Connecting nodes and nodal values from external files

[SIM905]

I would like to show results from external file to Ansys Mechanical mesh using PyMAPDL.

I have a .cdb file with mesh from Mechanical and I have .csv with custom results from external software where each column has its own result with the first column having the node ID number.

I am struggling with assigning the values to each node and show the results on mesh in PyMAPDL.

from ansys.mapdl.core import launch_mapdl
import os
import sys
import pandas as pd

os.chdir(os.path.dirname(sys.argv[0]))

mapdl = launch_mapdl()
mapdl.clear()
mapdl.prep7()

mapdl.csys(0)

mapdl.cdread("db", "mesh_body.cdb")
node_ids = mapdl.mesh.nnum

print("Node IDs:", max(node_ids))

csv_file = "results.csv"
df = pd.read_csv(csv_file)

custom_result_dict = df.set_index("Node ID")["Custom result (unit)"].to_dict()
print("Node data from csv:")
for node_id in node_ids:
    custom_result = custom_result_dict.get(node_id, 0.0)
    print(f"Node ID: {node_id}, Result: {custom_result} unit")

mapdl.eplot()
mapdl.save()
mapdl.finish()

[mikerife]

Hi @SIM905
Before I answer can I ask if you really want to do this...or is it just a solution that you thought up. The reason I am asking is that:

1. If you are using WB Mechanical you could do this with a Python Result in WB Mechanical and have a native WB Mech result plot.

2. If you want/need to work outside of WB Mechanical, then do you want a MAPDL style plot or a native PyMAPDL style plot (PyVista based)?

3. If you want a native PyMAPDL style plot, PyVista, then you don't need to read the csv data into the MAPDL instance as some result to plot.

I can create a simple example once I know exactly what you are looking for. Mike

[SIM905]

Hi @mikerife

thank you for your kind reply.

I just managed to make the script taht work with PyMAPDL, since this was my initial goal. However, I will be glad if you can assit me also in making the Python Result inside WB (plotting external results from .csv to my mesh). This workflow will be often used when I receive results from external software.

Here is the current code:

`
import numpy as np
import pandas as pd
import pyvista as pv

from ansys.mapdl.core import launch_mapdl

mapdl = launch_mapdl()
print(mapdl)

mapdl.clear()
mapdl.prep7()

mesh_file = "mesh_body.cdb"
mapdl.cdread("db", mesh_file)

grid = mapdl.mesh.grid # save mesh as a VTK object

csv_file = "results.csv"
df = pd.read_csv(csv_file)

node_ids = mapdl.mesh.nnum
if not set(df["Node ID"].tolist()) <= set(node_ids):
print("Warning: Some node IDs in the CSV may not exist in the mesh.")

node_values = dict(zip(df["Node ID"], df["Custom result"]))

solution_values = [node_values.get(node_id, 0) for node_id in node_ids]
solution_array = np.array(solution_values)

wrapped = pv.PolyData(mapdl.mesh.nodes)
wrapped["Custom result"] = solution_array # Add the scalar 'Custom result' to PolyData

inter_grid = grid.interpolate(
wrapped,
sharpness=5,
radius=0.0001,
strategy="closest_point",
progress_bar=True,
)

inter_grid.plot(show_edges=False)
mapdl.exit()
`

[mikerife]

@SIM905
Check this Ansys Developer Forum post. The forum is open to all...well there are internal Ansys employee discussion groups but the idea is a place to discuss scripting. Mike