Guide

DXF and DWG CAD Formats: The Complete Technical Guide

PC By Pablo Cirre • Updated May 7, 2026

What Are DXF and DWG?

DWG (Drawing) is the native binary format of AutoCAD, the world's leading CAD (Computer-Aided Design) software by Autodesk. Created in 1982 when AutoCAD launched, DWG has become the de facto standard for technical drawings in architecture, engineering, and construction (AEC) globally.

DXF (Drawing Exchange Format) is a documented interchange format also created by Autodesk in 1982 as an open alternative to DWG — designed to allow other CAD systems to import and export AutoCAD drawings. DXF is text-based (ASCII) by default, though binary DXF also exists. Because its specification is publicly documented, DXF is supported by virtually every CAD application on earth.

Both formats store 2D and 3D vector geometry: lines, arcs, circles, polylines, splines, surfaces, solids, blocks, text, dimensions, layers, hatches, and raster image references.

DWG Format History and Versions

DWG is proprietary — Autodesk does not publish its specification. This has led to a long-running legal battle and the creation of the Open Design Alliance (ODA/Teigha), which reverse-engineered DWG. Major DWG versions correspond to AutoCAD releases:

DWG Version	AutoCAD Release	Year
R13	AutoCAD R13	1994
R14	AutoCAD R14	1997
2000 (AC1015)	AutoCAD 2000-2002	1999
2004 (AC1018)	AutoCAD 2004-2006	2003
2007 (AC1021)	AutoCAD 2007-2009	2006
2010 (AC1024)	AutoCAD 2010-2012	2009
2013 (AC1027)	AutoCAD 2013-2017	2012
2018 (AC1032)	AutoCAD 2018-2024	2017

The first six bytes of a DWG file contain the version string: AC1032 for DWG 2018 format. AutoCAD can save to older versions ("Save As" with older format selection) for interoperability.

DXF Structure

DXF files are organized in sections, each consisting of group codes (integers) and associated values:

0            ← group code (entity type)
SECTION      ← value
2
HEADER       ← section name
9
$ACADVER     ← header variable
1
AC1032       ← version
0
ENDSEC
0
SECTION
2
ENTITIES
0
LINE         ← a line entity
8
Layer_1      ← layer name
10
100.0        ← X start point
20
200.0        ← Y start point
30
0.0          ← Z start point
11
300.0        ← X end point
21
200.0        ← Y end point
31
0.0          ← Z end point
0
ENDSEC
0
EOF

DXF Sections

Section	Content
HEADER	Drawing variables ($ACADVER, $EXTMIN, $EXTMAX, $INSUNITS, etc.)
CLASSES	Application-defined classes (extended entities)
TABLES	Layers, linetypes, text styles, dimension styles, blocks, viewports
BLOCKS	Block definitions (reusable geometry components)
ENTITIES	All drawing geometry (lines, arcs, text, inserts, etc.)
OBJECTS	Non-graphical objects (dictionaries, groups, layouts)
THUMBNAILIMAGE	Preview image embedded in the file

Common Entity Types

Entity	Description
LINE	2D/3D line segment
ARC	Circular arc
CIRCLE	Full circle
ELLIPSE	Ellipse
LWPOLYLINE	Lightweight polyline (2D, most common)
POLYLINE	Full 3D polyline with mesh support
SPLINE	NURBS spline curve
TEXT	Single-line text
MTEXT	Multi-line text
INSERT	Block reference (instance of a BLOCK definition)
HATCH	Filled area with pattern
DIMENSION	Dimension annotation
LEADER	Leader line annotation
IMAGE	Raster image reference
3DFACE	3D triangular/quadrilateral face
SOLID	Filled quadrilateral
ATTRIB	Block attribute instance

Coordinate Systems and Units

DXF/DWG stores coordinates in floating-point world units. The unit system is set by $INSUNITS in the HEADER:

Code	Unit
0	Unitless
1	Inches
2	Feet
4	Millimeters
5	Centimeters
6	Meters
14	Micrometers

User Coordinate System (UCS): custom coordinate system origin and orientation, stored per-viewport. Critical for 3D drawings and isometric views.

Paper Space vs. Model Space: AutoCAD maintains two environments — Model Space (where actual geometry is drawn at real-world scale) and Paper Space/Layout (where viewports frame model geometry for plotting at specific scales).

Layers, Colors, and Linetypes

Layers are the primary organizational structure in CAD drawings:

Each entity belongs to a layer.
Layers have color (AutoCAD Color Index 0-255, or True Color RGB), linetype, lineweight, and plot state.
Standard layer naming conventions (ISO, AIA, BS1192) ensure interoperability in collaborative projects.

AutoCAD Color Index (ACI): 255 standard colors where 1=red, 2=yellow, 3=green, 7=white/black. BYLAYER means the entity inherits the layer's color.

Linetypes: stored in LIN files and referenced by name (CONTINUOUS, DASHED, DASHDOT, CENTER, etc.). Custom linetypes with embedded text or shapes are also supported.

Blocks and External References (Xrefs)

Blocks: named collections of geometry stored in the BLOCKS section and instantiated via INSERT entities. Used for repeating symbols (doors, windows, bolts, trees). Blocks can have attributes (ATTDEF/ATTRIB) — text fields that can be filled per-instance.

Xrefs (External References): one drawing can reference other DWG files as if they were blocks, without embedding the geometry — the geometry is loaded from the external file at open time. Used for attaching base maps, structural drawings, and MEP (mechanical, electrical, plumbing) overlays in collaborative AEC workflows.

Dynamic Blocks (DWG only): blocks with parametric behavior — stretch, flip, rotate, array — controlled by block parameters and actions. Not supported in DXF.

Reading DXF and DWG Programmatically

ezdxf (Python, open source):

import ezdxf

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

# Iterate all LINE entities
for entity in msp.query("LINE"):
    start = entity.dxf.start    # Vec3(x, y, z)
    end = entity.dxf.end
    layer = entity.dxf.layer
    print(f"Line: {start} → {end} on layer '{layer}'")

# Create a new DXF
doc = ezdxf.new(dxfversion="R2018")
msp = doc.modelspace()
msp.add_line((0, 0), (100, 50), dxfattribs={"layer": "MY_LAYER"})
doc.saveas("output.dxf")

LibreDWG (C library, GNU): reads DWG files (from R2.6 to 2018). No write support for safety.

Open Design Alliance Teigha/ODA SDK (C++/C#/Java, commercial): full read/write for all DWG/DXF versions. Used by most commercial CAD alternatives.

Converting DXF and DWG

DWG → DXF: AutoCAD "Save As DXF", or free tools: DWG TrueView, ODA File Converter.
DXF → DWG: Same tools.
DXF/DWG → PDF: AutoCAD Plot dialog (PDF driver), Inkscape (DXF only), ezdxf + matplotlib.
DXF/DWG → SVG: Inkscape import (DXF), ezdxf r2000 → SVG, or Draftsight.
DXF → PNG/JPEG: ezdxf render with matplotlib backend, or convert via PDF.
PDF → DXF: PDF2CAD (commercial), Able2Extract, or Inkscape (for vector-only PDFs).
SKP (SketchUp) → DXF: SketchUp's File → Export → 3D Model → DXF.
IFC → DWG: via Revit export or BIM authoring tools.

DXF vs. DWG: Which to Use?

Scenario	Recommendation
Sharing with non-AutoCAD users	DXF — universal compatibility
Round-trip editing in AutoCAD	DWG — no data loss
Programming / scripting	DXF — open spec, many libraries
Dynamic blocks / xrefs	DWG — not fully preserved in DXF
Web display (SVG conversion)	DXF — easier to parse
Archive / long-term storage	DXF — open format
BIM (Building Information Modeling)	IFC instead — richer semantics

Best Practices

Save DXF as ASCII (not binary) for maximum compatibility with third-party tools.
Specify DXF version explicitly — R2010 or R2013 is a good balance of features and compatibility.
Purge unused elements before export: PURGE command removes unused layers, blocks, and linetypes.
Audit drawing before export: AUDIT fixes drawing database errors.
Bind xrefs before distributing DWG files to avoid broken references.
Use standard layer naming (ISO 13567 or AIA layer standards) for collaborative projects.
Set $INSUNITS correctly to avoid scale mismatches when importing.
Include a title block as a block reference with attributes for project metadata.
Use ezdxf for Python scripting — it is the best open-source DXF library.
Archive DXF alongside DWG for long-term accessibility when proprietary readers may not be available.

Related conversions

Frequent conversions across the catalogue:

Frequently Asked Questions

DWG is AutoCAD's native binary format with full feature support — dynamic blocks, xrefs, complex linetypes, and attributes are all preserved. It is proprietary and not publicly documented. DXF is Autodesk's documented interchange format — ASCII text that any CAD application can read. DXF loses or approximates some DWG features (dynamic blocks become static, xrefs may be bound or lost). Use DWG for all round-trip AutoCAD work and for features not representable in DXF. Use DXF when sharing with non-AutoCAD users, when programming tools to process CAD data (many open-source libraries support DXF but not DWG), for web display after conversion to SVG, or for long-term archival (open format, readable without a specific application).

DWG is AutoCAD's native binary formato com full feature support — dynamic blocks, xrefs, complexo linetypes, e attributes are all preserved. It is proprietary e not publicly documented. DXF is Autodesk's documented interchange formato — ASCII text that any CAD aplicativo can read. DXF loses ou approximates some DWG features (dynamic blocks become static, xrefs may be bound ou lost). usar DWG para all round-trip AutoCAD funcionar e para features not representable in DXF. usar DXF when compartilhando com non-AutoCAD users, when programming ferramentas to process CAD data (many open-source libraries support DXF mas not DWG), para web display depois conversion to SVG, ou para long-term archival (open formato, readable sem a specific aplicativo).

DWG is AutoCAD's native binary Format mit full feature support — dynamic blocks, xrefs, complex linetypes, und attributes are all preserved. It is proprietary und not publicly documented. DXF is Autodesk's documented interchange Format — ASCII text that any CAD Anwendung can read. DXF loses oder approximates some DWG features (dynamic blocks become static, xrefs may be bound oder lost). verwenden DWG für all round-trip AutoCAD work und für features not representable in DXF. verwenden DXF when sharing mit non-AutoCAD users, when programming Werkzeuge to process CAD data (many open-source libraries support DXF aber not DWG), für web display nach conversion to SVG, oder für long-term archival (open Format, readable ohne a specific Anwendung).

DWG is AutoCAD's native binary formato con full feature support — dynamic blocks, xrefs, complex linetypes, y attributes are all preserved. It is proprietary y not publicly documented. DXF is Autodesk's documented interchange formato — ASCII text that any CAD aplicación can read. DXF loses o approximates some DWG features (dynamic blocks become static, xrefs may be bound o lost). usar DWG para all round-trip AutoCAD work y para features not representable in DXF. usar DXF when sharing con non-AutoCAD users, when programming herramientas to process CAD data (many open-source libraries support DXF pero not DWG), para web display después conversion to SVG, o para long-term archival (open formato, readable sin a specific aplicación).

On KaijuConverter every file is processed inside an isolated container, encrypted in transit (TLS 1.3) and at rest, and automatically deleted after 60 minutes with multi-pass overwrite. We never train on, share, or analyze user content. For maximum privacy on extremely sensitive material, prefer offline tools (ImageMagick, FFmpeg, LibreOffice) that you control end-to-end.

The best open-source option is ezdxf for Python — a mature, well-documented library supporting DXF R12 through R2018. Install with pip install ezdxf, then use ezdxf.readfile("drawing.dxf") to load a file and doc.modelspace().query("LINE") to iterate entities. For C/C++, libdxfrw (used by LibreCAD) provides reading support. For Java, use Kabeja or the ODA SDK. For commercial applications requiring DWG read/write, the Open Design Alliance (ODA) SDK (Teigha) is the industry standard — it powers LibreCAD, FreeCAD, BricsCAD, and most AutoCAD alternatives. Note: reading DWG without a license is legally complex due to Autodesk's intellectual property claims.

The best open-source option is ezdxf para Python — a mature, well-documented library supporting DXF R12 através de R2018. Install com pip install ezdxf, then usar ezdxf.readfile("drawing.dxf") to load a arquivo e doc.modelspace().query("LINE") to iterate entities. para C/C++, libdxfrw (used by LibreCAD) fornece reading support. para Java, usar Kabeja ou the ODA SDK. para commercial aplicativos requiring DWG read/write, the abrir Design Alliance (ODA) SDK (Teigha) is the industry padrão — it powers LibreCAD, grátisCAD, BricsCAD, e most AutoCAD alternatives. Note: reading DWG sem a license is legally complexo due to Autodesk's intellectual property claims.

The best open-source option is ezdxf für Python — a mature, well-documented library supporting DXF R12 durch R2018. Install mit pip install ezdxf, then verwenden ezdxf.readfile("drawing.dxf") to load a Datei und doc.modelspace().query("LINE") to iterate entities. für C/C++, libdxfrw (used by LibreCAD) bietet reading support. für Java, verwenden Kabeja oder the ODA SDK. für commercial Anwendungen requiring DWG read/write, the öffnen Design Alliance (ODA) SDK (Teigha) is the industry Standard — it powers LibreCAD, kostenlosCAD, BricsCAD, und most AutoCAD alternatives. Note: reading DWG ohne a license is legally complex due to Autodesk's intellectual property claims.

The best open-source option is ezdxf para Python — a mature, well-documented library supporting DXF R12 a través de R2018. Install con pip install ezdxf, then usar ezdxf.readfile("drawing.dxf") to load a archivo y doc.modelspace().query("LINE") to iterate entities. para C/C++, libdxfrw (used by LibreCAD) proporciona reading support. para Java, usar Kabeja o the ODA SDK. para commercial aplicaciones requiring DWG read/write, the abrir Design Alliance (ODA) SDK (Teigha) is the industry estándar — it powers LibreCAD, gratisCAD, BricsCAD, y most AutoCAD alternatives. Note: reading DWG sin a license is legally complex due to Autodesk's intellectual property claims.

For 95% of use cases, yes — server-side ImageMagick, FFmpeg and LibreOffice produce identical output to the same tools on your laptop. Desktop software wins for: extremely large files (multi-GB), batch jobs of thousands of files, scripted pipelines, or content too sensitive to upload. KaijuConverter caps at 25 MB per file on the free tier (up to 2 GB on paid plans).

DXF files consist of pairs: an integer group code on one line, followed by its associated value on the next line. Group codes define the meaning of the value. Code 0 is an entity type or section marker (LINE, CIRCLE, SECTION, EOF). Code 1 is a primary string value. Codes 10/20/30 are X/Y/Z coordinates of point 1. Codes 11/21/31 are X/Y/Z of point 2. Code 8 is a layer name. Code 6 is a linetype name. Code 62 is an ACI color number. Codes 40-49 are floating-point values (radius, scale, etc.). Code 70 is an integer flag or count. This tag-value structure makes DXF parseable by simple line-pair readers without a formal grammar.

DXF arquivos consist of pairs: an integer group code on one line, followed by its associated value no next line. Group codes define the meaning of the value. Code 0 is an entity type ou section marker (LINE, CIRCLE, SECTION, EOF). Code 1 is a primary string value. Codes 10/20/30 are X/Y/Z coordinates of point 1. Codes 11/21/31 are X/Y/Z of point 2. Code 8 is a layer name. Code 6 is a linetype name. Code 62 is an ACI color number. Codes 40-49 are floating-point values (radius, scale, etc.). Code 70 is an integer flag ou count. This tag-value structure makes DXF parseable by simples line-pair readers sem a formal grammar.

DXF Dateien consist von pairs: an integer group code on one line, followed by its associated value auf dem next line. Group codes define the meaning des value. Code 0 is an entity type oder section marker (LINE, CIRCLE, SECTION, EOF). Code 1 is a primary string value. Codes 10/20/30 are X/Y/Z coordinates von point 1. Codes 11/21/31 are X/Y/Z von point 2. Code 8 is a layer name. Code 6 is a linetype name. Code 62 is an ACI color number. Codes 40-49 are floating-point values (radius, scale, etc.). Code 70 is an integer flag oder count. This tag-value structure makes DXF parseable by einfach line-pair readers ohne a formal grammar.

DXF archivos consist de pairs: an integer group code on one line, followed by its associated value en el next line. Group codes define the meaning del value. Code 0 is an entity type o section marker (LINE, CIRCLE, SECTION, EOF). Code 1 is a primary string value. Codes 10/20/30 are X/Y/Z coordinates de point 1. Codes 11/21/31 are X/Y/Z de point 2. Code 8 is a layer name. Code 6 is a linetype name. Code 62 is an ACI color number. Codes 40-49 are floating-point values (radius, scale, etc.). Code 70 is an integer flag o count. This tag-value structure makes DXF parseable by simple line-pair readers sin a formal grammar.

Most format conversions are lossy by design — JPG, MP3, MP4, WebP all discard perceptual data to save bytes. Going through a lossy intermediate compounds the loss. To minimize visible/audible drift: convert from the original master, choose a higher quality setting, and avoid converting back and forth between lossy formats.

AutoCAD has released new DWG format versions roughly every 3 years since 1982, adding new entity types and capabilities. DWG files have a version code in the first 6 bytes (e.g., AC1032 = DWG 2018). AutoCAD can open older versions but cannot open newer formats — AutoCAD 2019 cannot open a DWG saved in the 2024 format. Best practice: when sharing files with users on unknown AutoCAD versions, save in DWG 2010 (AC1024) format — it is broadly supported and includes all common entities. Only save in newer formats when you specifically need features introduced in those versions (e.g., TrueColor, underlay types). For DXF, R2013 is a safe choice.

AutoCAD has released new DWG formato versions roughly every 3 years since 1982, adding new entity types e capabilities. DWG arquivos have a version code no first 6 bytes (e.g., AC1032 = DWG 2018). AutoCAD can abrir older versions mas cannot abrir newer formatoos — AutoCAD 2019 cannot abrir a DWG salvo no 2024 formato. Best practice: when compartilhando arquivos com users on unknown AutoCAD versions, salvar in DWG 2010 (AC1024) formato — it is broadly suportado e inclui all common entities. Only salvar in newer formatoos when you specifically need features introduced in those versions (e.g., TrueColor, underlay types). para DXF, R2013 is a safe choice.

AutoCAD has released new DWG Format versions roughly every 3 years since 1982, adding new entity types und capabilities. DWG Dateien have a version code im first 6 bytes (e.g., AC1032 = DWG 2018). AutoCAD can öffnen older versions aber cannot öffnen newer Formate — AutoCAD 2019 cannot öffnen a DWG gespeichert im 2024 Format. Best practice: when sharing Dateien mit users on unknown AutoCAD versions, speichern in DWG 2010 (AC1024) Format — it is broadly unterstützt und beinhaltet all common entities. Only speichern in newer Formate when you specifically need features introduced in those versions (e.g., TrueColor, underlay types). für DXF, R2013 is a safe choice.

AutoCAD has released new DWG formato versions roughly every 3 years since 1982, adding new entity types y capabilities. DWG archivos have a version code en el first 6 bytes (e.g., AC1032 = DWG 2018). AutoCAD can abrir older versions pero cannot abrir newer formatoos — AutoCAD 2019 cannot abrir a DWG guardado en el 2024 formato. Best practice: when sharing archivos con users on unknown AutoCAD versions, guardar in DWG 2010 (AC1024) formato — it is broadly soportado y incluye all common entities. Only guardar in newer formatoos when you specifically need features introduced in those versions (e.g., TrueColor, underlay types). para DXF, R2013 is a safe choice.

Yes — KaijuConverter accepts multiple files in a single drop and returns a ZIP. For very large batches (thousands of files) consider command-line tools or our API: <code>find . -name "*.heic" -exec magick {} {.}.jpg \;</code> or similar one-liners scale to millions of files when run locally.