diff --git a/cimery/crates/viewer/src/bridge_scene.rs b/cimery/crates/viewer/src/bridge_scene.rs
index d58d2d7..ba0c8c5 100644
--- a/cimery/crates/viewer/src/bridge_scene.rs
+++ b/cimery/crates/viewer/src/bridge_scene.rs
@@ -71,22 +71,22 @@ fn merge(meshes: Vec<Mesh>) -> Mesh {
 
 /// Build a complete bridge scene mesh using the provided kernel and parameters.
 pub fn build_bridge_scene<K: GeomKernel>(kernel: &K, p: &SceneParams) -> Result<Mesh, KernelError> {
-    let SPAN_M       = p.span_m;
-    let SPAN_MM      = (p.span_m * 1_000.0) as f32;
-    let N_GIRDERS    = p.girder_count.max(1).min(10);
-    let SPACING      = p.girder_spacing;
-    let GIRDER_H     = p.girder_height;
+    let span_m      = p.span_m;
+    let span_mm     = (p.span_m * 1_000.0) as f32;
+    let n_girders   = p.girder_count.max(1).min(10);
+    let spacing     = p.girder_spacing;
+    let girder_h    = p.girder_height;
     const BEARING_H: f32 = 60.0;      // mm
 
     let mut parts: Vec<Mesh> = Vec::new();
 
     // ── Girders ────────────────────────────────────────────────────────────────
-    for i in 0..N_GIRDERS {
-        let x = (i as f32 - (N_GIRDERS as f32 - 1.0) * 0.5) * SPACING;
+    for i in 0..n_girders {
+        let x = (i as f32 - (n_girders as f32 - 1.0) * 0.5) * spacing;
         let ir = GirderIR {
             id:                    FeatureId::new(),
             station_start:         0.0,
-            station_end:           SPAN_M,
+            station_end:           span_m,
             offset_from_alignment: x as f64,
             section_type:          SectionType::PscI,
             section: SectionParams::PscI(PscISectionParams::kds_standard()),
@@ -101,11 +101,11 @@ pub fn build_bridge_scene<K: GeomKernel>(kernel: &K, p: &SceneParams) -> Result<
 
     // ── Deck Slab ──────────────────────────────────────────────────────────────
     // KDS: min 220 mm, width = (N-1)*spacing + 2 × cantilever
-    let half_width = ((N_GIRDERS as f32 - 1.0) * SPACING) * 0.5 + 1_000.0; // 1 m cantilever
+    let half_width = ((n_girders as f32 - 1.0) * spacing) * 0.5 + 1_000.0; // 1 m cantilever
     let deck_ir = DeckSlabIR {
         id:            FeatureId::new(),
         station_start: 0.0,
-        station_end:   SPAN_M,
+        station_end:   span_m,
         width_left:    half_width as f64,
         width_right:   half_width as f64,
         thickness:     p.slab_thickness as f64,
@@ -115,16 +115,16 @@ pub fn build_bridge_scene<K: GeomKernel>(kernel: &K, p: &SceneParams) -> Result<
     };
     let mut deck_mesh = kernel.deck_slab_mesh(&deck_ir)?;
     deck_mesh.recolor(COL_DECK);
-    parts.push(translate(deck_mesh, 0.0, GIRDER_H + p.slab_thickness, 0.0));
+    parts.push(translate(deck_mesh, 0.0, girder_h + p.slab_thickness, 0.0));
 
     // ── Bearings ───────────────────────────────────────────────────────────────
     // 5 per abutment, one under each girder
-    for &z in &[0.0_f32, SPAN_MM] {
-        for i in 0..N_GIRDERS {
-            let x = (i as f32 - (N_GIRDERS as f32 - 1.0) * 0.5) * SPACING;
+    for &z in &[0.0_f32, span_mm] {
+        for i in 0..n_girders {
+            let x = (i as f32 - (n_girders as f32 - 1.0) * 0.5) * spacing;
             let bearing_ir = BearingIR {
                 id:                FeatureId::new(),
-                station:           if z < 1.0 { 0.0 } else { SPAN_M },
+                station:           if z < 1.0 { 0.0 } else { span_m },
                 bearing_type:      BearingType::Elastomeric,
                 plan_length:       350.0,
                 plan_width:        450.0,
@@ -139,10 +139,10 @@ pub fn build_bridge_scene<K: GeomKernel>(kernel: &K, p: &SceneParams) -> Result<
 
     // ── Abutments ──────────────────────────────────────────────────────────────
     let wing = WingWallIR { length: 5_000.0, height: 2_500.0, thickness: 500.0 };
-    let total_w = (N_GIRDERS as f64 - 1.0) * SPACING as f64 + 3_000.0;
-    let breast_wall_h = (GIRDER_H + BEARING_H) as f64;
+    let total_w = (n_girders as f64 - 1.0) * spacing as f64 + 3_000.0;
+    let breast_wall_h = (girder_h + BEARING_H) as f64;
 
-    for &(station, z) in &[(0.0f64, -800.0_f32), (SPAN_M, SPAN_MM)] {
+    for &(station, z) in &[(0.0f64, -800.0_f32), (span_m, span_mm)] {
         let abut_ir = AbutmentIR {
             id:                      FeatureId::new(),
             station,
diff --git a/cimery/crates/viewer/src/lib.rs b/cimery/crates/viewer/src/lib.rs
index 378fadb..117229a 100644
--- a/cimery/crates/viewer/src/lib.rs
+++ b/cimery/crates/viewer/src/lib.rs
@@ -284,8 +284,9 @@ impl RenderState {
             &*window,
             None, None, None,
         );
+        // egui renders 2D UI overlay — no depth buffer
         let egui_renderer = egui_wgpu::Renderer::new(
-            &device, format, Some(DEPTH_FORMAT), 1, false,
+            &device, format, None, 1, false,
         );
 
         RenderState {