From eb6a405c170dd7a7ef5035d5fd837099cdd14dc7 Mon Sep 17 00:00:00 2001
From: wmayer <wmayer@users.sourceforge.net>
Date: Thu, 17 Oct 2019 00:22:39 +0200
Subject: [PATCH] abort hyperbola creation when angles are NaN

---
 src/Mod/Sketcher/Gui/CommandCreateGeo.cpp | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/src/Mod/Sketcher/Gui/CommandCreateGeo.cpp b/src/Mod/Sketcher/Gui/CommandCreateGeo.cpp
index 40051ff20f..be0adda009 100644
--- a/src/Mod/Sketcher/Gui/CommandCreateGeo.cpp
+++ b/src/Mod/Sketcher/Gui/CommandCreateGeo.cpp
@@ -3770,6 +3770,12 @@ public:
             double endAngle = atanh( (((endPoint.y-centerPoint.y)*cos(phi)-(endPoint.x-centerPoint.x)*sin(phi))*a) /
                                          (((endPoint.x-centerPoint.x)*cos(phi)+(endPoint.y-centerPoint.y)*sin(phi))*b)  );
 
+            if (boost::math::isnan(startAngle) || boost::math::isnan(endAngle)) {
+                sketchgui->purgeHandler();
+                Base::Console().Error("Cannot create arc of hyperbola from invalid angles, try again!\n");
+                return false;
+            }
+
 
             bool isOriginalArcCCW=true;