From a767e2240cc299514856bdca88e7f0d856ca1d4d Mon Sep 17 00:00:00 2001
From: Justin Lin <caterpillar@openhome.cc>
Date: Sat, 4 May 2019 09:11:51 +0800
Subject: [PATCH] add comment

---
 src/path_extrude.scad | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/src/path_extrude.scad b/src/path_extrude.scad
index 3378995b..77c56d2a 100644
--- a/src/path_extrude.scad
+++ b/src/path_extrude.scad
@@ -13,6 +13,10 @@ include <__private__/__to3d.scad>;
 include <__private__/__angy_angz.scad>;
 include <__private__/__m_multiply.scad>;
 
+// Becuase of improving the performance, this module requires m_rotation.scad. 
+// For backward compatibility, I directly include m_rotation here.
+include <m_rotation.scad>;
+
 module path_extrude(shape_pts, path_pts, triangles = "SOLID", twist = 0, scale = 1.0, closed = false) {
     // pre-process parameters
     function scale_pts(pts, s) = [