diff --git a/src/archimedean_spiral_extrude.scad b/src/archimedean_spiral_extrude.scad
index a229786a..f4e602e4 100644
--- a/src/archimedean_spiral_extrude.scad
+++ b/src/archimedean_spiral_extrude.scad
@@ -10,7 +10,7 @@
 
 use <archimedean_spiral.scad>;
 use <cross_sections.scad>;
-use <polysections.scad>;
+use <sweep.scad>;
 
 module archimedean_spiral_extrude(shape_pts, arm_distance, init_angle, point_distance, num_of_points, 
                                   rt_dir = "CT_CLK", twist = 0, scale = 1.0, triangles = "SOLID") {
@@ -32,7 +32,7 @@ module archimedean_spiral_extrude(shape_pts, arm_distance, init_angle, point_dis
 
     sections = cross_sections(shape_pts, points, angles, twist, scale);
 
-    polysections(
+    sweep(
         sections,
         triangles = triangles
     );
diff --git a/src/experimental/todo.txt b/src/experimental/todo.txt
index b5a52e38..07cf02b2 100644
--- a/src/experimental/todo.txt
+++ b/src/experimental/todo.txt
@@ -2,4 +2,8 @@
 - deprecate trianglate, use tri_ear_clipping.
 - sort supports a list of ints?
 - dedup px_xxx?
-- px_union, px_intersection, px_difference?
\ No newline at end of file
+- px_union, px_intersection, px_difference?
+
+Preview
+
+- sweep
\ No newline at end of file
diff --git a/src/golden_spiral_extrude.scad b/src/golden_spiral_extrude.scad
index 07265cfc..046cb2fe 100644
--- a/src/golden_spiral_extrude.scad
+++ b/src/golden_spiral_extrude.scad
@@ -10,7 +10,7 @@
 
 use <golden_spiral.scad>;
 use <cross_sections.scad>;
-use <polysections.scad>;
+use <sweep.scad>;
 
 module golden_spiral_extrude(shape_pts, from, to, point_distance, 
                              rt_dir = "CT_CLK", twist = 0, scale = 1.0, triangles = "SOLID") {
@@ -37,7 +37,7 @@ module golden_spiral_extrude(shape_pts, from, to, point_distance,
         scale = scale
     );
 
-    polysections(
+    sweep(
         sections,
         triangles = triangles
     );
diff --git a/src/helix_extrude.scad b/src/helix_extrude.scad
index f5a61f41..19049802 100644
--- a/src/helix_extrude.scad
+++ b/src/helix_extrude.scad
@@ -11,7 +11,7 @@
 use <__comm__/__frags.scad>;
 use <helix.scad>;
 use <cross_sections.scad>;
-use <polysections.scad>;
+use <sweep.scad>;
 
 module helix_extrude(shape_pts, radius, levels, level_dist, 
                      vt_dir = "SPI_DOWN", rt_dir = "CT_CLK", 
@@ -47,7 +47,7 @@ module helix_extrude(shape_pts, radius, levels, level_dist,
     
     sections = cross_sections(shape_pts, path_points, angles, twist, scale);
 
-    polysections(
+    sweep(
         sections,
         triangles = triangles
     );
diff --git a/src/path_extrude.scad b/src/path_extrude.scad
index 3f839871..57f27d8d 100644
--- a/src/path_extrude.scad
+++ b/src/path_extrude.scad
@@ -11,7 +11,7 @@
 use <__comm__/__to3d.scad>;
 use <__comm__/__angy_angz.scad>;
 use <rotate_p.scad>;
-use <polysections.scad>;
+use <sweep.scad>;
 use <matrix/m_rotation.scad>;
 
 module path_extrude(shape_pts, path_pts, triangles = "SOLID", twist = 0, scale = 1.0, closed = false, method = "AXIS_ANGLE") {
@@ -145,7 +145,7 @@ module path_extrude(shape_pts, path_pts, triangles = "SOLID", twist = 0, scale =
                 concat(sections, [sections[0]]) : // round-robin
                 sections;
         
-        polysections(
+        sweep(
             calculated_sections,
             triangles = triangles
         );   
@@ -192,7 +192,7 @@ module path_extrude(shape_pts, path_pts, triangles = "SOLID", twist = 0, scale =
                 concat(path_extrude_inner, [path_extrude_inner[0]]) : // round-robin
                 concat([section(pth_pts[0], pth_pts[1], 0)], path_extrude_inner);
 
-        polysections(
+        sweep(
             calculated_sections,
             triangles = triangles
         );   
diff --git a/src/ring_extrude.scad b/src/ring_extrude.scad
index b49de8d5..3e75b23e 100644
--- a/src/ring_extrude.scad
+++ b/src/ring_extrude.scad
@@ -11,7 +11,7 @@
 use <__comm__/__frags.scad>;
 use <__comm__/__ra_to_xy.scad>;
 use <cross_sections.scad>;
-use <polysections.scad>;
+use <sweep.scad>;
 
 module ring_extrude(shape_pts, radius, angle = 360, twist = 0, scale = 1.0, triangles = "SOLID") {
     if(twist == 0 && scale == 1.0) {
@@ -52,7 +52,7 @@ module ring_extrude(shape_pts, radius, angle = 360, twist = 0, scale = 1.0, tria
 
         sections = cross_sections(shape_pts, all_points, all_angles, twist, scale);
 
-        polysections(
+        sweep(
             sections,
             triangles = triangles
         );
diff --git a/src/sphere_spiral_extrude.scad b/src/sphere_spiral_extrude.scad
index 12e0e428..08346a46 100644
--- a/src/sphere_spiral_extrude.scad
+++ b/src/sphere_spiral_extrude.scad
@@ -10,7 +10,7 @@
 
 use <cross_sections.scad>;
 use <sphere_spiral.scad>;
-use <polysections.scad>;
+use <sweep.scad>;
 
 module sphere_spiral_extrude(shape_pts, radius, za_step, 
                              z_circles = 1, begin_angle = 0, end_angle = 0, vt_dir = "SPI_DOWN", rt_dir = "CT_CLK", 
@@ -36,7 +36,7 @@ module sphere_spiral_extrude(shape_pts, radius, za_step,
         shape_pts, points, angles, twist = twist, scale = scale
     );
 
-    polysections(
+    sweep(
         sections, 
         triangles = triangles
     );
diff --git a/src/experimental/sweep.scad b/src/sweep.scad
similarity index 94%
rename from src/experimental/sweep.scad
rename to src/sweep.scad
index bd92c979..5fdcfa5c 100644
--- a/src/experimental/sweep.scad
+++ b/src/sweep.scad
@@ -1,7 +1,3 @@
-/**
-    copy from polysections. sweep will replace polysections.
-**/
-
 use <util/reverse.scad>;
 
 module sweep(sections, triangles = "SOLID") {
@@ -81,7 +77,7 @@ module sweep(sections, triangles = "SOLID") {
             ); 
 
             // hook for testing
-            test_polysections_solid(v_pts, f_idxes, triangles);
+            test_sweep_solid(v_pts, f_idxes, triangles);
         } else {
             range_i = [0:leng_pts_sect - 1];
             first_idxes = [for(i = range_i) leng_pts_sect - 1 - i];  
@@ -98,7 +94,7 @@ module sweep(sections, triangles = "SOLID") {
             );   
 
             // hook for testing
-            test_polysections_solid(v_pts, f_idxes, triangles);             
+            test_sweep_solid(v_pts, f_idxes, triangles);             
         }
     }
 
@@ -176,7 +172,7 @@ module sweep(sections, triangles = "SOLID") {
             );      
 
             // hook for testing
-            test_polysections_solid(v_pts, f_idxes, triangles);                     
+            test_sweep_solid(v_pts, f_idxes, triangles);                     
         } else {
             first_idxes = first_idxes();
             last_idxes = last_idxes(half_leng_v_pts - half_leng_sect);
@@ -189,7 +185,7 @@ module sweep(sections, triangles = "SOLID") {
             ); 
 
             // hook for testing
-            test_polysections_solid(v_pts, f_idxes, triangles);              
+            test_sweep_solid(v_pts, f_idxes, triangles);              
         }
     }
     
@@ -243,6 +239,6 @@ module sweep(sections, triangles = "SOLID") {
 
 // override it to test
 
-module test_polysections_solid(points, faces, triangles) {
+module test_sweep_solid(points, faces, triangles) {
 
 }
\ No newline at end of file