fix(render): flag 2D overlay fills so they show in every view mode

A SOLID's filled quad and a dimension/MultiLeader text background are flat 2-D
overlays that should draw in wireframe and shaded alike, but face3d_gpu
classified fills by `!fill_tris_low.is_empty()` — and a 2-D fill at UTM scale
carries a double-single low residual for precision just like a real 3-D mesh
face. So the arrowhead fill and the "5;8" cyan text background were routed to
the 3-D buffer and only appeared in shaded mode, vanishing back to nothing on
return to wireframe.

WireModel now carries an explicit `fill_is_3d`: true only for a real surface
(PolyfaceMesh / PolygonMesh face, set in the tessellator), false for every flat
overlay fill. face3d_gpu classifies on the flag, so 2-D fills stay in the
always-visible buffer while keeping their low residual (and UTM precision).

Verified on budweiser: the `_BoxFilled` arrow SOLID and the dim '5;8' MTEXT
background both tessellate with fill_is_3d = false.

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 {
+                                    fill_is_3d: false,
                                     pick_tris: Vec::new(),
                                     pick_tris_low: Vec::new(),
             dash_from_start: false,
@@ -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 {
+                                fill_is_3d: false,
                                 pick_tris: Vec::new(),
                                 pick_tris_low: Vec::new(),
             dash_from_start: false,

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

src/entities/leader.rs

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

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 {
+            fill_is_3d: false,
             pick_tris: Vec::new(),
             pick_tris_low: Vec::new(),
             dash_from_start: false,
@@ -1693,6 +1694,7 @@ impl MultiLeaderTess for MultiLeader {
                         xy = xy.max(y);
                     }
                     wires.push(WireModel {
+                        fill_is_3d: false,
                         pick_tris: Vec::new(),
                         pick_tris_low: Vec::new(),
                         dash_from_start: false,
@@ -1760,6 +1762,7 @@ impl MultiLeaderTess for MultiLeader {
                         wcs_corners[3],
                     ];
                     wires.push(WireModel {
+                        fill_is_3d: false,
                         pick_tris: Vec::new(),
                         pick_tris_low: Vec::new(),
             dash_from_start: false,
@@ -1795,6 +1798,7 @@ impl MultiLeaderTess for MultiLeader {
                         wcs_corners[0],
                     ];
                     wires.push(WireModel {
+                        fill_is_3d: false,
                         pick_tris: Vec::new(),
                         pick_tris_low: Vec::new(),
             dash_from_start: false,

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 {
+                fill_is_3d: false,
                 pick_tris: Vec::new(),
                 pick_tris_low: Vec::new(),
             dash_from_start: false,

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 {
+            fill_is_3d: false,
             pick_tris: Vec::new(),
             pick_tris_low: Vec::new(),
             dash_from_start: false,
@@ -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 {
+        fill_is_3d: false,
         pick_tris: Vec::new(),
         pick_tris_low: Vec::new(),
             dash_from_start: false,

src/modules/annotate/angular_dim.rs

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

src/modules/annotate/diameter_dim.rs

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

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 {
+            fill_is_3d: false,
             pick_tris: Vec::new(),
             pick_tris_low: Vec::new(),
             dash_from_start: false,

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 {
+            fill_is_3d: false,
             pick_tris: Vec::new(),
             pick_tris_low: Vec::new(),
             dash_from_start: false,

src/modules/annotate/dimjogline.rs

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

src/modules/annotate/dimtedit.rs

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

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 {
+        fill_is_3d: false,
         pick_tris: Vec::new(),
         pick_tris_low: Vec::new(),
             dash_from_start: false,

src/modules/annotate/linear_dim.rs

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

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 {
+        fill_is_3d: false,
         pick_tris: Vec::new(),
         pick_tris_low: Vec::new(),
             dash_from_start: false,

src/modules/annotate/mleader_edit.rs

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

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 {
+        fill_is_3d: false,
         pick_tris: Vec::new(),
         pick_tris_low: Vec::new(),
             dash_from_start: false,

src/modules/annotate/qdim.rs

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

src/modules/annotate/radius_dim.rs

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

src/modules/annotate/table_cmd.rs

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

src/modules/annotate/tolerance_cmd.rs

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

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 {
+            fill_is_3d: false,
             pick_tris: Vec::new(),
             pick_tris_low: Vec::new(),
             dash_from_start: false,

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 {
+            fill_is_3d: false,
             pick_tris: Vec::new(),
             pick_tris_low: Vec::new(),
             dash_from_start: false,

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 {
+            fill_is_3d: false,
             pick_tris: Vec::new(),
             pick_tris_low: Vec::new(),
             dash_from_start: false,

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 {
+            fill_is_3d: false,
             pick_tris: Vec::new(),
             pick_tris_low: Vec::new(),
             dash_from_start: false,
@@ -179,6 +180,7 @@ impl CadCommand for XLineCommand {
         let far_pos = base + dir * DISPLAY_EXTENT;
         let far_neg = base - dir * DISPLAY_EXTENT;
         Some(WireModel {
+            fill_is_3d: false,
             pick_tris: Vec::new(),
             pick_tris_low: Vec::new(),
             dash_from_start: false,

src/modules/draw/draw/revcloud.rs

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

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 {
+                    fill_is_3d: false,
                     pick_tris: Vec::new(),
                     pick_tris_low: Vec::new(),
             dash_from_start: false,
@@ -160,6 +161,7 @@ impl CadCommand for WipeoutCommand {
                     self.poly_pts[0].z as f32,
                 ]);
                 Some(WireModel {
+                    fill_is_3d: false,
                     pick_tris: Vec::new(),
                     pick_tris_low: Vec::new(),
             dash_from_start: false,

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 {
+            fill_is_3d: false,
             pick_tris: Vec::new(),
             pick_tris_low: Vec::new(),
             dash_from_start: false,

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 {
+            fill_is_3d: false,
             pick_tris: Vec::new(),
             pick_tris_low: Vec::new(),
             dash_from_start: false,

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 {
+            fill_is_3d: false,
             pick_tris: Vec::new(),
             pick_tris_low: Vec::new(),
             dash_from_start: false,

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 {
+        fill_is_3d: false,
         pick_tris: Vec::new(),
         pick_tris_low: Vec::new(),
         dash_from_start: false,

src/modules/layout/mview.rs

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

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 {
+        fill_is_3d: false,
         pick_tris: Vec::new(),
         pick_tris_low: Vec::new(),
             dash_from_start: false,

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 {
+            fill_is_3d: false,
             pick_tris: Vec::new(),
             pick_tris_low: Vec::new(),
             dash_from_start: false,

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 {
+            fill_is_3d: false,
             pick_tris: Vec::new(),
             pick_tris_low: Vec::new(),
             dash_from_start: false,

src/scene/cache/block_cache.rs

@@ -842,6 +842,7 @@ impl Batches {
                 // the cached defn.
                 let color = crate::scene::view::render::adapt_to_bg(b.color, bg_color);
                 WireModel {
+                    fill_is_3d: false,
                     pick_tris: b.pick_tris,
                     pick_tris_low: b.pick_tris_low,
                     dash_from_start: false,

src/scene/convert/tess.rs

@@ -555,6 +555,7 @@ pub(crate) fn tessellate_entity(
             (ins.insert_point.z) as f32,
         );
         let marker = WireModel {
+            fill_is_3d: false,
             pick_tris: Vec::new(),
             pick_tris_low: Vec::new(),
             dash_from_start: false,
@@ -934,6 +935,7 @@ fn lod_stub_wire(
     // LOD boundary. #19.
     let stored_color = if selected { WireModel::SELECTED } else { color };
     WireModel {
+        fill_is_3d: false,
         pick_tris: Vec::new(),
         pick_tris_low: Vec::new(),
         dash_from_start: false,
@@ -1020,6 +1022,7 @@ fn lod_stub_wire_3d(
     }
     let stored_color = if selected { WireModel::SELECTED } else { color };
     WireModel {
+        fill_is_3d: false,
         pick_tris: Vec::new(),
         pick_tris_low: Vec::new(),
         dash_from_start: false,

src/scene/convert/tessellate.rs

@@ -370,6 +370,7 @@ pub fn tessellate(
                     None
                 };
                 elem_wires.push(WireModel {
+                    fill_is_3d: false,
                     pick_tris: Vec::new(),
                     pick_tris_low: Vec::new(),
                     // MLINE dashes: A-type aligned, but the end-dash length is
@@ -652,6 +653,7 @@ pub fn tessellate(
                                         ftl.push(lo);
                                     }
                                     wires.push(WireModel {
+                                        fill_is_3d: false,
                                         pick_tris: Vec::new(),
                                         pick_tris_low: Vec::new(),
                                         dash_from_start: false,
@@ -689,6 +691,7 @@ pub fn tessellate(
                                         fpl.push(lo);
                                     }
                                     wires.push(WireModel {
+                                        fill_is_3d: false,
                                         pick_tris: Vec::new(),
                                         pick_tris_low: Vec::new(),
                                         dash_from_start: false,
@@ -733,6 +736,7 @@ pub fn tessellate(
                             low.push(ll);
                         }
                         wires.push(WireModel {
+                            fill_is_3d: false,
                             pick_tris: Vec::new(),
                             pick_tris_low: Vec::new(),
                             dash_from_start: false,
@@ -758,6 +762,7 @@ pub fn tessellate(
                         });
                     }
                     wires.push(WireModel {
+                        fill_is_3d: false,
                         pick_tris: Vec::new(),
                         pick_tris_low: Vec::new(),
                         dash_from_start: false,
@@ -813,6 +818,7 @@ pub fn tessellate(
                             (Vec::new(), Vec::new(), Vec::new())
                         };
                         out.push(WireModel {
+                            fill_is_3d: false,
                             pick_tris: Vec::new(),
                             pick_tris_low: Vec::new(),
             dash_from_start: false,
@@ -850,6 +856,7 @@ pub fn tessellate(
                             (Vec::new(), Vec::new(), Vec::new())
                         };
                         out.push(WireModel {
+                            fill_is_3d: false,
                             pick_tris: Vec::new(),
                             pick_tris_low: Vec::new(),
             dash_from_start: false,
@@ -884,6 +891,7 @@ pub fn tessellate(
                 // are empty → the early-return path above).
                 if !sdf_verts.is_empty() {
                     out.push(WireModel {
+                        fill_is_3d: false,
                         pick_tris: Vec::new(),
                         pick_tris_low: Vec::new(),
                         dash_from_start: false,
@@ -911,6 +919,7 @@ pub fn tessellate(
 
                 if out.is_empty() {
                     out.push(WireModel {
+                        fill_is_3d: false,
                         pick_tris: Vec::new(),
                         pick_tris_low: Vec::new(),
             dash_from_start: false,
@@ -960,6 +969,7 @@ pub fn tessellate(
                             .map(|[kx, ky, kz]| [kx, ky, kz])
                             .collect();
                         return vec![WireModel {
+                            fill_is_3d: false,
                             pick_tris: Vec::new(),
                             pick_tris_low: Vec::new(),
             dash_from_start: false,
@@ -1008,6 +1018,7 @@ pub fn tessellate(
                         .map(|[x, y, z]| [x, y, z])
                         .collect();
                     return vec![WireModel {
+                        fill_is_3d: false,
                         pick_tris: Vec::new(),
                         pick_tris_low: Vec::new(),
             dash_from_start: false,
@@ -1047,6 +1058,7 @@ pub fn tessellate(
                     // A wide polyline arrives here: its band is pick geometry.
                     let (pick_tris, pick_tris_low) = points_to_ds(te.pick_tris);
                     return vec![WireModel {
+                        fill_is_3d: false,
                         pick_tris,
                         pick_tris_low,
             dash_from_start: false,
@@ -1088,6 +1100,14 @@ pub fn tessellate(
                     .map(|[x, y, z]| [x, y, z])
                     .collect();
                 let (fill_tris, fill_tris_low) = points_to_ds(te.fill_tris);
+                // Only a real 3-D mesh surface (PolyfaceMesh / PolygonMesh) fill
+                // renders shaded-only with hidden-surface depth; every other
+                // `fill_tris` here (a SOLID's filled quad — e.g. a `_BoxFilled`
+                // arrowhead) is a flat 2-D overlay visible in every view mode.
+                let fill_is_3d = matches!(
+                    entity,
+                    EntityType::PolyfaceMesh(_) | EntityType::PolygonMesh(_)
+                );
                 // Thickness walls ride on the wire that carries their edges, not
                 // on a wire of their own: they are pick geometry for that entity,
                 // and `fill_tris` below deliberately splits off into a fill-only
@@ -1108,6 +1128,7 @@ pub fn tessellate(
                         (Vec::new(), Vec::new(), Vec::new())
                     };
                     out.push(WireModel {
+                        fill_is_3d: false,
                         pick_tris,
                         pick_tris_low,
             dash_from_start: false,
@@ -1166,11 +1187,13 @@ pub fn tessellate(
                         vp_scissor: None,
                         fill_tris,
                         fill_tris_low,
+                        fill_is_3d,
                     });
                 }
 
                 if out.is_empty() {
                     out.push(WireModel {
+                        fill_is_3d: false,
                         pick_tris: Vec::new(),
                         pick_tris_low: Vec::new(),
             dash_from_start: false,
@@ -1210,6 +1233,7 @@ pub fn tessellate(
                 // A wide polyline with PLINEGEN=0 arrives here.
                 let (pick_tris, pick_tris_low) = points_to_ds(te.pick_tris);
                 return vec![WireModel {
+                    fill_is_3d: false,
                     pick_tris,
                     pick_tris_low,
             dash_from_start: false,
@@ -1278,6 +1302,7 @@ pub fn tessellate(
     let snap_pts: Vec<(glam::DVec3, SnapHint)> =
         snap_pts.into_iter().map(|(p, h)| (p.as_dvec3(), h)).collect();
     vec![WireModel {
+        fill_is_3d: false,
         pick_tris: Vec::new(),
         pick_tris_low: Vec::new(),
             dash_from_start: false,

src/scene/model/wire_model.rs

@@ -122,6 +122,13 @@ pub struct WireModel {
     /// exactly like `points` — no separate collector pass. The renderer
     /// gathers these across all wires into the text vertex buffer.
     pub text_verts: Vec<crate::scene::pipeline::text_gpu::TextVertex>,
+    /// `true` when [`fill_tris`] is a real 3-D surface (PolyfaceMesh /
+    /// PolygonMesh face) that must render with hidden-surface depth and only in
+    /// shaded modes. `false` for a flat 2-D overlay fill (SOLID arrowhead,
+    /// dimension / MultiLeader text background, greek-LOD text) that draws in
+    /// every view mode. The render pass can't infer this from `fill_tris_low`
+    /// alone — a 2-D fill at UTM scale carries a low residual too.
+    pub fill_is_3d: bool,
 }
 
 impl WireModel {
@@ -169,6 +176,7 @@ 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 {
+            fill_is_3d: false,
             pick_tris: Vec::new(),
             pick_tris_low: Vec::new(),
             text_verts: Vec::new(),
@@ -401,6 +409,7 @@ impl Default for WireModel {
             vp_scissor: None,
             fill_tris: Vec::new(),
             fill_tris_low: Vec::new(),
+            fill_is_3d: false,
             pick_tris: Vec::new(),
             pick_tris_low: Vec::new(),
         }

src/scene/pipeline/face3d_gpu.rs

@@ -186,12 +186,13 @@ impl Face3DGpu {
             // (text greek, MultiLeader / dimension backgrounds) deliberately
             // leave `fill_tris_low` empty and order by draw rank instead.
             //
-            // NOTE: classifying by `!points.is_empty()` is wrong here — the
-            // tessellator emits a mesh's edges and its fill as *separate*
-            // WireModels (points-only vs fill-only), so the fill model has no
-            // points and was being misrouted to the 2-D (draw-order-biased)
-            // buffer, which drew meshes in front of solids.
-            let is_3d_mesh_face = !wire.fill_tris_low.is_empty();
+            // NOTE: classifying by `!points.is_empty()` is wrong (a mesh emits
+            // its edges and its fill as *separate* WireModels), and so is
+            // `!fill_tris_low.is_empty()` — a 2-D overlay fill (SOLID arrowhead,
+            // dimension text background) at UTM scale carries a low residual
+            // too, and would be misrouted to the 3-D buffer where it only shows
+            // in shaded modes. The tessellator flags real surfaces explicitly.
+            let is_3d_mesh_face = wire.fill_is_3d;
             let [r, g, b, a] = wire.color;
             if is_3d_mesh_face {
                 if !keep_3d_mesh_fills {

src/scene/text/complex_lt.rs

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