Storing Custom Data in DXF Files

This tutorial describes how to store custom data in DXF files using standard DXF features.

Saving data in comments is not covered in this section, because comments are not a reliable way to store information in DXF files and ezdxf does not support adding comments to DXF files. Comments are also ignored by ezdxf and many other DXF libraries when loading DXF files, but there is a ezdxf.comments module to load comments from DXF files.

The DXF data format is a very versatile and flexible data format and supports various ways to store custom data. This starts by setting special header variables, storing XData, AppData and extension dictionaries in DXF entities and objects, storing XRecords in the OBJECTS section and ends by using proxy entities or even extending the DXF format by user defined entities and objects.

Retrieving User Data

Retrieving the is a simple task by ezdxf, but often not possible in CAD applications without using the scripting features (AutoLisp) or even the SDK.

Warning

Here you will not find any documentation about how to use the stored user data outside of ezdxf. I have no experience with AutoLisp and therefore there are no examples how to read and use the user data in AutoCAD or any other CAD application.

Header Section

Meta Data

XDATA

AppData

Extension Dictionaries

XRecord

UserRecord