Complete 2D solid workflow

src/scene/convert/tessellate.rs

@@ -1260,7 +1260,7 @@ pub fn tessellate(
                         | EntityType::PolyfaceMesh(_)
                         | EntityType::PolygonMesh(_)
                         | EntityType::Mesh(_)
-                );
+                ) || matches!(entity, EntityType::Solid(solid) if solid.thickness.abs() > 1.0e-10);
                 // 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

src/scene/entity.rs

@@ -2158,8 +2158,8 @@ impl Scene {
     }
 
     /// Build a solid-fill HatchModel for a DXF Solid entity.
-    /// Conventional DXF SOLID corners use Z-order; legacy entities may already
-    /// be in perimeter order. Use the same non-crossing resolver as wire fill.
+    /// SOLID corners use Z-order. Preserve it in the projected hatch as well so
+    /// intentionally crossing geometry is not silently rewritten.
     pub(super) fn solid_hatch_model(solid: &DxfSolid, color: [f32; 4]) -> HatchModel {
         // Keep the corners in f64 until the AABB centre is known, then store
         // each as a small f32 offset from it — same precision-preserving anchor
@@ -2167,7 +2167,7 @@ impl Scene {
         // to f32 costs ~0.06 units of resolution at UTM magnitudes (~1e6), so
         // the quad snapped to a grid and the fill drifted off its outline.
         let wcs = crate::entities::solid::wcs_corners(solid);
-        let order = crate::entities::solid::perimeter_indices(&wcs);
+        let order = [0, 1, 3, 2];
         let corners: [[f64; 2]; 4] = order.map(|index| [wcs[index][0], wcs[index][1]]);
         let mut min = [f64::INFINITY; 2];
         let mut max = [f64::NEG_INFINITY; 2];

src/scene/pipeline/face3d_gpu.rs

@@ -22,6 +22,20 @@ use crate::scene::model::wire_model::WireModel;
 use iced::wgpu;
 use iced::wgpu::util::DeviceExt;
 
+fn planar_solid_faces_view(wire: &WireModel, view_dir: glam::Vec3) -> bool {
+    if !wire.fill_is_2d_solid || wire.fill_is_3d {
+        return true;
+    }
+    let view = view_dir.normalize_or_zero();
+    wire.fill_tris.chunks_exact(3).any(|triangle| {
+        let first = glam::Vec3::from_array(triangle[0]);
+        let second = glam::Vec3::from_array(triangle[1]);
+        let third = glam::Vec3::from_array(triangle[2]);
+        let normal = (second - first).cross(third - first).normalize_or_zero();
+        normal.length_squared() > 0.0 && normal.dot(view).abs() >= 1.0 - 1.0e-5
+    })
+}
+
 // ── Vertex layout ──────────────────────────────────────────────────────────
 
 #[repr(C)]
@@ -149,6 +163,7 @@ impl Face3DGpu {
         all_wires: &[WireModel],
         keep_3d_mesh_fills: bool,
         show_2d_solid_fills: bool,
+        view_dir: glam::Vec3,
         depth_map: &rustc_hash::FxHashMap<u64, [f32; 2]>,
     ) -> Self {
         let depth_of =
@@ -200,6 +215,9 @@ impl Face3DGpu {
             if !show_2d_solid_fills && wire.fill_is_2d_solid {
                 continue;
             }
+            if !planar_solid_faces_view(wire, view_dir) {
+                continue;
+            }
             // A real 3-D surface fill (PolyfaceMesh / PolygonMesh) carries a
             // double-single low residual paired with `fill_tris` — it lives at
             // true world coordinates and must keep its real depth. 2-D fills
@@ -259,6 +277,7 @@ impl Face3DGpu {
             all_wires,
             keep_3d_mesh_fills,
             show_2d_solid_fills,
+            view_dir,
             depth_map,
         );
         Self {
@@ -275,6 +294,7 @@ fn upload_block_chunks(
     wires: &[WireModel],
     keep_3d_mesh_fills: bool,
     show_2d_solid_fills: bool,
+    view_dir: glam::Vec3,
     depth_map: &rustc_hash::FxHashMap<u64, [f32; 2]>,
 ) -> (Vec<BlockFace3DChunk>, Vec<BlockFace3DChunk>) {
     let mut slots = rustc_hash::FxHashMap::default();
@@ -285,6 +305,7 @@ fn upload_block_chunks(
         };
         if wire.fill_tris.is_empty()
             || (!show_2d_solid_fills && wire.fill_is_2d_solid)
+            || !planar_solid_faces_view(wire, view_dir)
             || (wire.fill_is_3d && !keep_3d_mesh_fills)
         {
             continue;

src/scene/pipeline/mod.rs

@@ -312,12 +312,12 @@ pub struct Pipeline {
     /// a pick bumps only `selection_generation`, refreshing the overlay without
     /// touching the main wire buffers.
     pub cached_selection: (u64, u64),
-    /// `(wire_content_id, face3d_fill_active, show_2d_solid_fills)` the Face3D
+    /// `(wire_content_id, face3d_fill_active, show_2d_solid_fills, view_dir)` the Face3D
     /// edge/fill buffers were uploaded for. A stable content id avoids retaining
     /// the resident wire Arc:
     /// that Arc must stay uniquely owned by Scene so a small edit can splice it
     /// in place instead of rebuilding the whole drawing.
-    pub cached_face3d_key: (u64, bool, bool),
+    pub cached_face3d_key: (u64, bool, bool, [u32; 3]),
     /// Handle → indices into the resident wire set, built once per wire upload
     /// (when `cached_wire_id` changes). Lets the selection/hover xray overlay
     /// gather just the highlighted entity's wires (`O(highlighted)`) instead of
@@ -2323,7 +2323,7 @@ impl Pipeline {
             cached_epoch: (u64::MAX, u64::MAX, u64::MAX),
             cached_wire_id: u64::MAX,
             cached_selection: (u64::MAX, u64::MAX),
-            cached_face3d_key: (u64::MAX, false, false),
+            cached_face3d_key: (u64::MAX, false, false, [u32::MAX; 3]),
             wire_handle_index: std::sync::Arc::new(rustc_hash::FxHashMap::default()),
             render_sig: u64::MAX,
             skip_geometry: false,
@@ -3023,6 +3023,7 @@ impl Pipeline {
         all_wires: &[WireModel],
         wireframe_only: bool,
         show_2d_solid_fills: bool,
+        view_dir: glam::Vec3,
         depth_map: &rustc_hash::FxHashMap<u64, [f32; 2]>,
     ) {
         let perf_started = crate::perf::enabled().then(iced::time::Instant::now);
@@ -3056,6 +3057,7 @@ impl Pipeline {
                 all_wires,
                 keep_3d_mesh_fills,
                 show_2d_solid_fills,
+                view_dir,
                 depth_map,
             ));
         }

src/scene/view/render.rs

@@ -378,7 +378,7 @@ impl shader::Primitive for Primitive {
                 inner.cached_wire_id = u64::MAX;
                 inner.cached_selection = (u64::MAX, u64::MAX);
                 inner.cached_mesh_content_id = u64::MAX;
-                inner.cached_face3d_key = (u64::MAX, false, false);
+                inner.cached_face3d_key = (u64::MAX, false, false, [u32::MAX; 3]);
                 inner.cached_hatch_source = None;
                 inner.cached_preview_hatch_source = None;
                 inner.cached_wipeout_source = None;
@@ -484,6 +484,12 @@ impl shader::Primitive for Primitive {
             // the view toggle so 2D fills stay on even when the user picks
             // the Wireframe overlay style.
             let face3d_fill_active = fill_mode && !vp.view_wireframe;
+            let solid_fill_active = fill_mode && vp.show_2d_solid_fills;
+            let view_dir_key = [
+                vp.view_dir.x.to_bits(),
+                vp.view_dir.y.to_bits(),
+                vp.view_dir.z.to_bits(),
+            ];
             let fill_changed = inner.cached_fill_mode != fill_mode;
             let hatch_changed = inner
                 .cached_hatch_source
@@ -574,14 +580,16 @@ impl shader::Primitive for Primitive {
                     && !face_pass_unchanged);
             if face3d_changed
                 || face3d_fill_active != inner.cached_face3d_key.1
-                || vp.show_2d_solid_fills != inner.cached_face3d_key.2
+                || solid_fill_active != inner.cached_face3d_key.2
+                || view_dir_key != inner.cached_face3d_key.3
             {
                 inner.upload_face3d(
                     device,
                     &vp.face3d_wires[..],
                     &vp_wires[..],
                     !face3d_fill_active,
-                    vp.show_2d_solid_fills,
+                    solid_fill_active,
+                    vp.view_dir,
                     &draw_depths,
                 );
                 inner.cached_face3d_source = Some(Arc::clone(&vp.face3d_wires));
@@ -590,7 +598,8 @@ impl shader::Primitive for Primitive {
             inner.cached_face3d_key = (
                 vp.wire_content_id,
                 face3d_fill_active,
-                vp.show_2d_solid_fills,
+                solid_fill_active,
+                view_dir_key,
             );
             // Wire buffers are world-space, so a camera move alone doesn't
             // change them — only the view_proj uniform (uploaded every frame).