add VacuumPermittivity and fix adding user values to material editor in FEM

src/App/FreeCADInit.py

@@ -717,6 +717,7 @@ App.Units.Length        = App.Units.Unit(1)
 App.Units.Area          = App.Units.Unit(2)
 App.Units.Volume        = App.Units.Unit(3)
 App.Units.Mass          = App.Units.Unit(0,1) 
+# (length, weight, time, current, temperature, amount of substance, luminous intensity, angle)
 
 # Angle
 App.Units.Angle            = App.Units.Unit(0,0,0,0,0,0,0,1)
@@ -755,6 +756,7 @@ App.Units.ThermalTransferCoefficient   = App.Units.Unit(0,1,-3,0,-1)
 App.Units.HeatFlux                     = App.Units.Unit(0,1,-3,0,0)
 App.Units.DynamicViscosity             = App.Units.Unit(-1,1,-1)
 App.Units.KinematicViscosity           = App.Units.Unit(2,0,-1)
+App.Units.VacuumPermittivity           = App.Units.Unit(-3,-1,4,2)
 
 # clean up namespace
 del(InitApplications)

src/Base/Unit.cpp

@@ -452,6 +452,7 @@ QString Unit::getTypeString(void) const
     if(*this == Unit::HeatFlux                    )       return QString::fromLatin1("HeatFlux");
     if(*this == Unit::DynamicViscosity            )       return QString::fromLatin1("DynamicViscosity");
     if(*this == Unit::KinematicViscosity          )       return QString::fromLatin1("KinematicViscosity");
+    if(*this == Unit::VacuumPermittivity          )       return QString::fromLatin1("VacuumPermittivity");
 
     return QString();
 
@@ -499,3 +500,4 @@ Unit Unit::ThermalTransferCoefficient  (0,1,-3,0,-1);
 Unit Unit::HeatFlux                    (0,1,-3,0,0);
 Unit Unit::DynamicViscosity            (-1,1,-1);  // SI unit: kg/m/s
 Unit Unit::KinematicViscosity          (2,0,-1);  // SI unit: m^2/s, https://en.wikipedia.org/wiki/Viscosity#Kinematic_viscosity
+Unit Unit::VacuumPermittivity          (-3,-1,4,2); // SI unit: A²*s⁴/kg/m³ https://en.wikipedia.org/wiki/Permittivity#Vacuum_permittivity

src/Base/Unit.h

@@ -133,6 +133,7 @@ public:
     static Unit HeatFlux;
     static Unit DynamicViscosity;
     static Unit KinematicViscosity;
+    static Unit VacuumPermittivity;
 
     //@}
 protected:

src/Mod/Material/Templatematerial.yml

@@ -155,6 +155,11 @@
       Type: 'Quantity'
       URL: 'https://en.wikipedia.org/wiki/Volumetric_thermal_expansion_coefficient'
       Description: "Thermal expansion coefficient (linear) in [FreeCAD ThermalExpansionCoefficient unit]"
+- Electrical:
+    RelativePermittivity:
+      Type: 'Float'
+      URL: 'https://en.wikipedia.org/wiki/Relative_permittivity'
+      Description: "a material property, expressing the ratio to the permittivity of the Vaccum"
 - Architectural:
     Color:
       Type:  'String'
@@ -265,7 +270,7 @@
       Type: 'String'
       URL: ''
       Description: "Vendor of the material"
-- UserDefined:
+- User defined:
     None:  # Python needs something to iterate over
       Type: ''
       URL: ''

src/Mod/Material/importFCMat.py

@@ -156,6 +156,7 @@ def write(filename, dictionary, write_group_section=True):
 
     # sort the data into sections
     contents = []
+    user = {}
     template_data = get_material_template()
     for group in template_data:
         groupName = list(group.keys())[0]  # group dict has only one key
@@ -203,7 +204,8 @@ def write(filename, dictionary, write_group_section=True):
         FreeCAD.Console.PrintMessage("File CardName is used: {}\n".format(card_name_file))
     if sys.version_info.major >= 3:
         f.write("; " + card_name_file + "\n")
-        f.write("; " + header["AuthorAndLicense"] + "\n")
+        #f.write("; " + header["AuthorAndLicense"] + "\n")
+        f.write("; " + header.get("AuthorAndLicense", "no author") + "\n")
     else:
         f.write("; " + header["CardName"].encode("utf8") + "\n")
         f.write("; " + header["AuthorAndLicense"].encode("utf8") + "\n")