From c83664b159a2c02c2a87b0004656e68b8228e56d Mon Sep 17 00:00:00 2001
From: wmayer <wmayer@users.sourceforge.net>
Date: Wed, 18 Oct 2017 10:40:02 +0200
Subject: [PATCH] increase minimum deviation for tessellation to avoid to
 freeze the GUI

---
 src/Mod/Part/Gui/DlgSettings3DViewPart.ui | 2 +-
 src/Mod/Part/Gui/ViewProviderExt.cpp      | 6 ++++--
 2 files changed, 5 insertions(+), 3 deletions(-)

diff --git a/src/Mod/Part/Gui/DlgSettings3DViewPart.ui b/src/Mod/Part/Gui/DlgSettings3DViewPart.ui
index 96b2580eb2..c2d238ba69 100644
--- a/src/Mod/Part/Gui/DlgSettings3DViewPart.ui
+++ b/src/Mod/Part/Gui/DlgSettings3DViewPart.ui
@@ -62,7 +62,7 @@
            <number>4</number>
           </property>
           <property name="minimum">
-           <double>0.000100000000000</double>
+           <double>0.0100000000000</double>
           </property>
           <property name="maximum">
            <double>100.000000000000000</double>
diff --git a/src/Mod/Part/Gui/ViewProviderExt.cpp b/src/Mod/Part/Gui/ViewProviderExt.cpp
index 158b1ef9f9..066b94d3b2 100644
--- a/src/Mod/Part/Gui/ViewProviderExt.cpp
+++ b/src/Mod/Part/Gui/ViewProviderExt.cpp
@@ -220,7 +220,7 @@ void ViewProviderPartExt::GetNormals(const TopoDS_Face&  theFace,
 // Construction/Destruction
 
 App::PropertyFloatConstraint::Constraints ViewProviderPartExt::sizeRange = {1.0,64.0,1.0};
-App::PropertyFloatConstraint::Constraints ViewProviderPartExt::tessRange = {0.0001,100.0,0.01};
+App::PropertyFloatConstraint::Constraints ViewProviderPartExt::tessRange = {0.01,100.0,0.01};
 App::PropertyQuantityConstraint::Constraints ViewProviderPartExt::angDeflectionRange = {1.0,180.0,0.05};
 const char* ViewProviderPartExt::LightingEnums[]= {"One side","Two side",NULL};
 const char* ViewProviderPartExt::DrawStyleEnums[]= {"Solid","Dashed","Dotted","Dashdot",NULL};
@@ -330,7 +330,9 @@ ViewProviderPartExt::~ViewProviderPartExt()
 
 void ViewProviderPartExt::onChanged(const App::Property* prop)
 {
-    
+    // The lower limit of the deviation has been increased to avoid
+    // to freeze the GUI
+    // https://forum.freecadweb.org/viewtopic.php?f=3&t=24912&p=195613
     Part::Feature* feature = dynamic_cast<Part::Feature*>(pcObject);
     if (prop == &Deviation) {
         if(Visibility.getValue() && feature && !feature->Shape.getValue().IsNull())