Fem: Add displace mesh option to CalculiX

src/Mod/Fem/femobjects/solver_calculix.py

@@ -331,6 +331,16 @@ class SolverCalculiX(base_fempythonobject.BaseFemPythonObject):
                 value=False,
             )
         )
+        prop.append(
+            _PropHelper(
+                type="App::PropertyBool",
+                name="DisplaceMesh",
+                group="Solver",
+                doc="Deform the mesh by the displacement field",
+                value=False,
+            )
+        )
+
         return prop
 
     def onDocumentRestored(self, obj):

src/Mod/Fem/femsolver/calculix/calculixtools.py

@@ -31,6 +31,8 @@ import tempfile
 import os
 import shutil
 
+from vtk.util import numpy_support as vtk_np
+
 import FreeCAD
 import Fem
 
@@ -174,6 +176,8 @@ class CalculiXTools(ObjectTools):
                 vtm_file = os.path.join(self.obj.WorkingDirectory, f)
                 pipeline.read(vtm_file)
                 pipeline.renameArrays(self.frd_var_conversion(self.obj.AnalysisType))
+                if self.obj.DisplaceMesh:
+                    self._generate_disp_mesh(pipeline)
                 break
 
         if create:
@@ -218,6 +222,24 @@ class CalculiXTools(ObjectTools):
             case _:
                 return "None"
 
+    def _generate_disp_mesh(self, pipeline):
+        try:
+            mb = pipeline.Data
+            for i in range(mb.GetNumberOfBlocks()):
+                grid = mb.GetBlock(i)
+                if not grid.GetPointData().HasArray("Displacement"):
+                    return
+                points = grid.GetPoints()
+                pd = points.GetData()
+                disp = grid.GetPointData().GetAbstractArray("Displacement")
+                disp_points = vtk_np.vtk_to_numpy(pd) + vtk_np.vtk_to_numpy(disp)
+                disp_points = vtk_np.numpy_to_vtk(disp_points)
+                points.SetData(disp_points)
+
+            pipeline.Data = mb
+        except Exception as e:
+            pass
+
     def version(self):
         p = QProcess()
         ccx_bin = settings.get_binary("Calculix")