diff --git a/src/cross_sections.scad b/src/cross_sections.scad
index ba4d9534..9ffc361a 100644
--- a/src/cross_sections.scad
+++ b/src/cross_sections.scad
@@ -8,8 +8,6 @@
 *
 **/
 
-use <__comm__/__to3d.scad>;
-
 use <matrix/m_scaling.scad>;
 use <matrix/m_translation.scad>;
 use <matrix/m_rotation.scad>;
@@ -17,24 +15,35 @@ use <matrix/m_rotation.scad>;
 function cross_sections(shape_pts, path_pts, angles, twist = 0, scale = 1.0) =
     let(
         len_path_pts_minus_one = len(path_pts) - 1,
-        sh_pts = len(shape_pts[0]) == 3 ? shape_pts : [for(p = shape_pts) __to3d(p)],
-        pth_pts = len(path_pts[0]) == 3 ? path_pts : [for(p = path_pts) __to3d(p)],
-        scale_step_vt = is_num(scale) ? 
-            [(scale - 1) / len_path_pts_minus_one, (scale - 1) / len_path_pts_minus_one] :
-            [(scale[0] - 1) / len_path_pts_minus_one, (scale[1] - 1) / len_path_pts_minus_one],
-        twist_step = twist / len_path_pts_minus_one
+        sh_pts = len(shape_pts[0]) == 3 ? [for(p = shape_pts) [each p, 1]] : [for(p = shape_pts) [each p, 0, 1]],
+        pth_pts = len(path_pts[0]) == 3 ? path_pts : [for(p = path_pts) [each p, 0]]
+    )
+    twist == 0 && scale == 1.0 ?
+    [
+        for(i = [0:len_path_pts_minus_one])
+        let(transform_m = m_translation(pth_pts[i]) * m_rotation(angles[i]))
+        [
+            for(p = sh_pts) 
+            let(transformed = transform_m * p)
+            [transformed.x, transformed.y, transformed.z]
+        ]
+    ] :
+    let(
+        twist_step = twist / len_path_pts_minus_one,
+        scale_step_vt = (is_num(scale) ? let(s = scale - 1) [s, s, 0] : ([each scale, 0] - [1, 1, 0])) / len_path_pts_minus_one,
+        one_s = [1, 1, 1]
     )
     [
-        for(i = 0; i <= len_path_pts_minus_one; i = i + 1)
+        for(i = [0:len_path_pts_minus_one])
         let(
             transform_m = m_translation(pth_pts[i]) * 
                           m_rotation(angles[i]) * 
                           m_rotation(twist_step * i) * 
-                          m_scaling([1 + scale_step_vt.x * i, 1 + scale_step_vt.y * i, 1])
+                          m_scaling(scale_step_vt * i + one_s)
         )
         [
             for(p = sh_pts) 
-            let(transformed = transform_m * [each p, 1])
+            let(transformed = transform_m * p)
             [transformed.x, transformed.y, transformed.z]
         ]
     ];