Free online SKP to 3MF converter

3MF is required by many modern 3D-printing workflows and slicers because it can retain print-oriented metadata that STL cannot. Converting an SKP model makes SketchUp geometry usable in a 3MF-compatible slicer, printer application, or archive.

What the SKP format is

SKP is SketchUp’s native 3D model format, created by SketchUp desktop and web applications. It stores scenes, components, groups, layers or tags, cameras, dimensions, materials, textures, and editable SketchUp geometry.

SKP files commonly contain architectural models, interior layouts, furniture, product concepts, and other design work. The format is optimized for editing in SketchUp rather than direct 3D printing, so a model may contain open surfaces, overlapping faces, construction geometry, hidden objects, or non-printable details.

What the 3MF format is

3MF is a 3D-printing and manufacturing format based on a packaged set of XML files. It can store one or more mesh objects, units, colors, materials, textures, build placement, and application-specific print information.

Compared with STL, 3MF can preserve units and richer object or material data in one package. Slicers such as PrusaSlicer, Bambu Studio, OrcaSlicer, and UltiMaker Cura can import 3MF, although support for application-specific print settings varies. A 3MF file is not automatically editable as a native SketchUp model; it normally contains triangulated mesh geometry.

How to convert SKP to 3MF

Method 1: use the built-in online converter

1. Open the SKP-to-3MF converter on 101convert.com.
2. Upload the .skp file and select 3MF as the output format.
3. Start the conversion, then download the resulting .3mf file.
4. Open the result in your slicer and check the model dimensions, orientation, and object count before slicing.

This route does not require software installation. It is most suitable when the SKP contains ordinary mesh geometry and does not depend on SketchUp-specific scenes, components, or texture behavior.

Method 2: export STL from SketchUp, then save as 3MF

1. Open the model in SketchUp and remove construction lines, guides, hidden objects, and geometry that should not be printed.
2. Check that each printable part is a closed solid. SketchUp’s Entity Info panel identifies groups or components recognized as solids; repair gaps, reversed faces, internal faces, and intersecting shells before export.
3. Select the required geometry, or leave the whole model selected if every visible part should be converted.
4. Choose File → Export → 3D Model, select STL, and export the file. In SketchUp versions that offer STL export options, use binary STL unless an ASCII file is specifically required, and set the unit to match the model.
5. Open the STL in a 3MF-capable desktop application. Microsoft 3D Builder can import STL and use Save as → 3MF; PrusaSlicer can import the STL and save the project or exported model as .3mf. FreeCAD can also import the mesh and export it through its Mesh workbench when 3MF export is available in the installed version.
6. Reopen the saved 3MF in the target slicer and verify scale, orientation, watertightness, and per-part placement.

Quality and compatibility limitations

The conversion changes SketchUp’s editable faces into a tessellated triangle mesh. Groups, components, scenes, dimensions, SketchUp styles, section planes, and most editing metadata do not survive the STL-based workflow. Textures and complex SketchUp materials are also commonly lost; 3MF can carry material and texture data, but only when the conversion tool explicitly maps them.

Scale is a frequent failure point because STL does not reliably carry unit information. Confirm the model’s intended units during STL export and measure a known dimension after opening the 3MF. A model that imports at 25.4 or 0.03937 times its intended size usually has an inch-to-millimeter or millimeter-to-inch mismatch.

For printing, every shell should be closed, have consistent face normals, and contain walls thick enough for the selected nozzle or manufacturing process. A 3MF container does not repair invalid geometry by itself; run the slicer’s repair or mesh-analysis tool and inspect the layer preview before producing the final file.