Free online DWG to 3MF converter

A 3D printer slicer or fabrication application may require a .3mf model instead of a CAD drawing. Converting a suitable DWG makes its 3D geometry available for slicing, printing, or exchange without installing software; 101convert.com provides this conversion for free.

What the DWG format is

DWG is a proprietary binary CAD format associated with Autodesk AutoCAD and supported by applications such as BricsCAD, DraftSight, and Civil 3D. Architects, engineers, surveyors, and manufacturing designers use it for drawings that can contain 2D linework, layers, dimensions, blocks, annotations, surfaces, meshes, and 3D solids.

A DWG is not automatically a printable 3D model. Floor plans, elevations, dimensions, and other 2D geometry require additional modeling: closed profiles must be extruded, or surfaces must be converted into closed 3D solids, before they can produce a useful 3MF object.

What the 3MF format is

3MF (3D Manufacturing Format) is a package format for additive manufacturing and 3D model exchange. A 3MF package uses XML-based resources to store one or more triangle meshes, units, object relationships, colors, materials, and optional thumbnails or textures. Slicer-specific extensions can also store layouts and print settings.

Unlike a basic STL file, 3MF can keep multiple objects, color information, units, and related resources in one package. It is still primarily a mesh format: DWG layers, dimensions, parametric constraints, blocks, and editable CAD history do not remain as editable CAD features.

Direct conversion with Rhino

Rhino is suitable when the DWG already contains usable 3D geometry and the installed Rhino version supports 3MF export.

1. Open Rhino and select File → Import to load the .dwg file. Confirm the drawing units during import.
2. Hide or remove dimensions, text, title blocks, construction lines, and other objects that should not appear in the printed model.
3. Check the 3D geometry for open edges, self-intersections, duplicate faces, overlapping parts, and zero-thickness surfaces. Rhino's ShowEdges command can locate naked edges.
4. Join surfaces and repair the geometry until each intended part is a closed solid or closed polysurface. This produces a more reliable mesh for printing.
5. Select the required objects and choose File → Export Selected. Choose 3MF (*.3mf), then set the correct units and mesh-detail options.
6. Open the result in a slicer and check its scale, orientation, object count, and manifold status before generating printer code.

Convert through STL

Use an intermediate STL when AutoCAD or another compatible CAD application can export the 3D model as STL but cannot write 3MF directly.

1. Open the DWG in AutoCAD, BricsCAD, or another compatible CAD program and select only the finished 3D solids or surfaces intended for export.
2. Use the application's STL export command, commonly available under Output → Export or File → Export, and choose STL. Select binary STL when available to reduce file size.
3. Set the tessellation quality before export. A coarse mesh makes curved surfaces visibly faceted; an excessively fine mesh creates a large file without necessarily improving the printed result.
4. Import the STL into PrusaSlicer, OrcaSlicer, Cura, Microsoft 3D Builder, or another application that can write 3MF. Confirm the dimensions because STL does not reliably store unit information.
5. Save the imported model as model.3mf. In a slicer, the result may be a 3MF project containing the model, placement, and print settings rather than a geometry-only package.

Convert without installing software

On 101convert.com, select DWG as the input format and 3MF as the output format, upload the file, start the conversion, and download the resulting .3mf file when processing finishes. Use this route only for files suitable for the service's privacy policy, and inspect the downloaded model in a 3D viewer or slicer because unsupported DWG entities, layers, materials, or solids may be discarded.

Quality and compatibility limits

• 2D geometry needs modeling: Lines and arcs from a floor plan do not become walls or a printable object merely because the output extension is .3mf. Create closed profiles and extrude them, or model the required solids first.
• Units require verification: DWG may contain a drawing-unit setting, while STL normally has no dependable unit metadata. Confirm millimeters, inches, or the intended unit at import, export, and slicer stages.
• CAD surfaces become triangles: Curves and analytic surfaces are approximated by a mesh. Increase resolution where curved surfaces need a smoother appearance, while checking file size and slicer performance.
• Invalid solids cause print errors: Gaps, reversed normals, intersecting shells, duplicate faces, and zero-thickness surfaces can create missing regions or invalid toolpaths. Repair the CAD model before export; slicer repair tools should be treated as a final check, not a substitute for modeling.
• 3MF support varies: PrusaSlicer, OrcaSlicer, and Cura can import 3MF, but applications differ in their support for materials, textures, thumbnails, print profiles, and vendor-specific extensions. A receiver may open the mesh while ignoring project settings.
• Scale and orientation may change: A successful file conversion does not guarantee the correct physical size or print orientation. Measure a known dimension in the receiving application before slicing.