From 5c8c0b8139f99fcad663822574398d598fa0df45 Mon Sep 17 00:00:00 2001
From: Justin Lin <justin.sdk@gmail.com>
Date: Sat, 4 Dec 2021 10:17:13 +0800
Subject: [PATCH] update doc

---
 docs/lib3x-ptf_sphere.md | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/docs/lib3x-ptf_sphere.md b/docs/lib3x-ptf_sphere.md
index fe5c932b..d1293f48 100644
--- a/docs/lib3x-ptf_sphere.md
+++ b/docs/lib3x-ptf_sphere.md
@@ -15,7 +15,7 @@ Transforms a point inside a rectangle to a point of a sphere. It can create thin
 
 ## Examples
 
-    use <hull_polyline3d.scad>;
+    use <polyline_join.scad>;
     use <ptf/ptf_sphere.scad>;
 
     size = [20, 10];
@@ -34,12 +34,14 @@ Transforms a point inside a rectangle to a point of a sphere. It can create thin
 
     for(line = rows) {
         transformed = [for(p = line) ptf_sphere(size, p, radius, angle)];
-        hull_polyline3d(transformed, thickness = .5);
+        polyline_join(transformed)
+            sphere(.5);
     }
 
     for(line = columns) {
         transformed = [for(p = line) ptf_sphere(size, p, radius, angle)];
-        hull_polyline3d(transformed, thickness = .5);
+        polyline_join(transformed)
+            sphere(.5);
     }
 
 ![ptf_sphere](images/lib3x-ptf_sphere-2.JPG)