Turn an OBJ mesh into an STL for your slicer. Set its size, inspect both models and download the geometry — all in your browser.
Free · no generation credits
Your model stays on your deviceUp to 100 MB · 1 million triangles
Source file
OBJ
OBJ → STL
Converted geometry
STL
Your converted model will appear here.
STL has no unit metadata. Set the longest side in millimeters and check it in your slicer.
A binary STL with triangulated geometry at your chosen size. Materials and textures are not included.
REAL CONVERSION EXAMPLE
One house. OBJ in, STL out.
The roof, walls and windows become triangle geometry. The example is scaled to a 100 mm longest side; check open boundaries before using it in a print workflow.
OriginalOBJ
OBJ wireframe · faces triangulated during export
ConvertedSTL
STL surface · 100 mm longest side · no materials
Drag either model to rotate · zoom to inspect · switch to wireframe
exported triangles
1,764
longest side in this demo
100 mm
binary STL output
86.2 KB
A licensed sample converted with this tool. This is a format demo, not an AI-generated or verified print result. Model source & license · drummyfish · CC0 1.0
OBJ vs STL: a mesh for editing or a surface for slicing
Both formats describe surfaces, but they package geometry and appearance differently. Choose STL when the next stage needs triangle geometry at a known size.
Source formatOBJ
Wavefront OBJ
A text-based surface description built from vertex coordinates and faces. It is widely used to move meshes between modeling applications.
Structure
Vertices can be shared by faces; polygon faces are possible. This converter reads mesh faces and triangulates them, ignoring line and point primitives.
Color & texture
OBJ can reference an MTL library, UV coordinates and separate texture images. Those are format capabilities; this converter exports geometry without that package.
Scale & units
An OBJ generally does not declare a dependable physical unit. Check import scale and a known measurement in your next application.
Best suited to
Static mesh exchange and shape editing. Use an editor to prepare topology, UVs or materials for your final purpose.
Output formatSTL
STL triangle surface
A collection of triangles describing the outside of a model. It is a common handoff format for 3D printing slicers.
Structure
Each triangle stores its own corner coordinates and face normal. Fomrix writes binary STL; it does not export CAD sketches or design history.
Color & texture
Standard STL has no texture image, UV layout or material package. A gray preview is expected even if the original was colorful.
Scale & units
STL does not store a unit. This tool writes the size you choose as millimeter coordinates; confirm it on import into a slicer.
Best suited to
Taking a verified surface into a slicer. An STL extension alone does not make an open or thin mesh printable.
Choose a real size before exporting STL
The longest side sets the overall scale; the other two dimensions keep their proportions. Explore the measured sample below before choosing a size for your own file.
Estimated sample dimensions (mm)
All axes × the same scale factorAn explanation using the sample's measured proportions. This does not change the converter settings above or determine wall thickness.
Color is not missing geometry
The house still has its roof and walls after conversion, even though STL has no material package. Inspect the wireframe to separate shape from appearance.
A plain surface is expected
Colors and texture images belong to the source workflow. Standard STL cannot carry them, so their absence is not a conversion failure.
Not a solid-building operation
An open wall remains open. Converting polygon faces does not add a floor, fill holes, thicken shells or produce a CAD solid.
From your file to the next step
Select a step to see what happens. Try the actual conversion above when you are ready.
