如何在 Python 中以编程方式更改 AutoCAD 对象的属性

Question

I want to automatically process a bunch of AutoCAD drawings using Python. To that end I need to change the properties of the drawing entities programmatically. I've been struggling for a while, to no avail.

This is the code I'm using to read the .dxf and open the .dwg files:

import win32com.client
import dxfgrabber
import os

folder = r'C:\path\to\my\folder'
filename = 'my_file'

dwg_path = os.path.join(folder, filename + '.dwg')
dxf_path = os.path.join(folder, filename + '.dxf')

acad = win32com.client.dynamic.Dispatch("AutoCAD.Application")
doc = acad.Documents.Open(dwg_path)
acad.Visible = True

dxf = dxfgrabber.readfile(dxf_path)

Then I iterate over the objects placed in a layer called FirstLayer and select one of them:

item = [obj for obj in dxf.entities if obj.layer == 'FirstLayer'][0]

This particular entity is a text object:

In [1122]: type(item)
Out[1122]: dxfgrabber.dxfentities.Text

In [1123]: item.insert
Out[1123]: (4022.763956904745, 3518.371877135191, 0.0)

In [1124]: item.layer
Out[1124]: 'FirstLayer'

In [1125]: item.handle
Out[1125]: '298'

My goal is to change properties such as color , layer , etc. This is one of my attempts to move the text object to a different layer called SecondLayer :

doc.SendCommand(f'CHPROP {item.insert[0]},{item.insert[1]} LA\n SecondLayer\n ')

I guess the problem is that the object cannot be selected through the coordinates of the insertion point. I also tried (unsuccessfully) to select the object by its handle using the following script:

_CHPROP (handent 298) _LA SecondLayer 

Any ideas on how to work around this?

---

EDIT
I came up with the following solution before @Lee Mac posted his excellent answer:

doc.SendCommand(f'CHPROP (handent "{item.handle}") \n_LA SecondLayer\n ')        

Answer 1

Upon issuing the CHPROP command, the subsequent object selection prompt will either require you to supply one or more entity names (which may be obtained by converting a handle using the AutoLISP handent function), or supplying a selection set (which may be obtained using the AutoLISP ssget function).

You were very close with your use of handent , however entity handles in AutoCAD are represented by hexadecimal strings and so you will need to supply the handent function with a string argument surrounded by double-quotes, eg:

(handent "298")

If the supplied handle is valid, handent will then return an entity name pointer:

_$ (handent "3B8")
<Entity name: 7ffff706880>

However, since CHPROP accepts a selection set argument, you needn't iterate over every entity, but instead simply supply CHPROP with a filter selection set, eg:

doc.SendCommand(f'CHPROP (ssget "_x" (list (cons 8 "FirstLayer"))) LA\n SecondLayer\n ')

Answer 2

The handle in DXF files is stored as HEX string, maybe AutoCAD requires an integer value, but I am not an AutoCAD expert (@LeeMac). Convert HEX string to int in Python by int('298', 16) .