From 69d9a3f949c0669ef4c780c5df68e057cecfb809 Mon Sep 17 00:00:00 2001
From: Yorik van Havre <yorik@uncreated.net>
Date: Fri, 24 Aug 2018 23:10:10 -0300
Subject: [PATCH] Arch: Use the smallest face as profile when discovering
 extrusions in IFC objects - thanks @geometrygym

---
 src/Mod/Arch/ArchCommands.py | 13 +++++++------
 1 file changed, 7 insertions(+), 6 deletions(-)

diff --git a/src/Mod/Arch/ArchCommands.py b/src/Mod/Arch/ArchCommands.py
index e2a39d4c65..9072a98bc7 100644
--- a/src/Mod/Arch/ArchCommands.py
+++ b/src/Mod/Arch/ArchCommands.py
@@ -1253,13 +1253,14 @@ def getExtrusionData(shape):
                 if round(f[1].getAngle(faces[pair[0]][1]),4) != 1.5708:
                     ok = False
         if ok:
-            valids.append([faces[pair[0]][0],faces[pair[1]][0].CenterOfMass.sub(faces[pair[0]][0].CenterOfMass)])
-    for v in valids:
-        # prefer vertical extrusions
-        if v[1].getAngle(FreeCAD.Vector(0,0,1)) < 0.0001:
-            return v
-    # otherwise return the first found
+            # prefer the face with the lowest z
+            if faces[pair[0]][0].CenterOfMass.z < faces[pair[1]][0].CenterOfMass.z:
+                valids.append([faces[pair[0]][0],faces[pair[1]][0].CenterOfMass.sub(faces[pair[0]][0].CenterOfMass)])
+            else:
+                valids.append([faces[pair[1]][0],faces[pair[0]][0].CenterOfMass.sub(faces[pair[1]][0].CenterOfMass)])
     if valids:
+        # sort by smallest area
+        valids.sort(key=lambda v: v[0].Area)
         return valids[0]
     return None