diff --git a/src/entities/common.rs b/src/entities/common.rs
index 136af184e..bdc2544db 100644
--- a/src/entities/common.rs
+++ b/src/entities/common.rs
@@ -818,6 +818,9 @@ pub(crate) fn triangulate_band_ring(ring: &[[f64; 3]]) -> Vec<[f64; 3]> {
 }
 
 pub(crate) fn wide_band_tris(origin: [f64; 2], fills: &[Vec<[f32; 2]>]) -> Vec<[f64; 3]> {
+    if fills.is_empty() {
+        return Vec::new();
+    }
     let mut total_verts = 0;
     for poly in fills {
         let n = poly.len();
@@ -925,8 +928,8 @@ pub(crate) fn tapered_band_points(
 ) -> (Vec<[f64; 3]>, Vec<f32>) {
     let n = verts.len();
     let seg_count = if is_closed { n } else { n.saturating_sub(1) };
-    let mut pts: Vec<[f64; 3]> = Vec::new();
-    let mut widths: Vec<f32> = Vec::new();
+    let mut pts: Vec<[f64; 3]> = Vec::with_capacity(seg_count + 1);
+    let mut widths: Vec<f32> = Vec::with_capacity(seg_count + 1);
     let mut push = |x: f64, y: f64, w: f32| {
         let (wx, wy, wz) = to_wcs(x, y);
         pts.push([wx, wy, wz]);
diff --git a/src/entities/lwpolyline.rs b/src/entities/lwpolyline.rs
index f1fe5ac84..2649321d4 100644
--- a/src/entities/lwpolyline.rs
+++ b/src/entities/lwpolyline.rs
@@ -1582,6 +1582,11 @@ pub(crate) fn wide_fills(pl: &acadrust::entities::LwPolyline) -> ([f64; 2], Vec<
     if n < 2 {
         return ([0.0; 2], vec![]);
     }
+    let is_wide = pl.constant_width > 1e-9
+        || verts.iter().any(|v| v.start_width > 1e-9 || v.end_width > 1e-9);
+    if !is_wide {
+        return ([0.0; 2], Vec::new());
+    }
     let origin = [verts[0].location.x, verts[0].location.y];
     let seg_count = if pl.is_closed { n } else { n - 1 };
     let mut out = Vec::new();
diff --git a/src/scene/convert/tessellate.rs b/src/scene/convert/tessellate.rs
index 485b192e9..75b7cf647 100644
--- a/src/scene/convert/tessellate.rs
+++ b/src/scene/convert/tessellate.rs
@@ -186,6 +186,9 @@ pub(crate) fn points_to_ds(
     let it = src.into_iter();
     let (lo, hi) = it.size_hint();
     let cap = hi.unwrap_or(lo);
+    if cap == 0 {
+        return (Vec::new(), Vec::new());
+    }
     let mut high = Vec::with_capacity(cap);
     let mut low = Vec::with_capacity(cap);
     for [x, y, z] in it {
@@ -327,9 +330,10 @@ fn split_mixed_polyline(
                 (sw, ew)
             };
 
-            let mut arc_pts = Vec::with_capacity(17);
-            let mut arc_widths = Vec::with_capacity(17);
             let n = 16;
+            let mut points = Vec::with_capacity(n + 1);
+            let mut points_low = Vec::with_capacity(n + 1);
+            let mut arc_widths = Vec::with_capacity(n + 1);
             let sweep = if end_angle >= start_angle {
                 end_angle - start_angle
             } else {
@@ -338,15 +342,15 @@ fn split_mixed_polyline(
             for s in 0..=n {
                 let frac = s as f64 / n as f64;
                 let ang = start_angle + frac * sweep;
-                let p = [
-                    center[0] + radius * (ang.cos() * axis_x[0] + ang.sin() * axis_y[0]),
-                    center[1] + radius * (ang.cos() * axis_x[1] + ang.sin() * axis_y[1]),
-                    center[2] + radius * (ang.cos() * axis_x[2] + ang.sin() * axis_y[2]),
-                ];
-                arc_pts.push(p);
+                let (sin_a, cos_a) = ang.sin_cos();
+                let x = center[0] + radius * (cos_a * axis_x[0] + sin_a * axis_y[0]);
+                let y = center[1] + radius * (cos_a * axis_x[1] + sin_a * axis_y[1]);
+                let z = center[2] + radius * (cos_a * axis_x[2] + sin_a * axis_y[2]);
+                let (h, l) = split_ds_xyz(x, y, z);
+                points.push(h);
+                points_low.push(l);
                 arc_widths.push(w_at_sa + (w_at_ea - w_at_sa) * frac as f32);
             }
-            let (points, points_low) = points_to_ds(arc_pts);
 
             let taper_widths = if (w_at_sa - w_at_ea).abs() > 1e-6 {
                 arc_widths