Free online DWG to IGS converter

Convert DWG geometry to IGES for CAD, CAM, inspection, and legacy-system exchange.

Convert DWG to IGS online - free

.dwg .igs

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How to convert dwg to igs file

September 14, 2026
CAD formats
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A receiving CAD, CAM, inspection, or legacy engineering system may require IGES instead of DWG for geometry exchange. Converting creates a neutral file that can be shared with suppliers or imported into software that does not support DWG.

What the DWG format is

DWG is Autodesk's proprietary CAD drawing format, used by AutoCAD and many compatible applications. It can contain 2D lines, arcs, text, dimensions, hatches, blocks, layers, layouts, external references, 3D surfaces, and 3D solids.

Architects, civil engineers, mechanical designers, manufacturers, contractors, and surveyors commonly use DWG for plans, construction documents, manufacturing drawings, and 3D models. Applications such as BricsCAD, DraftSight, Rhino, and other engineering systems can read or write some DWG revisions, but support for entities and newer format versions varies.

What the IGS format is

IGS, also written as IGES and normally saved with the .igs or .iges extension, is the Initial Graphics Exchange Specification. It is a neutral, usually ASCII-based format for exchanging CAD curves, wireframes, surfaces, and some boundary-representation solids.

IGES is supported by many CAD, CAM, CNC, inspection, and older engineering systems. It transfers geometric results rather than native feature history, parametric constraints, sketches, assemblies, materials, or most application-specific metadata. Many systems handle IGES surfaces more reliably than IGES solid entities, so the best export type depends on the receiving software.

How to convert DWG to IGS

Using Rhino

Rhino is a practical desktop option for importing DWG and exporting selected curves, surfaces, and solids as IGES.

Copy the original DWG and open the copy in Rhino.
Choose File → Import, select AutoCAD Drawing, and open the .dwg file.
In the import settings, retain the source units and import only the required layers. Exclude unnecessary layouts, annotations, hatches, and construction geometry.
Check the result for missing external references, proxy objects, duplicate entities, incorrect scale, and broken curves. Rhino commands such as _SelBadObjects, _Join, and _ShowEdges can help identify geometry problems.
Select the curves, surfaces, or solids to export, then choose File → Export Selected and select IGES (*.igs; *.iges).
Choose an IGES entity type supported by the destination application. A surface-based export may be more compatible than a solid export, but it can require stitching or healing after import.
Open the IGS file in the target system and verify units, dimensions, orientation, surface continuity, and solid closure.

A 2D DWG produces 2D IGES entities. Exporting it does not create a 3D model; the source must already contain usable 3D surfaces or solids.

Using a CAD translator

CAD Exchanger Desktop can translate supported DWG geometry to IGES. Open the DWG, inspect the model tree, select the required bodies or components, choose IGES as the output format, set units and available healing or export options, and save the file. Verify support for the specific DWG revision and entity types in the installed version before processing a project.

If a translator cannot read the DWG revision, use Autodesk DWG TrueView's conversion tools or the ODA File Converter to create a compatible DWG version, then retry the import. These utilities change the DWG version; they do not themselves provide a general DWG-to-IGES conversion workflow.

Using an online converter

CAD Exchanger Cloud is an option for non-confidential files when its current format list accepts the required DWG input and IGES output. Upload the file, choose IGES, download the result, and validate it in the destination CAD or CAM system.

Online conversion can fail with proxy objects, unresolved xrefs, large assemblies, unsupported 3D entities, or files that depend on external resources. Do not upload proprietary designs unless the service and your organization's security policy permit it.

Quality and compatibility limits

Geometry only: Text, dimensions, layouts, layers, blocks, constraints, and feature history may be omitted or reduced to basic geometry. IGES is not a native DWG replacement.
External references: Xrefs, image underlays, SHX fonts, and proxy objects may not be embedded or supported. Bind or resolve required references and include dependent resources before conversion.
Units: DWG unit metadata can be undefined or inconsistent with the modeled dimensions. Measure a known feature after import and after IGES export rather than relying only on unit settings.
Surface repair: Gaps, duplicate faces, reversed normals, self-intersections, and non-manifold edges can prevent a receiving system from creating a solid or using the model for machining. Run its geometry-check and healing tools.
Neutral-format choice: STEP is generally preferable for modern 3D solids and assemblies when both systems support it. DXF is often more suitable for 2D drafting, profiles, and cutting workflows.

DWG vs IGS: format comparison

How the DWG and IGS formats compare on the properties that matter most for this conversion.

Comparison of the DWG and IGS file formats
Property	.DWG AutoCAD Drawing	.IGS Initial Graphics Exchange Specification
Dimensions	Both	3D
Geometry	Both	Both
Layers	Yes	No
Materials	Limited	Limited
Plain-text readable	No	No
Operating system support	Wide	Wide
Typical file size	Large	Medium
Open standard	Partly open	Partly open
Developer	Autodesk	IGES/PDES organization (later managed by various standards bodies, including ANSI/ASME)
MIME type	application/acad	—

Open DWG file Open IGS file

Frequently asked questions

Is the DWG to IGS converter free?

Yes, converting DWG to IGS on 101convert.com is completely free. No registration, email address or installation is required. If you need a higher file size limit or want to convert more files at once, see our plans.

How large can my DWG file be?

You can upload DWG files up to 500 MB and convert up to 20 files at once in a single batch.

What happens to my uploaded files?

Files are processed automatically and deleted from our servers within a few minutes after conversion. We never view or share your files.

Do I need to install any software to convert DWG to IGS?

No. The DWG to IGS conversion runs entirely online in your browser and works on Windows, Mac, Linux, Android and iPhone.

Did the conversion fail?

In most cases, the cause is an incorrect file format. Please upload a valid DWG file for this DWG to IGS conversion. Occasionally, the issue may be on our side. We analyze recurring conversion failures and disable or fix the converter if we detect a defect.

Will my DWG layers and editable CAD features be preserved in IGES?

The geometric shape may be preserved, but DWG layers, blocks, annotations, and parametric feature history are not reliably carried over as editable native features. IGES is mainly an exchange format for geometry, so the result may need healing or rework in the receiving CAD system.

Does DWG to IGS keep 3D solids and curved surfaces?

It can preserve supported 3D solids and curved surfaces, but some conversions represent them as separate IGES surfaces or wireframe entities instead. Unsupported objects, proxies, meshes, hatches, and drafting annotations may be omitted or changed.

Why does my DWG to IGS conversion have the wrong scale or units?

IGES and DWG can store or interpret units differently, so the receiving CAD program may assign the wrong unit scale if the source units are unclear. Check the DWG drawing units and the IGES import units, and verify a known dimension after conversion.

Will the IGES file look exactly like the original DWG?

No, the model geometry may transfer while dimensions, text styles, layouts, display settings, and other drafting details can change or disappear. The result is generally less editable than the original DWG and is best checked for gaps, missing faces, and invalid surfaces before manufacturing or inspection.

dwg to iges dwg to image

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