Of course! Here is a comprehensive guide to using Python with MicroStation, the popular CAD software from Bentley Systems.

This guide covers the fundamental concepts, necessary tools, code examples, and best practices for automating and extending MicroStation's functionality using Python.

What is MicroStation Python Automation?

Python automation in MicroStation involves using a Python script to control the MicroStation application, manipulate design files (DGN), create and modify geometry, manage elements, and interact with the user.

This is incredibly powerful for:

• Automating repetitive tasks: Batch processing files, changing element properties, numbering elements.
• Custom tool creation: Building complex tools that go beyond standard MicroStation capabilities.
• Data integration: Importing/exporting data from databases, Excel files, or web services directly into your design files.
• Custom reporting: Generating reports on elements, levels, or standards compliance.

The Two Main Approaches

There are two primary ways to use Python with MicroStation, each suited for different tasks.

Approach 1: The MicroStationPython Module (The "Classic" Way)

This is the original and most direct method. Bentley provides a Python module that acts as a wrapper for the MicroStation MicroStationAPI (C++ API). This gives you deep, low-level access to almost every part of MicroStation.

• How it works: You write a Python script that imports the MicroStationPython module. This module exposes objects like Application, DesignFile, Element, Level, etc.
• Pros:
  • Extremely powerful and comprehensive.
  • Direct access to the core MicroStation API.
  • Can handle almost any task imaginable within MicroStation.
• Cons:
  • Can be complex to learn, especially if you're not familiar with the MicroStation API.
  • The documentation is often tied to the C++ API documentation, which can be dense.
  • Primarily used for running scripts inside MicroStation.

Approach 2: The COM (Component Object Model) Interface (The "Modern" & Flexible Way)

This approach treats MicroStation as a COM Automation server. Your Python script runs outside of MicroStation and connects to a running instance of it. This is the same technology used by VBA (Visual Basic for Applications).

• How it works: You use a Python library like pywin32 on Windows to create a connection to MicroStation's COM objects. You then manipulate these objects from your script.
• Pros:
  • More flexible; the script can run independently.
  • Easier to integrate with other Windows applications (e.g., control Excel while also controlling MicroStation).
  • Can be easier to set up for simple tasks.
  • Good for interacting with the MicroStation UI.
• Cons:
  • Slower than the direct MicroStationPython module for heavy-duty geometry manipulation.
  • Less comprehensive access to the deepest parts of the API compared to the native module.
  • Windows-only.

Setting Up Your Environment

For Approach 1: MicroStationPython

This is the most common setup.

1. Install Python: Get a standard Python installation (e.g., from python.org) or use Anaconda. A 64-bit version is recommended.

   
   （图片来源网络，侵删）

2. Install MicroStation: Make sure you have a supported version of MicroStation (CONNECT Edition or V8i).

3. Locate the MicroStationPython.dll: This file is located in your MicroStation installation directory.

   • Example Path: C:\Program Files\Bentley\OpenRoads CONNECT Edition\Configuration\

4. Tell Python where to find it: You need to add the directory containing MicroStationPython.dll to your system's PATH environment variable, or you must run your script from that directory.

   Easiest Method (Recommended for beginners):

   • Copy your Python script (e.g., my_script.py) into the same folder as MicroStationPython.dll.
   • Open MicroStation.
   • Go to Utilities > Macro > Run.
   • Browse to and select your my_script.py file.
   • Click Run.

For Approach 2: COM with pywin32

1. Install Python: Get a standard Python installation for Windows.
2. Install pywin32: Open a command prompt or terminal and run:

   pip install pywin32

3. Start MicroStation: You must have at least one instance of MicroStation running for the script to connect to.

Code Examples

Let's look at how to perform common tasks in both approaches.

Example 1: Hello World & Get Active Design File

This is the "Hello, World!" of MicroStation automation. It connects to MicroStation and prints the full path of the currently open design file.

Using Approach 1: MicroStationPython

# This script must be run from within MicroStation (Utilities > Macro > Run)
import MicroStationPython
def main():
    # Get the application object from the module
    app = MicroStationPython.Application
    # Get the active design file
    dgnFile = app.ActiveDesignFile
    if dgnFile:
        # Print the full path of the design file
        print(f"Active DGN file path: {dgnFile.FullName}")
    else:
        print("No active design file.")
# The standard entry point for a MicroStation Python script
if __name__ == '__main__':
    main()

Using Approach 2: COM with pywin32

# This script runs from a standard Python terminal (like VS Code, PyCharm, or cmd)
# MicroStation must be running first.
import win32com.client
def main():
    try:
        # Connect to a running instance of MicroStation
        # The program ID "MicroStationDGN.Application" is key
        microstation = win32com.client.Dispatch("MicroStationDGN.Application")
        # Make events visible (optional, but useful for debugging)
        microstation.Visible = 1 
        # Get the active design file
        dgn_file = microstation.ActiveDesignFile
        if dgn_file:
            # The COM object properties are accessed like a dictionary
            print(f"Active DGN file path: {dgn_file.FullName}")
        else:
            print("No active design file.")
    except Exception as e:
        print(f"An error occurred: {e}")
        print("Please ensure MicroStation is running.")
if __name__ == '__main__':
    main()

Example 2: Create a Simple Line

Using Approach 1: MicroStationPython

import MicroStationPython
import sys
def main():
    app = MicroStationPython.Application
    dgnFile = app.ActiveDesignFile
    # Get the model (e.g., "Default")
    model = dgnFile.Models.GetModelByName("Default")
    if not model:
        print("Model 'Default' not found.")
        return
    # Start a command to create elements
    command = app.CommandHandler.StartCommand("PLACE LINE")
    # Define start and end points (as MicroStation DPoint3d)
    startPoint = MicroStationPython.DPoint3d(0, 0, 0)
    endPoint = MicroStationPython.DPoint3d(100, 100, 0)
    # Place the line by sending key-in strings
    # This is a common way to drive the UI
    app.CommandHandler.InputPoint(startPoint, 0)
    app.CommandHandler.InputPoint(endPoint, 1)
    # Terminate the command
    app.CommandHandler.StartCommand("CANCEL")
if __name__ == '__main__':
    main()

Using Approach 2: COM with pywin32

import win32com.client
import pythoncom # Needed for COM threading
def main():
    try:
        microstation = win32com.client.Dispatch("MicroStationDGN.Application")
        microstation.Visible = 1
        # Get the active model
        model = microstation.ActiveDesignFile.DefaultModel
        # Create a line element
        # The COM CreateLineElement2 method takes a complex type (LineElement)
        line = model.CreateLineElement2(None)
        # Set the start and end points
        line.StartPoint = (0, 0, 0)
        line.EndPoint = (100, 100, 0)
        # Add the element to the model
        model.AddElement(line)
        print("Line created successfully.")
    except Exception as e:
        print(f"An error occurred: {e}")
if __name__ == '__main__':
    main()

Learning Resources

• Bentley's Official Documentation (The Best Resource):

  • MicroStation API Documentation: The source of truth. Search for "MicroStation API Documentation" on the Bentley Communities site. It's written for C++ but the object hierarchies and methods are identical for Python.
  • MicroStation Python Examples: Bentley provides sample scripts. Look for them in your MicroStation installation directory, often under examples\Python.

• Community Resources:

  • Bentley Communities Forums: This is the place to ask questions. Search for existing threads on "Python" or "MicroStationPython".
  • The BE Communities Wiki: Often has user-contributed examples and tips.

• Python-Specific Resources:

  • MicroStation Python on GitHub: Search for repositories like bentley/microstation-python-samples or community-made projects. These are goldmines of practical code.
  • Standard Python Tutorials: For learning Python fundamentals (data types, loops, functions, etc.).

Summary: Which Approach Should You Use?

For anyone serious about MicroStation automation, learning Approach 1 (MicroStationPython) is highly recommended as it unlocks the software's full potential.