From eafba8cbfe0ecca748bf7e1157a57f01f226fabc Mon Sep 17 00:00:00 2001
From: WandererFan <wandererfan@gmail.com>
Date: Mon, 22 Jan 2018 16:11:33 -0500
Subject: [PATCH] Fix Exception when Source Shape IsNull

---
 src/Mod/TechDraw/App/DrawViewPart.cpp | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/src/Mod/TechDraw/App/DrawViewPart.cpp b/src/Mod/TechDraw/App/DrawViewPart.cpp
index 8fa99a850a..7c43e2c6cd 100644
--- a/src/Mod/TechDraw/App/DrawViewPart.cpp
+++ b/src/Mod/TechDraw/App/DrawViewPart.cpp
@@ -195,15 +195,20 @@ TopoDS_Shape DrawViewPart::getSourceShape(void) const
         BRep_Builder builder;
         TopoDS_Compound comp;
         builder.MakeCompound(comp);
+        bool found = false;
         for (auto& s:sourceShapes) {
             if (s.IsNull()) {
                 continue;    //has no shape
             }
+            found = true;
             BRepBuilderAPI_Copy BuilderCopy(s);
             TopoDS_Shape shape = BuilderCopy.Shape();
             builder.Add(comp, shape);
-        }        
-        result = comp;
+        }
+        //it appears that an empty compound is !IsNull(), so we need to check if we added anything to the compound.
+        if (found) {
+            result = comp;
+        }
     }
     return result;
 }