Part: set an absolute upper limit of the deflection for the shape tessellation to avoid useless results

src/Mod/Part/Gui/ViewProviderExt.cpp

@@ -940,8 +940,14 @@ void ViewProviderPartExt::updateVisual()
 
         // Since OCCT 7.6 a value of equal 0 is not allowed any more, this can happen if a single vertex
         // should be displayed.
-        if (deflection < gp::Resolution())
+        if (deflection < gp::Resolution()) {
             deflection = Precision::Confusion();
+        }
+
+        // For very big objects the computed deflection can become very high and thus leads to a useless
+        // tessellation. To avoid this the upper limit is set to 20.0
+        // See also forum: https://forum.freecad.org/viewtopic.php?t=77521
+        deflection = std::min(deflection, 20.0);
 
         // create or use the mesh on the data structure
         Standard_Real AngDeflectionRads = AngularDeflection.getValue() / 180.0 * M_PI;