How should I use the mapping workflow of DPF in Mechanical?

Pierre Thieffry

I want to map some data onto a mesh using DPF's mapping workflow. How can I do this?

Pierre Thieffry

Here's a sample code to use in a Python Code.

To insert commands just prior to the ANSYS SOLVE command, use solver_input_file.WriteLine("!Your command")
Global Helpers:
    this -- the datamodel object instance of the python code object you are currently editing in the tree
    solver_input_file  -- file stream that allows you to inject commands into the solver input file
    solver_data -- data stucture that allows you to access information from the model such as current step, contact pair ids, etc.
"""

# To access properties created using the Property Provider, please use the following command.
# this.GetCustomPropertyByPath("your_property_group_name/your_property_name")

# To access scoping properties use the following to access geometry scoping and named selection respectively:
# this.GetCustomPropertyByPath("your_property_group_name/your_property_name/Geometry Selection")
# this.GetCustomPropertyByPath("your_property_group_name/your_property_name/Named Selection")
import mech_dpf
import Ans.DataProcessing as dpf
import os

def GetDpfMeshFromMechMesh(ExtAPI, BodyIds=None):
    """
    Get a DPF mesh region from a mechanical mesh
    Args:
        BodyIds (list of int) (optional): Ids for GeoBodies to get region
    Returns:
        dpf.MeshedRegion
    """
    MechMesh=ExtAPI.DataModel.MeshDataByName("Global")
    #Get the node ids
    if BodyIds!=None:
        NdIds=set()
        for Id in BodyIds:
            Region=MechMesh.MeshRegionById(Id)
            NdIds.update(Region.NodeIds)
    else:
        NdIds=set(MechMesh.NodeIds)
    #convet to elem. ids.
    ElIds=MechMesh.ElementIdsFromNodeIds(NdIds)
    #Convert to Dpf MeshRegion
    DpfMesh=dpf.MeshedRegion(0,0)
    NdIndexByIds={}
    i=0
    for NdId in NdIds:
        N=MechMesh.NodeById(NdId)
        NdIndexByIds[N.Id]=i
        DpfMesh.AddNode(N.Id, [N.X, N.Y, N.Z])
        i+=1
    for ElId in ElIds:
        E=MechMesh.ElementById(ElId)
        DpfMesh.AddSolidElement(E.Id,[NdIndexByIds[N.Id] for N in E.Nodes])
    return DpfMesh

def readDataToMap(filename,scale_factor=1.):
    # Filename: file to read from. Assumes a tab separated file with
    # node_id X Y Z temperature and a first line to be ignored
    # Scale factor used to match mechanical mesh unit (m) and file contents unit
    with open(filename,'r') as f:
        lines=f.readlines()

    mapping_nodes=dpf.FieldsFactory.Create3DVectorField(len(lines)-1)
    mapping_field=dpf.FieldsFactory.CreateScalarField(len(lines)-1)

    idx=1
    for line in lines[1:]:
        line_sp=line.split('\t')
        coord=[float(line_sp[i])*scale_factor for i in range(1,4)]
        value=float(line_sp[4])
        mapping_nodes.Add(idx,coord)
        mapping_field.Add(idx,[value])
        idx+=1

    return mapping_nodes, mapping_field

# Convert Mechanical mesh to DPF mesh
mech_dpf.setExtAPI(ExtAPI)
dpf_mesh = GetDpfMeshFromMechMesh(ExtAPI)

# Get user_files folder
proj_dir=ExtAPI.DataModel.Project.ProjectDirectory
user_dir=os.path.join(proj_dir,'user_files')

# Read data to map
# Example file is in mm, so convert from mm to m
mapping_file=os.path.join(user_dir,'ExtData_Temp_Valve.txt')
source_nodes,source_field=readDataToMap(mapping_file,1e-3)

# Define mapping workflow
# This will prepare the mapping between the source points and the targets
filter_radius=10e-3

op = dpf.operators.mapping.prepare_mapping_workflow() # operator instantiation
op.inputs.input_support.Connect(source_nodes)
op.inputs.output_support.Connect(dpf_mesh)
op.inputs.filter_radius.Connect(filter_radius)
mapping_workflow = op.outputs.mapping_workflow.GetData()

# Now we can map the data
# THe workflow is reused multiple times for various
# source fields (here the variation is a scaling of the source field, so mapping is done only once)


mapping_workflow.Connect('source',source_field) #Connect field to be mapped

mapped_field=mapping_workflow.GetOutputAsField('target') # extract mapped value

field_data=mapped_field.Data
nids=mapped_field.ScopingIds

# Temperatures are scaled based on time step
for i in range(len(nids)):
    cmd='bf,{0},temp,{1}'.format(nids[i],field_data[i]*(1+(solver_data.CurrentStep-1)*.1))
    solver_input_file.WriteLine(cmd)