How do I calculate element face normal of a solid element?

Ayush Kumar
Ayush Kumar Member, Moderator, Employee Posts: 389
First Anniversary Ansys Employee Solution Developer Community of Practice Member First Answer
edited June 2023 in Structures

How do I calculate element face (skin - outer element) normal of a solid element?

Tagged:

Answers

  • Ayush Kumar
    Ayush Kumar Member, Moderator, Employee Posts: 389
    First Anniversary Ansys Employee Solution Developer Community of Practice Member First Answer
    Answer ✓

    For 22R2 and above:

    import mech_dpf 
    import Ans.DataProcessing as dpf
    
    analysis = Model.Analyses[0]
    model = dpf.DataSources(analysis.ResultFileName)
    
    # Element ID for which you want a element face normal
    element_id = 1596
    
    # Get Mesh
    op = dpf.operators.mesh.mesh_provider() # operator instanciation
    op.inputs.data_sources.Connect(model)
    my_mesh = op.outputs.mesh.GetData()
    
    nodal_scoping = dpf.Scoping(Location="Nodal")
    nodal_scoping.Ids = my_mesh.ElementById(element_id).NodeIds
    
    # Extract Skin mesh from solid mesh
    skin_mesh = dpf.operators.mesh.skin(mesh=my_mesh)
    skin_mesh.inputs.mesh_scoping.Connect(nodal_scoping)
    skin_meshed_region = skin_mesh.outputs.mesh.GetData()
    
    # Get corresponding skin mesh element(s)
    element_scoping = dpf.Scoping(Location="Elemental")
    solid_element_index = my_mesh.ElementIds.IndexOf(element_id)
    
    # Calculate normal to the element face
    normal = dpf.operators.geo.normals_provider_nl()
    normal.inputs.mesh.Connect(skin_meshed_region)
    normal_vec_out_field = normal.outputs.field.GetData()
    
    # Get all normal vectors to the element face(s)
    skin_element_ids = skin_meshed_region.ElementScoping.Ids
    normal_vectors = [normal_vec_out_field.GetEntityDataById(skin_element) for skin_element in skin_element_ids]
    

    for 2021R2:

    import mech_dpf 
    import Ans.DataProcessing as dpf
    
    analysis = Model.Analyses[0]
    model = dpf.DataSources(analysis.ResultFileName)
    
    # Element ID for which you want a element face normal
    element_id = 1596
    
    # Get Mesh
    op = dpf.operators.mesh.mesh_provider() # operator instanciation
    op.inputs.data_sources.Connect(model)
    my_mesh = op.outputs.mesh.GetData()
    
    # Extract Skin mesh from solid mesh
    skin_mesh = dpf.operators.mesh.skin(mesh=my_mesh)
    skin_meshed_region = skin_mesh.outputs.mesh.GetData()
    
    """
    Skin mesh to solid mesh mapper.
    This is needed becauses DPF creates new element IDs for skin mesh.
    
    The location of solid element and corresponding skin mesh element is same,
    therefore a mapper based on the location.
    """
    skin_mesh_mapper = skin_mesh.outputs.property_field_new_elements_to_old.GetData()
    
    # Get corresponding skin mesh element(s)
    element_scoping = dpf.Scoping(Location="Elemental")
    solid_element_index = my_mesh.ElementIds.IndexOf(element_id)
    
    indexes = []
    for index in range(len(skin_mesh_mapper.Data)):
        if skin_mesh_mapper.Data[index] == solid_element_index:
            indexes.append(index)
    
    element_scoping.Ids = [skin_mesh_mapper.Scoping.Ids[index] for index in indexes]
    
    # Calculate normal to the element face
    normal = dpf.operators.geo.normals_provider_nl()
    normal.inputs.mesh.Connect(skin_meshed_region)
    normal.inputs.mesh_scoping.Connect(element_scoping)
    normal_vec_out_field = normal.outputs.field.GetData()
    
    # Get all normal vectors to the element face(s)
    normal_vectors = [normal_vec_out_field.GetEntityDataById(skin_element) for skin_element in element_scoping.Ids]