STL → FBX · FREE · NO UPLOAD
STL to FBX Converter — Print Files to Game-Ready 3D
Take a printable .stl toward Autodesk .fbx for Unity, Unreal and animation workflows. The browser writes OBJ or GLB — the hop Blender and engines actually import — then you export FBX on the desktop. No upload.
What it does:converts STL (print format — pure triangles) onto the path to FBX (game/animation interchange). This tab indexes the mesh and writes Wavefront OBJ or binary GLB. It does not emit .fbx; Autodesk's writer is a desktop SDK.
Why you need it: you have a 3D-print model and want it in Unity or Unreal as a game asset. Engines import FBX natively. STL is a triangle soup slicers love and editors tolerate poorly.
How it works: three.js parses the STL in this tab and exports OBJ or GLB, 100% client-side. Open that file in Blender (or Autodesk FBX Converter) and export FBX. Disconnect the network after the page loads — conversion still runs.
Conversion specs
| Input format | STL (binary or ASCII — print mesh, triangles only) |
| Browser output | Wavefront OBJ or GLB (binary glTF) — not .fbx |
| FBX finish step | Blender File → Export → FBX, or Autodesk FBX Converter |
| Animation / skeleton | None — STL has no bones; result is a static mesh |
| Materials | STL has none; OBJ has no MTL; GLB gets a default PBR material |
| Unit mapping | Numbers copied as-is — set FBX export units to match the engine |
| File size limit | Device RAM only — no server limit |
| Processing | 100% client-side via three.js (OBJExporter / GLTFExporter) |
| Cost | Free, unlimited conversions, no account required |
From a print mesh to a Unity or Unreal asset
STL is the language of slicers: a list of triangles, no UVs required, no scene graph. FBX is Autodesk's exchange format — the file Maya, Blender, Unity and Unreal pass around because it can hold a mesh plus, when the source has them, a skeleton, clips and materials. A print model has none of that extra payload. The conversion is still useful: you get the same geometry into the container the engine's importer is built for.
A browser cannot write FBX. The Autodesk SDK is native code; three.js can read FBX (see FBX to STL) but does not export it. So this page does the triangle hop in-tab — STL → OBJ or GLB — and you do the last container change on the desktop. That is not a workaround advertised as a full converter; it is the actual pipeline.
- Drop the STL on the converter above. Wait for the preview so you can confirm triangle count and bounding-box size. Download OBJ for a Blender/Maya import, or GLB if you also want a web-ready copy. Nothing is uploaded.
- Open the OBJ (or GLB) in Blender. Check scale against the bounds you saw here — slicers assume millimeters; Unity often wants meters; Unreal wants centimeters. Apply scale, then File → Export → FBX. In the exporter, set the unit and axis (Y-up vs Z-up) to match the engine. Autodesk FBX Converter can also wrap OBJ as FBX if you do not use Blender.
- Import that FBX into Unity or Unreal as a static mesh. You will not get a rig, clips or authored materials from a print file — those are added in the DCC if you need them. If you only needed an editable mesh and not an engine file, stop at OBJ and skip FBX; that is the STL to OBJ converter. For a webpage instead of an engine, use STL to GLB.
That is the whole pipeline: STL in the browser, OBJ or GLB out, FBX from a desktop tool, engine import last. The mesh does not grow a skeleton on the way through.
What survives the hop
| In the STL | After OBJ/GLB → FBX |
|---|---|
| Triangle geometry | Kept — same vertices, now in an FBX mesh node |
| Vertex colors (rare in STL) | Usually dropped; re-assign in the DCC |
| UVs / materials / textures | STL has none — add them in Blender before FBX export |
| Skeleton, skin weights, clips | None exist — static mesh only |
| Scene hierarchy | Single mesh (or a small node tree from GLB) |
| Units (unspecified in STL) | Numbers copied as-is; set FBX export unit for the engine |
Going the other way — a game asset toward the printer — is FBX to STL. New to the container itself? What is an FBX file covers ASCII vs binary, animation, and how FBX compares to OBJ and glTF.
FAQ
Can this page write an FBX file in the browser?+
No. Autodesk's FBX SDK is a desktop library; this site does not ship it, and three.js has an FBX loader, not a writer. Drop an STL here and download OBJ or GLB — those are the formats the browser can actually emit. Finish the hop to .fbx in Blender (File → Export → FBX) or Autodesk FBX Converter. The geometry is the same triangles; only the container changes on the desktop.
Why convert STL to FBX at all?+
STL is a print format: a triangle list with no materials, no bones, no scene graph. Unity and Unreal import FBX as the default game-asset container. If you sculpted or sliced a model as STL and now want it as a prop, character base, or environment piece in an engine, you need that hop. This page gets you an editor-friendly mesh (OBJ) or a web/engine-friendly glTF (GLB) without uploading the file; Blender then writes the FBX the engine expects.
Will the FBX include animation or a skeleton?+
Not from an STL. STL stores only triangles. There are no bones, clips, blend shapes or materials to carry over. The result is a static mesh in whatever pose the print file already had. If you need a rig, you add that in Maya, Blender or Mixamo after the mesh is in a DCC — converting the container does not invent a skeleton.
Is my STL uploaded anywhere?+
No. The converter parses the STL with JavaScript in this tab and writes OBJ or GLB locally. There is no upload endpoint. Load the page, disconnect from the internet, and the conversion still works. The later Blender/FBX Converter step is also local if you run those tools on your machine.
Should I download OBJ or GLB as the intermediate?+
OBJ is the usual Blender/Maya import for a static mesh — indexed vertices, no extra scene wrapper. GLB is binary glTF: smaller, has a default PBR material so it renders in viewers, and some engine pipelines accept it directly. If the destination is Unity or Unreal via FBX, OBJ → Blender → FBX is the boring, reliable path. If you only needed a web preview, stop at GLB and skip FBX entirely — use the STL to GLB page.
What about units and scale?+
Numbers copy as-is. Slicers treat STL values as millimeters; Unity often treats FBX as meters or centimeters depending on the exporter; Unreal defaults to centimeters. Check the bounding-box readout under the preview. A 40 mm bracket stored as 40 in the STL must be scaled on FBX export (Blender: apply scale, set FBX unit) or it arrives as a 40-meter wall. Trust the numbers on this page, then set the FBX exporter's unit to match the engine.