General Document

General preconditions:

import sys
import ezdxf

try:
    doc = ezdxf.readfile("your_dxf_file.dxf")
except IOError:
    print(f'Not a DXF file or a generic I/O error.')
    sys.exit(1)
except ezdxf.DXFStructureError:
    print(f'Invalid or corrupted DXF file.')
    sys.exit(2)
msp = doc.modelspace()

This works well with DXF files from trusted sources like AutoCAD or BricsCAD, for loading DXF files with minor or major flaws look at the ezdxf.recover module.

Load DXF Files with Structure Errors

If you know the files you will process have most likely minor or major flaws, use the ezdxf.recover module:

import sys
from ezdxf import recover

try:  # low level structure repair:
    doc, auditor = recover.readfile(name)
except IOError:
    print(f'Not a DXF file or a generic I/O error.')
    sys.exit(1)
except ezdxf.DXFStructureError:
    print(f'Invalid or corrupted DXF file: {name}.')
    sys.exit(2)

# DXF file can still have unrecoverable errors, but this is maybe
# just a problem when saving the recovered DXF file.
if auditor.has_errors:
    print(f'Found unrecoverable errors in DXF file: {name}.')
    auditor.print_error_report()

For more loading scenarios follow the link: ezdxf.recover

Set/Get Header Variables

ezdxf has an interface to get and set HEADER variables:

doc.header['VarName'] = value
value = doc.header['VarName']

See also

HeaderSection and online documentation from Autodesk for available header variables.

Set DXF Drawing Units

The header variable $INSUNITS defines the drawing units for the modelspace and therefore for the DXF document if no further settings are applied. The most common units are 6 for meters and 1 for inches.

Use this HEADER variables to setup the default units for CAD applications opening the DXF file. This setting is not relevant for ezdxf API calls, which are unitless for length values and coordinates and decimal degrees for angles (in most cases).

Sets drawing units:

doc.header['$INSUNITS'] = 6

For more information see section DXF Units.

Create More Readable DXF Files (DXF Pretty Printer)

DXF files are plain text files, you can open this files with every text editor which handles bigger files. But it is not really easy to get quick the information you want.

Create a more readable HTML file (DXF Pretty Printer):

# on Windows
py -3 -m ezdxf.pp your_dxf_file.dxf

# on Linux/Mac
python3 -m ezdxf.pp your_dxf_file.dxf

This produces a HTML file your_dxf_file.html with a nicer layout than a plain DXF file and DXF handles as links between DXF entities, this simplifies the navigation between the DXF entities.

Changed in version 0.8.3: Since ezdxf v0.8.3, a script called dxfpp will be added to your Python script path:

usage: dxfpp [-h] [-o] [-r] [-x] [-l] FILE [FILE ...]

positional arguments:
  FILE             DXF files pretty print

optional arguments:
  -h, --help       show this help message and exit
  -o, --open       open generated HTML file with the default web browser
  -r, --raw        raw mode - just print tags, no DXF structure interpretation
  -x, --nocompile  don't compile points coordinates into single tags (only in
                   raw mode)
  -l, --legacy     legacy mode - reorders DXF point coordinates

Important

This does not render the graphical content of the DXF file to a HTML canvas element.

Calculate Extents for the Modelspace

Since ezdxf v0.16 exist a ezdxf.bbox module to calculate bounding boxes for DXF entities. This module makes the extents calculation very easy, but read the documentation for the bbox module to understand its limitations.

import ezdxf
from ezdxf import bbox

doc = ezdxf.readfile("your.dxf")
msp = doc.modelspace()

extents = bbox.extents(msp)

The returned extents is a ezdxf.math.BoundingBox object.

Set Initial View/Zoom for the Modelspace

To show an arbitrary location of the modelspace centered in the CAD application window, set the '*Active' VPORT to this location. The DXF attribute dxf.center defines the location in the modelspace, and the dxf.height specifies the area of the modelspace to view. Shortcut function:

doc.set_modelspace_vport(height=10, center=(10, 10))

New in version 0.16.

The new ezdxf.zoom module of ezdxf v0.16, makes this task much easier.

Setting the initial view to the extents of all entities in the modelspace:

import ezdxf
from ezdxf import zoom

doc = ezdxf.readfile("your.dxf")
msp = doc.modelspace()
zoom.extents(msp)

Setting the initial view to the extents of just some entities:

lines = msp.query("LINES")
zoom.objects(lines)

The zoom module also works for paperspace layouts.

Important

The zoom module uses the bbox module to calculate the bounding boxes for DXF entities. Read the documentation for the bbox module to understand its limitations and the bounding box calculation for large documents can take a while!