FEM: mesh api, import of z88 mesh file with Fem API

src/Mod/Fem/App/FemMesh.cpp

@@ -1169,6 +1169,41 @@ void FemMesh::readNastran(const std::string &Filename)
 
 }
 
+void FemMesh::readZ88(const std::string &FileName)
+{
+    Base::TimeInfo Start;
+    Base::Console().Log("Start: FemMesh::readZ88() =================================\n");
+
+    /*
+    Python command to read Z88 mesh file from test suite:
+    from feminout.importZ88Mesh import read as read_z88
+    femmesh = read_z88(FreeCAD.ConfigGet("AppHomePath") + 'Mod/Fem/femtest/testfiles/mesh/tetra10_mesh.z88')
+    */
+
+    PyObject* module = PyImport_ImportModule("feminout.importZ88Mesh");
+    if (!module)
+        return;
+    try {
+        Py::Module z88mod(module, true);
+        Py::Callable method(z88mod.getAttr("read"));
+        Py::Tuple args(1);
+        args.setItem(0, Py::String(FileName));
+        Py::Object mesh(method.apply(args));
+        if (PyObject_TypeCheck(mesh.ptr(), &FemMeshPy::Type)) {
+            FemMeshPy* fempy = static_cast<FemMeshPy*>(mesh.ptr());
+            FemMesh* fem = fempy->getFemMeshPtr();
+            *this = *fem; // the deep copy should be avoided, a pointer swap method could be implemented
+                          // see https://forum.freecadweb.org/viewtopic.php?f=10&t=31999&start=10#p274241
+        }
+        else {
+            throw Base::FileException("Problems reading file");
+        }
+    }
+    catch (Py::Exception& e) {
+        e.clear();
+    }
+    Base::Console().Log("    %f: Done \n",Base::TimeInfo::diffTimeF(Start,Base::TimeInfo()));
+}
 
 void FemMesh::read(const char *FileName)
 {
@@ -1207,6 +1242,10 @@ void FemMesh::read(const char *FileName)
         FemVTKTools::readVTKMesh(File.filePath().c_str(), this);
     }
 #endif
+    else if (File.hasExtension("z88") ) {
+        // read Z88 mesh file
+        readZ88(File.filePath());
+    }
     else{
         throw Base::FileException("Unknown extension");
     }

src/Mod/Fem/App/FemMesh.h

@@ -157,6 +157,7 @@ public:
 private:
     void copyMeshData(const FemMesh&);
     void readNastran(const std::string &Filename);
+    void readZ88(const std::string &Filename);
 
 private:
     /// positioning matrix

src/Mod/Fem/App/FemMeshPy.xml

@@ -61,14 +61,16 @@
         </Methode>
         <Methode Name="read">
             <Documentation>
-                <UserDocu>Read in a DAT, UNV, MED or STL file.</UserDocu>
+                <UserDocu>Read in a various FEM mesh file formats.
+                    read(file.endingToExportTo)
+                    supported formats: DAT, MED, STL, UNV, VTK, Z88</UserDocu>
             </Documentation>
         </Methode>
         <Methode Name="write" Const="true">
             <Documentation>
                 <UserDocu>Write out various FEM mesh file formats.
                     write(file.endingToExportTo)
-                    supported formats: DAT, INP, MED, STL, UNV, VTK, Z88
+                    supported formats: BDF, DAT, INP, MED, STL, UNV, VTK, Z88
                 </UserDocu>
             </Documentation>
         </Methode>

src/Mod/Fem/Init.py

@@ -31,7 +31,7 @@ import FreeCAD
 FreeCAD.addExportType("FEM mesh TetGen (*.poly)", "feminout.convert2TetGen")
 
 # see FemMesh::read() and FemMesh::write() methods in src/Mod/Fem/App/FemMesh.cpp
-FreeCAD.addImportType("FEM mesh formats (*.unv *.med *.dat *.bdf *.vtk *.vtu)", "Fem")
+FreeCAD.addImportType("FEM mesh formats (*.unv *.med *.dat *.bdf *.vtk *.vtu *.z88)", "Fem")
 FreeCAD.addExportType("FEM mesh formats (*.unv *.med *.stl *.dat *.inp *.vtk *.vtu *.z88)", "Fem")
 
 FreeCAD.addImportType("FEM mesh CalculiX/Abaqus (*.inp)", "feminout.importInpMesh")
@@ -40,7 +40,7 @@ FreeCAD.addImportType("FEM result CalculiX (*.frd)", "feminout.importCcxFrdResul
 FreeCAD.addImportType("FEM mesh Fenics (*.xml *.xdmf)", "feminout.importFenicsMesh")
 FreeCAD.addExportType("FEM mesh Fenics (*.xml *.xdmf)", "feminout.importFenicsMesh")
 
-FreeCAD.addImportType("FEM mesh Z88 (*i1.txt *.z88)", "feminout.importZ88Mesh")
+FreeCAD.addImportType("FEM mesh Z88 (*i1.txt)", "feminout.importZ88Mesh")
 FreeCAD.addExportType("FEM mesh Z88 (*i1.txt)", "feminout.importZ88Mesh")
 
 FreeCAD.addImportType("FEM result Z88 displacements (*o2.txt)", "feminout.importZ88O2Results")

src/Mod/Fem/femtest/testmesh.py

@@ -357,9 +357,8 @@ class TestMeshEleTetra10(unittest.TestCase):
         # fcc_print(outfile)
         # fcc_print(testfile)
         self.femmesh.write(outfile)  # write the mesh
-        from feminout.importZ88Mesh import read as read_z88
-        femmesh_testfile = read_z88(outfile)  # read the mesh from written mesh
-        femmesh_outfile = read_z88(testfile)  # read the mesh from test mesh
+        femmesh_testfile = Fem.read(outfile)  # read the mesh from written mesh
+        femmesh_outfile = Fem.read(testfile)  # read the mesh from test mesh
         # reading the test mesh
         self.assertEqual(
             femmesh_testfile.Nodes,