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Objective:

Learn how to execute an nTop notebook using nTop Automate (ntopcl) within Python scripts to enable automated, repeatable workflows.

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Applies to:

  • Automating nTop notebooks for engineering workflows
  • Interacting with external software suites and databases

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Procedure:

  • Prepare the nTop notebook and JSON input for running nTop Automate
  • Use Python’s json module to save your input data (formatted as a dictionary) into a .json file.
  • Execute the nTop Automate process using Python’s subprocess module
  • Python Script_JSON.py will run a Windows process command like
"C:/Program Files/nTopology/nTopology/nTopCL.exe" -j input.json -o out.json SampleFile.ntop
  • Check if the return messages are printed as below.
[info] Logging Engine started
[info] Login successful[info] Parasolid started
[info] Parasolid started
[info] nTop successfully built.
[info] Logout successful
Feel free to change this script to batch process your workflow by passing input lists in a For Loop! 
#Imports
import os
import subprocess
import json

#Assuming this script, ntop file, and json files will be in the same folder
Current_Directory = os.path.dirname(os.path.realpath('__file__'))
exePath = r"C:/Program Files/nTopology/nTopology/nTopCL.exe" #nTopCL path
nTopFilePath = r"SampleFile.ntop" #nTop notebook file name
Input_File_Name = "input.json" #JSON input file name to be saved as
Output_File_Name = "out.json" #JSON output file name to be saved as

#Input variables in JSON structure
Inputs_JSON = {
 "inputs": [
 {
 	"name": "Output directory",
 	"type": "text",
 	"value": "C:\\Users\\Your Account\\Your Path\\"
 	},
 	{
 "name": "Length",
 "type": "scalar",
 "values": 7,
 "units": "mm"
 },
 	{
 "name": "Width",
 "type": "scalar",
 "values": 2,
 "units": "mm"
 },
 	{
 "name": "Height",
 "type": "scalar",
 "values": 2,
 "units": "mm"
 }
 ]
}

#nTopCL arguments in a list
Arguments = [exePath] #nTopCL path
Arguments.append("-j") #json input argument
Arguments.append(Input_File_Name) #json path
Arguments.append("-o") #output argument
Arguments.append(Output_File_Name) #output json path
Arguments.append(nTopFilePath) #.ntop notebook file path

#Creating in.json file
with open(Input_File_Name, 'w') as outfile:
 json.dump(Inputs_JSON, outfile, indent=4)

#nTopCL call with arguments
print(" ".join(Arguments))
output,error = subprocess.Popen(Arguments,stdout = subprocess.PIPE,
 stderr= subprocess.PIPE).communicate()

#Print the return messages
print(output.decode("utf-8"))
And that’s it! You’ve successfully run your nTop notebook using a Python script. Are you still having issues? Contact the support team, and we’ll be happy to help!

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Download the Example file:

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Keywords:

ntopcl command line python api script run scripts code cl