Fix combination of skin extraction with scoping

src/ansys/dpf/post/harmonic_mechanical_simulation.py

@@ -125,6 +125,8 @@ def _get_result_workflow(
             equivalent_op = self._model.operator(name="eqv_fc")
             wf.add_operator(operator=equivalent_op)
             # If a strain result, change the location now
+            # TBD: Why do we put the the equivalent operator
+            # before the averaging operator for strain results?
             if (
                 average_op is not None
                 and category == ResultCategory.equivalent

src/ansys/dpf/post/selection.py

@@ -33,6 +33,7 @@
 class _WfNames:
     data_sources = "data_sources"
     scoping = "scoping"
+    skin_input_mesh = "skin_input_mesh"
     final_scoping = "final_scoping"
     scoping_a = "scoping_a"
     scoping_b = "scoping_b"
@@ -404,9 +405,24 @@ def select_skin(
             be returned by the Operator ``operators.metadata.is_cyclic``. Used to get the skin
             on the expanded mesh.
         """
-        op = operators.mesh.skin(server=self._server)
-        self._selection.add_operator(op)
-        mesh_input = op.inputs.mesh
+
+        def connect_any(operator_input, input_value):
+            # Workaround to connect any inputs: see
+            # https://github.com/ansys/pydpf-core/issues/1670
+            operator_input._operator().connect(operator_input._pin, input_value)
+
+        skin_operator = operators.mesh.skin(server=self._server)
+        self._selection.add_operator(skin_operator)
+
+        initial_mesh_fwd_op = operators.utility.forward(server=self._server)
+        self._selection.set_input_name(
+            _WfNames.initial_mesh, initial_mesh_fwd_op.inputs.any
+        )
+        self._selection.add_operator(initial_mesh_fwd_op)
+
+        skin_operator_input_mesh_fwd_op = operators.utility.forward(server=self._server)
+        connect_any(skin_operator_input_mesh_fwd_op.inputs.any, initial_mesh_fwd_op)
+        self._selection.add_operator(skin_operator_input_mesh_fwd_op)
 
         if _is_model_cyclic(is_model_cyclic):
             mesh_provider_cyc = operators.mesh.mesh_provider()
@@ -436,13 +452,11 @@ def select_skin(
                     server=self._server,
                 )
                 self._selection.add_operator(mesh_by_scop_op)
-                op.inputs.mesh.connect(mesh_by_scop_op)
+                skin_operator_input_mesh_fwd_op.inputs.any(mesh_by_scop_op)
             else:
-                op.inputs.mesh.connect(mesh_provider_cyc)
-            self._selection.set_input_name(
-                _WfNames.initial_mesh, mesh_provider_cyc, 100
-            )  # hack
-            mesh_input = None
+                skin_operator_input_mesh_fwd_op.inputs.any(mesh_provider_cyc)
+
+            mesh_provider_cyc.connect(100, initial_mesh_fwd_op.outputs.any)
 
         elif elements is not None:
             if not isinstance(elements, Scoping):
@@ -453,34 +467,50 @@ def select_skin(
                 scoping=elements, server=self._server
             )
             self._selection.add_operator(mesh_by_scop_op)
-            mesh_input = mesh_by_scop_op.inputs.mesh
-            op.inputs.mesh.connect(mesh_by_scop_op)
+            skin_operator_input_mesh_fwd_op.inputs.any(mesh_by_scop_op.outputs.mesh)
+            connect_any(mesh_by_scop_op.inputs.mesh, initial_mesh_fwd_op.outputs.any)
 
-        if mesh_input is not None:
-            self._selection.set_input_name(_WfNames.initial_mesh, mesh_input)
+        if not _is_model_cyclic(is_model_cyclic):
             if location == result_native_location:
-                self._selection.set_output_name(_WfNames.mesh, op.outputs.mesh)
-        self._selection.set_output_name(_WfNames.skin, op.outputs.mesh)
+                self._selection.set_output_name(
+                    _WfNames.mesh, skin_operator.outputs.mesh
+                )
+
+        self._selection.set_output_name(_WfNames.skin, skin_operator.outputs.mesh)
         if location == locations.nodal and result_native_location == locations.nodal:
             self._selection.set_output_name(
-                _WfNames.scoping, op.outputs.nodes_mesh_scoping
+                _WfNames.scoping, skin_operator.outputs.nodes_mesh_scoping
             )
 
         elif not _is_model_cyclic(is_model_cyclic) and (
             result_native_location == locations.elemental
             or result_native_location == locations.elemental_nodal
         ):
             transpose_op = operators.scoping.transpose(
-                mesh_scoping=op.outputs.nodes_mesh_scoping, server=self._server
+                mesh_scoping=skin_operator.outputs.nodes_mesh_scoping,
+                server=self._server,
             )
             self._selection.add_operator(transpose_op)
-            self._selection.set_input_name(
-                _WfNames.initial_mesh, transpose_op.inputs.meshed_region
+            connect_any(
+                transpose_op.inputs.meshed_region, initial_mesh_fwd_op.outputs.any
             )
             self._selection.set_output_name(
                 _WfNames.scoping, transpose_op.outputs.mesh_scoping_as_scoping
             )
 
+        connect_any(
+            skin_operator.inputs.mesh, skin_operator_input_mesh_fwd_op.outputs.any
+        )
+
+        # Provide the input mesh from which a skin was generated
+        # This is useful because the skin_mesh contains the mapping of
+        # skin elements to the original mesh element indices, which is used
+        # by the solid_to_skin_fc operator. The skin_input_mesh can be passed
+        # to the solid_to_skin_fc operator to ensure that the mapping is correct.
+        self._selection.set_output_name(
+            _WfNames.skin_input_mesh, skin_operator_input_mesh_fwd_op.outputs.any
+        )
+
     def select_with_scoping(self, scoping: Scoping):
         """Directly sets the scoping as the spatial selection.
 

src/ansys/dpf/post/simulation.py

@@ -358,7 +358,7 @@ def split_mesh_by_properties(
             List[elemental_properties],
             Dict[elemental_properties, Union[int, List[int]]],
         ],
-    ) -> Meshes:
+    ) -> Union[Mesh, Meshes, None]:
         """Splits the simulation Mesh according to properties and returns it as Meshes.
 
         Parameters
@@ -1021,12 +1021,24 @@ def _create_averaging_operator(
                 )  # To keep for retro-compatibility
             else:
                 inpt = first_average_op.inputs.mesh
+
+            if self._model._server.meet_version("8.0"):
+                # solid mesh_input only supported for server version
+                # 8.0 and up
+                average_wf.set_input_name(
+                    _WfNames.skin_input_mesh, first_average_op.inputs.solid_mesh
+                )
             average_wf.set_input_name(_WfNames.skin, inpt)
             average_wf.connect_with(
                 selection.spatial_selection._selection,
                 output_input_names={_WfNames.skin: _WfNames.skin},
             )
 
+            average_wf.connect_with(
+                selection.spatial_selection._selection,
+                output_input_names={_WfNames.skin_input_mesh: _WfNames.skin_input_mesh},
+            )
+
         if location == locations.nodal:
             average_op = self._model.operator(name="to_nodal_fc")
         elif location == locations.elemental:
@@ -1035,6 +1047,6 @@ def _create_averaging_operator(
             average_op.connect(0, forward, 0)
         else:
             first_average_op = average_op
-
+        # Todo: returns None if location is ElementalNodal and skin is active
         if first_average_op is not None and average_op is not None:
             return (first_average_op, average_op)

tests/conftest.py

@@ -4,6 +4,7 @@
 pytest as a sesson fixture
 """
 import os
+import pathlib
 import re
 
 from ansys.dpf.core.check_version import get_server_version, meets_version
@@ -44,6 +45,12 @@ def get_lighting():
 running_docker = os.environ.get("DPF_DOCKER", False)
 
 
+def save_screenshot(dataframe, suffix=""):
+    """Save a screenshot of a dataframe plot, with the current test name."""
+    test_path = pathlib.Path(os.environ.get("PYTEST_CURRENT_TEST"))
+    dataframe.plot(screenshot=f"{'_'.join(test_path.name.split('::'))}_{suffix}.jpeg")
+
+
 def resolve_test_file(basename, additional_path=""):
     """Resolves a test file's full path based on the base name and the
     environment.