pyzwcadmech 0.1.0

A Python wrapper for ZWCAD Mechanical COM API

pyzwcadmech Documentation

pyzwcadmech is a Python wrapper for the ZWCAD Mechanical COM API (ZwmToolKit.tlb). It encapsulates the underlying COM pointer operations into a Pythonic object-oriented API, allowing developers to easily read and modify mechanical-specific objects such as title blocks, BOMs (Bill of Materials), and drawing frames using Python scripts.

1. Requirements

• OS: Windows
• Software Dependency: A licensed installation of ZWCAD Mechanical.
• Python Environment: Python 3.x
• Third-party Libraries: comtypes (for COM component communication)

  pip install comtypes
  

• Core Files: The ZwmToolKit.tlb file will be automatically searched in the standard ZWCAD Mechanical installation path. If not found, ensure it is placed in the project root or the same directory as the pyzwcadmech module.

2. Directory Structure

Ensure your project directory has the following structure:

your_project_directory/
├── ZwmToolKit.tlb       # (Optional) COM type library file provided by ZWCAD Mechanical
├── pyzwcadmech/         # Core wrapper library
│   ├── __init__.py
│   └── api.py
└── hello_mech.py        # Your calling script

3. Quick Start

Below is a simple example demonstrating how to connect to ZWCAD Mechanical and read the title block data of the current drawing:

from pyzwcadmech import ZwCADMech

def main():
    # 1. Initialize and connect to ZWCAD Mechanical
    mech = ZwCADMech()
    
    # 2. Connect to the current active drawing
    mech.open_file("")
    
    # 3. Get and read the title block object
    title = mech.get_title()
    if title:
        print("Successfully obtained the title block object!")
        count = title.get_item_count()
        for i in range(count):
            label, name, value = title.get_item(i)
            print(f"{label}: {value}")
            
        # Modify title block properties
        # title.set_item("Designer", "John Doe")
        # mech.zwm_db.refresh_title() # Refresh the drawing display

    # 4. Interactive editing (pops up the ZWCAD Mechanical editing dialog)
    # mech.title_edit()
    
    # 5. Save and disconnect
    # mech.save()
    mech.close()

if __name__ == "__main__":
    main()

4. API Reference

4.1 Core Entry Class: ZwCADMech

ZwCADMech is the entry point of the entire library, responsible for managing the CAD process and the mechanical module database.

Initialization

mech = ZwCADMech(cad_app=None)

• cad_app: Optional. If you already have a ZWCAD.Application instance, you can pass it in. Otherwise, it will be automatically obtained or started.

Core Properties

• mech.app: Returns the native ZWCAD.Application COM object.
• mech.zwm_app: Returns the ZwmApp wrapper instance.
• mech.zwm_db: Returns the ZwmDb wrapper instance.

Shortcut Methods (Delegated to ZwmDb)

• open_file(filepath: str): Opens the specified DWG file. Passing an empty string "" means the current active document.
• save(flag: int = 33): Saves the current drawing.
• close(): Closes the database connection.
• get_title() -> ZwmTitle: Gets the title block object.
• get_bom() -> ZwmBom: Gets the BOM object.
• get_frame() -> ZwmFrame: Gets the drawing frame object.
• Interactive editing: title_edit(), total_bom_edit(), frame_edit(), fjl_edit()

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4.2 Title Block Object: ZwmTitle

• get_item_count() -> int: Gets the number of title block properties.
• get_item(index: int) -> tuple(str, str, str): Gets properties by index, returns (label, name, value).
• set_item(key: str, value: str): Sets the corresponding value by label or property name.

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4.3 BOM Object: ZwmBom & ZwmBomRow

ZwmBom (Entire BOM)

• get_item_count() -> int: Gets the number of rows in the BOM.
• get_item(index: int) -> ZwmBomRow: Gets the BOM row object at the specified index.
• set_item(index: int, bom_row: ZwmBomRow): Updates the data of the specified row.
• add_item(bom_row: ZwmBomRow): Adds a row to the end.
• insert_item(index: int, bom_row: ZwmBomRow): Inserts a row at the specified position.
• delete_item(index: int): Deletes the specified row.
• create_bom_row() -> ZwmBomRow: Creates a blank BOM row object for subsequent addition.

ZwmBomRow (Single BOM Row)

• get_item_count() -> int: Gets the number of columns (properties) in the row.
• get_item(index: int) -> tuple(str, str, str): Gets the data of the specified column, returns (label, name, value).
• set_item(key: str, value: str): Sets the value of the specified column.

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4.4 Drawing Frame Object: ZwmFrame

All properties of the drawing frame object are encapsulated as Python @property and can be read and written directly:

• Dimensions and Standards: width, height, std_name (e.g., "GB"), frame_size_name (e.g., "A3"), orientation, scale1, scale2.
• Style Names: frame_style_name, title_style_name, bom_style_name, dhl_style_name, fjl_style_name, csl_style_name, ggl_style_name.
• Included Elements (1=Yes, 0=No): have_dhl (Code Block), have_fjl (Additional Block), have_btl (Title Block), have_csl (Parameter Block), have_ggl (Modification Block).

After modifying properties, you must call mech.zwm_db.build_frame(511) or refresh_frame() to apply the changes to the drawing.

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4.5 Database Operations: ZwmDb

In addition to the basic methods delegated by ZwCADMech, ZwmDb also provides:

• switch_frame(frame_name: str): Switches the current operating drawing frame.
• get_frame_count() -> int: Gets the number of drawing frames in the drawing.
• get_frame_name(index: int) -> str: Gets the name of the drawing frame at the specified index.
• get_next_frm_name() -> tuple(ZwmFrame, str): Gets the object and name of the next newly created drawing frame.
• refresh_title(), refresh_bom(), refresh_frame(): Refreshes the display of the corresponding objects in the drawing.
• build_frame(switch_type: int = 511): Rebuilds the drawing frame block and associated blocks.

5. FAQ

Q: Running error Failed to load ZwmToolKit.tlb or ModuleNotFoundError A: Ensure that ZWCAD Mechanical is installed on your system. If it is installed in a non-standard path, please copy the ZwmToolKit.tlb file to the directory where the script is running, or place it next to the pyzwcadmech folder. Also, ensure the comtypes library is installed.

Q: Running error Failed to create ZwmToolKit.ZwmApp. Please check if ZWCAD Mechanical is installed and running. A: This is usually because:

1. The standard version of ZWCAD is installed on the computer, not the Mechanical version (ZWCAD Mechanical).
2. The COM component of ZWCAD Mechanical is not registered correctly. Try running ZWCAD Mechanical once as an administrator.

Q: Getting title block or BOM returns null or throws an error A: Ensure that mech.open_file("") has been successfully called to bind the drawing database before calling get_title() or get_bom(). Also, ensure that the title block or BOM entities of ZWCAD Mechanical actually exist in the current drawing.