From 7518539350a0f54bf084c3545d34791e72e59f47 Mon Sep 17 00:00:00 2001
From: Justin Lin <justin.sdk@gmail.com>
Date: Sun, 20 Jun 2021 17:39:18 +0800
Subject: [PATCH] add swap_surface param

---
 src/surface/sf_thicken.scad | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/src/surface/sf_thicken.scad b/src/surface/sf_thicken.scad
index 3b7bd63f..c5d5c450 100644
--- a/src/surface/sf_thicken.scad
+++ b/src/surface/sf_thicken.scad
@@ -1,7 +1,7 @@
 use <sf_solidify.scad>;
 use <util/sum.scad>;
 
-module sf_thicken(points, thickness, direction = undef, slicing = "SLASH") {
+module sf_thicken(points, thickness, direction = undef, swap_surface = false, slicing = "SLASH") {
     function tri_normal(tri) =
         let(v = cross(tri[2] - tri[0], tri[1] - tri[0])) v / norm(v);    
 
@@ -48,7 +48,12 @@ module sf_thicken(points, thickness, direction = undef, slicing = "SLASH") {
                     dir_v
             ]
         ];
-        sf_solidify(points, surface_bottom, slicing);
+        if(swap_surface) {
+            sf_solidify(surface_bottom, points, slicing);
+        }
+        else {
+            sf_solidify(points, surface_bottom, slicing);
+        }
     }
 }