Add element geometry return option.

- provide test case to show how it can be used.

meshpy/geometry_set.py

@@ -246,6 +246,10 @@ def get_all_nodes(self):
                 "Currently GeometrySet are only implemented for points and lines"
             )
 
+    def get_geometry_objects(self):
+        """Return the objects of the specified geometry type."""
+        return self.geometry_objects[self.geometry_type]
+
 
 class GeometrySetNodes(GeometrySetBase):
     """Geometry set which is defined by nodes and not explicit geometry."""

tests/reference-files/test_get_geometry_set_to_boundary_conditions.dat

@@ -0,0 +1,39 @@
+// -----------------------------------------------------------------------------
+// This input file was created with MeshPy.
+// Copyright (c) 2018-2024
+//     Ivo Steinbrecher
+//     Institute for Mathematics and Computer-Based Simulation
+//     Universitaet der Bundeswehr Muenchen
+//     https://www.unibw.de/imcs-en
+// -----------------------------------------------------------------------------
+-----------------------------------------------------------------------MATERIALS
+MAT 1 MAT_BeamReissnerElastHyper YOUNG 1 POISSONRATIO 0.0 DENS 0.0 CROSSAREA 0.031415926535897934 SHEARCORR 1 MOMINPOL 0.00015707963267948968 MOMIN2 7.853981633974484e-05 MOMIN3 7.853981633974484e-05
+---------------------------------------------------DESIGN LINE DIRICH CONDITIONS
+DLINE 1
+E 1 - NUMDOF 9 ONOFF 1 1 1 0 0 0 0 0 0 VAL 0 0 0 0 0 0 0 0 0 FUNCT 0 0 0 0 0 0 0 0 0
+-------------------------------------------------------------DLINE-NODE TOPOLOGY
+NODE 3 DLINE 1
+NODE 4 DLINE 1
+NODE 5 DLINE 1
+NODE 6 DLINE 1
+NODE 7 DLINE 1
+NODE 8 DLINE 1
+NODE 9 DLINE 1
+---------------------------------------------------------------------NODE COORDS
+NODE 1 COORD 0 0 0
+NODE 2 COORD 0.2 0 0
+NODE 3 COORD 0.4 0 0
+NODE 4 COORD 0.6 0 0
+NODE 5 COORD 0.8 0 0
+NODE 6 COORD 1 0 0
+NODE 7 COORD 1.2 0 0
+NODE 8 COORD 1.4 0 0
+NODE 9 COORD 1.6 0 0
+NODE 10 COORD 1.8 0 0
+NODE 11 COORD 2 0 0
+--------------------------------------------------------------STRUCTURE ELEMENTS
+1 BEAM3R HERM2LINE3 1 3 2 MAT 1 TRIADS 0 0 0 0 0 0 0 0 0
+2 BEAM3R HERM2LINE3 3 5 4 MAT 1 TRIADS 0 0 0 0 0 0 0 0 0
+3 BEAM3R HERM2LINE3 5 7 6 MAT 1 TRIADS 0 0 0 0 0 0 0 0 0
+4 BEAM3R HERM2LINE3 7 9 8 MAT 1 TRIADS 0 0 0 0 0 0 0 0 0
+5 BEAM3R HERM2LINE3 9 11 10 MAT 1 TRIADS 0 0 0 0 0 0 0 0 0

tests/testing_meshpy.py

@@ -966,6 +966,43 @@ def get_arguments_curve(circle_type):
             additional_identifier=additional_identifier,
         )
 
+    def test_get_geometry_set_to_boundary_conditions(self):
+        """Test if the geometry set returns the objects(elements) and if they
+        can be forwarded to a GeometrySet."""
+
+        # Initialize material and input file.
+        mat = MaterialReissner(radius=0.1, youngs_modulus=1)
+        mesh = InputFile()
+
+        # number of elements
+        n_el = 5
+
+        # Create a simple beam.
+        geometry = create_beam_mesh_line(
+            mesh, Beam3rHerm2Line3, mat, [0, 0, 0], [2, 0, 0], n_el=n_el
+        )
+
+        # Check if all objects elements are returned.
+        elements_of_geometry = list(geometry["line"].get_geometry_objects().keys())
+
+        # First check type.
+        self.assertEqual(type(elements_of_geometry[0]), Beam3rHerm2Line3)
+
+        # Check number of elements.
+        self.assertEqual(len(elements_of_geometry), n_el)
+
+        # Add boundary condition to all elements except the first and last element.
+        mesh.add(
+            BoundaryCondition(
+                GeometrySet(elements_of_geometry[1:-1]),
+                "NUMDOF 9 ONOFF 1 1 1 0 0 0 0 0 0 VAL 0 0 0 0 0 0 0 0 0 FUNCT 0 0 0 0 0 0 0 0 0",
+                bc_type=mpy.bc.dirichlet,
+            )
+        )
+
+        # Compare with the reference file.
+        compare_test_result(self, mesh.get_string(header=False))
+
     def test_meshpy_replace_nodes_geometry_set(self):
         """Test case for coupling of nodes, and reusing the identical nodes.