Convert DWG to OBJ in your application
3D InterOp is a CAD interoperability SDK that lets your software read DWG files and write OBJ, generating the OBJ mesh from the geometry it reads, with tessellation settings your application controls.
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 OBJ
- Mixed geometry → triangle mesh
- C++ / C# APIs
DWG to OBJ at a glance
DWG can mix exact solids and facets; OBJ stores triangles only, so the whole model is tessellated when it is written.
| DWG (source) | OBJ (target) | |
|---|---|---|
| Full name | AutoCAD Drawing | Wavefront OBJ |
| Standard / owner | Autodesk | Open format |
| File extensions | .dwg | .obj |
| Geometry | 2D drawings and 3D data | Polygon mesh |
| Assemblies / structure | Blocks and layers | No assembly 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 OBJ.
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Changes
Geometry is tessellatedThe exact DWG B-Rep is replaced by a triangle mesh, generated by 3D InterOp from the exact geometry it reads. Accuracy depends on the tessellation settings your application uses.
Why software vendors add DWG to OBJ conversion
Lightweight review
OBJ carries tessellated geometry that opens much faster than the full CAD model, so design reviews and digital mockups stay responsive.
Sharing outside engineering
Marketing, training and sales teams rarely have CAD software. A OBJ file gives them the shape in a format their tools can open.
Easier handling of large assemblies
Without exact surfaces and feature data, OBJ files are easier to transfer and display, even for large assemblies.
Things to check before you ship
- The OBJ writer is available through the UConnect interface only.
- Supported DWG input: DXF/DWG 2.5 to 2027.
- A DWG file that only contains 2D drawings has no 3D geometry to write.
- Test tessellation settings on your heaviest parts: finer meshes mean larger files.
- 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 OBJ (.obj) file?
OBJ is a simple, widely supported text format for polygon meshes, created by Wavefront. It describes vertices, faces and texture coordinates, with materials in a separate .mtl file.
Frequently asked questions
3D InterOp tessellates the geometry it reads from DWG when it writes OBJ. Your application sets the tolerances, so it controls the trade-off between accuracy and file size.
The OBJ writer is available through the 3D InterOp UConnect interface.
Then there is no 3D geometry to write to OBJ: 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.
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Building software that needs to convert DWG to OBJ?
3D InterOp is an SDK that lets your application read DWG and write OBJ alongside 30+ CAD and BIM formats.