From 7900a069c2822a141851e9416104d4961551f427 Mon Sep 17 00:00:00 2001
From: Aapo <aapo.lankinen@gmail.com>
Date: Wed, 24 Feb 2021 21:56:39 +0200
Subject: [PATCH] [TD] DrawViewPart.cpp: Fix a crash when user sets the
 PropertyVector Direction to zero.

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

diff --git a/src/Mod/TechDraw/App/DrawViewPart.cpp b/src/Mod/TechDraw/App/DrawViewPart.cpp
index 3c1aeea98c..658b194c04 100644
--- a/src/Mod/TechDraw/App/DrawViewPart.cpp
+++ b/src/Mod/TechDraw/App/DrawViewPart.cpp
@@ -335,6 +335,13 @@ short DrawViewPart::mustExecute() const
 
 void DrawViewPart::onChanged(const App::Property* prop)
 {
+    // If the user has set PropertyVector Direction to zero, set it along the default value instead (Front View).
+    // Otherwise bad things will happen because there'll be a normalization for direction calculations later.
+    Base::Vector3d dir = Direction.getValue();
+    if (DrawUtil::fpCompare(dir.Length(), 0.0)) {
+        Direction.setValue(Base::Vector3d(0.0, -1.0, 0.0));
+    }
+
     DrawView::onChanged(prop);
 
 //TODO: when scale changes, any Dimensions for this View sb recalculated.  DVD should pick this up subject to topological naming issues.