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Your STL is converted on your own computer and never uploaded, so client parts and unreleased designs stay with you.
STL to FBX Converter for Game Engines and Blender
Bring a 3D print model or scan into a game engine or animation app. The STL becomes a binary FBX at its true size, standing upright, with smooth shading and crisp edges.
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Converted in your browser. Files are never uploaded.
Continue with your model
Check the FBX you just made, or convert the STL for other apps.
How to convert STL to FBX
- 1
Add your STL files
Drop one or more .stl files, binary or ASCII. Each is read in your browser and placed on the plate with its size.
- 2
Check the size
STL numbers are read as millimeters, the 3D printing standard. If a model arrives far too big or small, turn on Resize longest side and enter the size you want.
- 3
Download the FBX
Save a binary FBX 7.4 file in centimeters with Y up, ready for Blender, Unity or Unreal. Several STL files download together as a ZIP.
Why use this STL to FBX converter
Built for taking print models and scans into real-time 3D.
Smooth shading, crisp edges
STL stores one flat normal per triangle. The FBX gets normals that shade curves smoothly and keep edges sharper than 40 degrees crisp.
True size, standing upright
Millimeters become centimeters, FBX's own unit, and Z-up becomes Y-up, so the model arrives at its real size and right way up.
One connected mesh
STL repeats every corner for each triangle. The FBX shares them, so Blender sees one connected mesh you can edit, and the file is usually smaller.
What carries over from STL to FBX
STL holds nothing but triangles, so there is little to lose. The FBX adds what engines expect: a name, normals and a material slot.
Kept
- Every triangle of the surface
- Real size, converted to centimeters
- The file name, as the object name
- Upright orientation, with Z-up turned to Y-up
Left behind
- Color: STL has none, so the FBX gets a plain gray material
- UV coordinates: STL has none, so unwrap before texturing
- The original placement: the model is centered on the ground
- Per-facet colors that some tools write into binary STL
STL to FBX guide
From print file to game asset: what changes, triangle counts and importing into Blender, Unity and Unreal.
From a print file to a game asset
STL is a print format: a list of triangles in millimeters with Z up and no names, colors or texture coordinates. FBX is an exchange format for 3D apps and game engines, with named objects, normals, materials and a stated unit and up axis. The converter fills in what FBX needs, welds the repeated corners into a connected mesh and writes the unit and axes into the file.
What it cannot invent is texture coordinates. To paint or texture the model, unwrap it first. In Blender, Smart UV Project in the UV menu of Edit Mode gives a quick, usable layout.
Unit
- STL
- Not stored, read as mm
- FBX from this tool
- Centimeters, stated in the file
Up axis
- STL
- Z-up in slicers
- FBX from this tool
- Y-up, stated in the file
Vertices
- STL
- Repeated for every triangle
- FBX from this tool
- Shared, one connected mesh
Normals
- STL
- One per triangle
- FBX from this tool
- Per corner, smooth or sharp
Name and material
- STL
- None
- FBX from this tool
- File name and a gray material
Triangle count and real-time performance
Print models are often far denser than game assets. A scanned or sculpted STL can carry hundreds of thousands of triangles, which a slicer handles easily but which weigh on a real-time scene, especially on mobile and VR.
The triangle count shows under the preview. If it is high for how the model will be used, Blender's Decimate modifier reduces it before you take the FBX into the engine, and keeps the silhouette close to the original.
Centimeters and Y-up in Blender, Unity and Unreal
An FBX file states its own unit and up axis. This converter writes centimeters, the unit FBX uses natively, with Y pointing up, the same defaults Blender's own FBX exporter writes. Each app converts from there, so the model keeps the size shown in the readout above.
The model is centered on the origin with its lowest point at Y = 0. Objects in one file keep their layout, while separate files are each centered on their own.
Blender
- On import
- Converts centimeters to its meters and Y-up to Z-up automatically
- What you see
- Correct dimensions. The object can show scale 0.01 and a 90 degree X rotation; Ctrl+A, All Transforms bakes them in
Unity
- On import
- Convert Units, on by default, maps 1 cm in the file to 0.01 m
- What you see
- Correct size in meters, already Y-up
Unreal Engine
- On import
- Works in centimeters natively and turns Y-up into Z-up
- What you see
- Correct size. If the model faces the wrong way, turn it about Z in the import options or after placing it
Import tips for Blender, Unity and Unreal
Blender: use File, Import, FBX with the default settings. Each object arrives as its own mesh with a gray material, and the file's custom normals keep the hard edges.
Unity: drag the .fbx into the Assets folder. Leave Convert Units on and Normals set to Import so the crisp edges survive, then assign your own material on the Mesh Renderer.
Unreal Engine: import the .fbx as a Static Mesh. A file with several objects becomes several static meshes unless you turn on the option to combine meshes in the import dialog.
STL to FBX questions
Answers about textures, size, orientation, batches and privacy.
Is the STL to FBX converter free and private?
Yes. It is free with no sign-up, and the conversion runs in your browser, so your STL never leaves your computer.
Why does my FBX have no colors or textures?
STL stores only shape, so there is nothing to carry over. The FBX gets one gray material per object. Unwrap UVs in Blender, for example with Smart UV Project, before you add textures.
Will the model be the right size in Unity or Unreal?
Yes, if the STL was modeled in millimeters, as print files are. The FBX is written in centimeters with the unit stated, so a 50 mm part is 0.05 units in Unity, which works in meters, and 5 units in Unreal, which works in centimeters.
Which way is up in the FBX?
Z-up in the STL becomes Y-up in the FBX, the axis Unity and Maya use. Blender and Unreal turn it back into their own Z-up on import, so the model stands the way it stood in your slicer.
Can I convert several STL files at once?
Yes. Drop them together and download a ZIP with one FBX per STL. Each FBX uses its file name as the object name.