format: wgpu::VertexFormat::Float32x3 },
             wgpu::VertexAttribute { offset: std::mem::offset_of!(WireInstance, align_end) as u64,      shader_location: 12, format: wgpu::VertexFormat::Float32   },
             wgpu::VertexAttribute { offset: std::mem::offset_of!(WireInstance, align_total) as u64,    shader_location: 13, format: wgpu::VertexFormat::Float32   },
+            wgpu::VertexAttribute { offset: std::mem::offset_of!(WireInstance, world_half_width) as u64, shader_location: 14, format: wgpu::VertexFormat::Float32 },
         ];
         wgpu::VertexBufferLayout {
             array_stride: std::mem::size_of::<WireInstance>() as u64,
@@ -403,6 +411,7 @@ fn emit_wire_instances(wire: &WireModel, color: [f32; 4], draw_depth: f32) -> Ve
             draw_depth,
             align_end,
             align_total,
+            world_half_width: wire.world_width * 0.5,
         });
     }
     instances
@@ -427,7 +436,7 @@ pub(crate) fn emit_wire_native(
         draw_depth,
         align_end,
         align_total,
-        _pad0: 0.0,
+        world_half_width: wire.world_width * 0.5,
         _pad1: 0.0,
         _pad2: 0.0,
     };

src/scene/text/complex_lt.rs

@@ -305,6 +305,7 @@ pub fn apply_along(
         .into_iter()
         .filter(|s| s.len() >= 2)
         .map(|pts| WireModel {
+            world_width: 0.0,
             fill_is_3d: false,
             pick_tris: Vec::new(),
             pick_tris_low: Vec::new(),
@@ -344,6 +345,7 @@ pub fn apply_along(
             xy = xy.max(y);
         }
         out.push(WireModel {
+            world_width: 0.0,
             fill_is_3d: false,
             pick_tris: Vec::new(),
             pick_tris_low: Vec::new(),

src/shaders/wire.wgsl

@@ -59,6 +59,8 @@ struct InstanceIn {
     // "A"-type endpoint alignment: end-dash length + total wire length.
     @location(12) align_end:     f32,
     @location(13) align_total:   f32,
+    // World-space half-width for a wide-polyline band. 0 = normal wire.
+    @location(14) world_half_width: f32,
 }
 
 // Draw-order depth bias: shifts clip-space z so 2D entities of different
@@ -129,8 +131,18 @@ struct VertexOut {
     // Select the clip-space position for this vertex's endpoint.
     let clip_pos = mix(clip_a, clip_b, which_end);
 
-    // LWDISPLAY off → collapse to a 1-pixel-wide line (half_width = 0.5).
-    let hw = select(0.5, in.half_width, u.lwdisplay_enable > 0.5);
+    // A wide polyline carries its band width in world units: expand the quad by
+    // `world_half_width / world_per_pixel` (pixels) so the band tracks zoom. A
+    // normal wire (world_half_width == 0) uses the screen-pixel half-width,
+    // honouring the LWDISPLAY toggle (off → collapse to a 1-pixel line).
+    var hw: f32;
+    if in.world_half_width > 0.0 {
+        // Clamp to a half-pixel so a zoomed-out band never drops below a
+        // hairline (its centre-line) instead of vanishing.
+        hw = max(in.world_half_width / u.world_per_pixel, 0.5);
+    } else {
+        hw = select(0.5, in.half_width, u.lwdisplay_enable > 0.5);
+    }
 
     // Offset in clip space (multiply by w to un-apply perspective division).
     let ndc_offset = perp_ndc * hw * side;

src/shaders/wire_indexed.wgsl

@@ -30,7 +30,7 @@ struct WireConst {
     draw_depth:     f32,
     align_end:      f32,
     align_total:    f32,
-    _pad0:          f32,
+    world_half_width: f32,
     _pad1:          f32,
     _pad2:          f32,
 }
@@ -93,7 +93,18 @@ struct VertexOut {
 
     let clip_pos = mix(clip_a, clip_b, which_end);
 
-    let hw = select(0.5, c.half_width, u.lwdisplay_enable > 0.5);
+    // A wide polyline carries its band width in world units: expand the quad
+    // by `world_half_width / world_per_pixel` (screen pixels) so the band grows
+    // and shrinks with zoom. A normal wire (world_half_width == 0) uses the
+    // screen-pixel half-width, honouring the LWDISPLAY toggle.
+    var hw: f32;
+    if c.world_half_width > 0.0 {
+        // Clamp to a half-pixel so a zoomed-out band never drops below a
+        // hairline (its centre-line) instead of vanishing.
+        hw = max(c.world_half_width / u.world_per_pixel, 0.5);
+    } else {
+        hw = select(0.5, c.half_width, u.lwdisplay_enable > 0.5);
+    }
 
     let ndc_offset = perp_ndc * hw * side;
     let final_clip = clip_pos + vec4<f32>(ndc_offset * clip_pos.w, 0.0, 0.0);