From 069768669562b0b033a603ed6eca282ab933d693 Mon Sep 17 00:00:00 2001
From: Russell Johnson <47639332+Russ4262@users.noreply.github.com>
Date: Sun, 2 Aug 2020 13:16:21 -0500
Subject: [PATCH] Path: PocketShape - Fixes ticket #4411

Existing code to determine if shape volume indeed existed, failed.
Added additional pre-check for existing edges in shape to determine if shape geometry indeed exists.
In forum:
[Ticket #4411 - Can only generate pocket once for this shape, then it fails.](https://forum.freecadweb.org/viewtopic.php?style=3&f=15&t=49035).
---
 src/Mod/Path/PathScripts/PathAreaOp.py | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/src/Mod/Path/PathScripts/PathAreaOp.py b/src/Mod/Path/PathScripts/PathAreaOp.py
index 067845c51d..0547f3ddcd 100644
--- a/src/Mod/Path/PathScripts/PathAreaOp.py
+++ b/src/Mod/Path/PathScripts/PathAreaOp.py
@@ -991,11 +991,13 @@ class ObjectOp(PathOp.ObjectOp):
         dwn = face.extrude(FreeCAD.Vector(0.0, 0.0, -5.0))
         upCmn = base.Shape.common(up)
         dwnCmn = base.Shape.common(dwn)
-        if upCmn.Volume == 0.0:
+        # Identify orientation based on volumes of common() results
+        if len(upCmn.Edges) > 0 and round(upCmn.Volume, 6) == 0.0:
             return True
-        elif dwnCmn.Volume == 0.0:
+        elif len(dwnCmn.Edges) > 0 and round(dwnCmn.Volume, 6) == 0.0:
             return False
-        if dwnCmn.Volume > upCmn.Volume:
+        if (len(upCmn.Edges) > 0 and len(dwnCmn.Edges) > 0 and
+                round(dwnCmn.Volume, 6) > round(upCmn.Volume, 6)):
             return True
         return False