Convert DWG to IFC in your application
3D InterOp is a CAD interoperability SDK that lets your software read DWG files and write IFC, mapping geometry and structure from one model format to the other.
Spatial does not offer an online converter or a desktop conversion app. 3D InterOp is a component that software vendors embed in their own products.
- Reads DWG · Writes IFC
- Mixed geometry → mixed geometry
- C++ / C# APIs
DWG to IFC at a glance
Both formats can hold exact solids and faceted geometry. The translation is about how geometry, structure and properties map from DWG to IFC.
| DWG (source) | IFC (target) | |
|---|---|---|
| Full name | AutoCAD Drawing | Industry Foundation Classes |
| Standard / owner | Autodesk | buildingSMART, ISO 16739 |
| File extensions | .dwg | .ifc, .ifczip |
| Geometry | 2D drawings and 3D data | Exact B-Rep and tessellated geometry |
| Assemblies / structure | Blocks and layers | Yes: spatial and element hierarchy |
| 3D InterOp support | Read; write drawings only | Read and write |
What's preserved, what changes
Here is what your application can expect to carry across from DWG to IFC.
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Preserved
Exact geometryExact B-Rep read from DWG is written to IFC as exact geometry.
Why software vendors add DWG to IFC conversion
Open BIM deliverables
Many projects specify IFC deliverables. Writing it lets your users meet those requirements from your software.
Coordination and clash detection
Coordination tools gather models from every discipline in IFC. Your users can contribute without a round trip through another tool.
Facility and asset data
Owners and operators often receive building data as IFC for asset management after handover.
Things to check before you ship
- Written IFC versions: IFC2x3 to IFC4x3 ADD2 (.ifc).
- Exact B-Rep needs IFC4 or later; IFC2x3 files only get tessellation.
- Supported DWG input: DXF/DWG 2.5 to 2027.
- A DWG file that only contains 2D drawings has no 3D geometry to write.
- Validate a sample of translated files in the target system your users actually work with.
Working with Spatial was a real milestone for us: Thanks to the powerful 3DInterOp library, we were able to successfully bring our complex CAD-based solutions to the cloud while remaining flexible to meet individual customer requirements. For us, Spatial is not just a technology partner, but a true enabler of our product strategy.
Dr. Arno Michelis, Founder, Simus Systems
Read the Case StudyAbout the formats
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Source format
What is a DWG (.dwg) file?
DWG is the native file format of Autodesk AutoCAD, used for 2D drawings and 3D models. It is one of the most widespread formats for technical drawings.
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Target format
What is an IFC (.ifc) file?
IFC is the open, vendor-neutral standard for exchanging building information models, maintained by buildingSMART and published as ISO 16739. It carries building elements with their geometry, properties and relationships.
Frequently asked questions
The exact B-Rep that 3D InterOp reads from DWG is written to IFC; parts stored only as facets stay faceted.
Write IFC4 or later to keep exact B-Rep: IFC2x3 files only get tessellation. 3D InterOp writes IFC2x3 to IFC4x3 ADD2.
Then there is no 3D geometry to write to IFC: 3D InterOp needs 3D content in the DWG file for this conversion.
Both the 2D content (drawing sheets) and the 3D data stored in the file.
No. 3D InterOp writes drawing sheets to DXF and DWG, but 3D export to these formats isn’t supported. To send 3D data back to AutoCAD users, write a neutral 3D format such as STEP.
3D InterOp reads DXF/DWG 2.5 to 2027.
3D InterOp writes IFC2x3 to IFC4x3 ADD2 (.ifc).
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Building software that needs to convert DWG to IFC?
3D InterOp is an SDK that lets your application read DWG and write IFC alongside 30+ CAD and BIM formats.