STL to FBX converter — a printed part into an engine
VTubeMe's STL to FBX converter writes your .stl as a binary FBX for Unity, Unreal, Maya and 3ds Max. The mesh is carried unchanged; there is no colour or rig, because an STL has neither. Free, five conversions a day, up to 50 MB.
How do I convert an STL to FBX?
Drop the .stl on this page and download the .fbx it gives back.
- 1Drop your .stl into the box above, binary or ASCII, up to 50 MB; sign in when prompted.
- 2The file is opened in Blender on our server and written as a binary FBX 7.4. Vertices stay shared and the coordinates are not scaled.
- 3Download the .fbx and import it into your engine or DCC tool. Assign a material there — none came with the STL.
- Accepts:
- one .stl, binary or ASCII, up to 50 MB.
- Returns:
- one binary FBX, a single mesh with no material and no skeleton.
- Costs:
- nothing, and no credits — an account, though: five conversions per account per rolling 24 hours, shared across all the free format pairs. Conversions that fail are not counted.
- Measured:
- 8,696 vertices and 16,867 triangles in, the same out; a 100-unit cube is 100 units in the FBX, which declares metre-sized units.
- The FBX says its units are metres and holds the STL's numbers unchanged: a part drawn as 100 mm imports 100 m across until you scale it.
- No material, UVs or rig — the STL never had them, so an engine will show it in its default grey.
What actually happens to the file
This is the road from a printable or CAD-exported part into a game engine or an animation package, which take FBX and mostly do not take STL. The geometry is re-contained, not rebuilt: our test model went in with 8,696 vertices and 16,867 triangles and came out with exactly those, in a 0.52 MB file.
What you get is deliberately bare — one mesh, no UVs, no material. Engines need UVs for textures and lightmaps, and an STL has none to give; unwrapping is a step for Blender or your DCC tool after this one.
What this conversion cannot do
Measured on real files, not assumed. Everything below is a property of the formats or of the pipeline, and knowing it beforehand is cheaper than discovering it in your 3D tool.
The numbers are kept and the unit is not guessed
An STL stores coordinates and no unit. A cube written as 100 units on a side came out 100 units on a side in the GLB, in the FBX and in the OBJ — nothing is multiplied or divided. What changes is how the target reads those numbers: glTF defines its unit as the metre, so a part modelled as 100 mm arrives as a 100-metre object, and the FBX is marked as metre-sized units with the same 100 in it. Scale by 0.001 in the program you open it in if your STL was in millimetres. The Z-up axis of the STL is turned so the model stands upright in Y-up formats.
No colour, no UVs, no rig — there were none
STL is a list of triangles and nothing else: no materials, no texture coordinates, no vertex colours, no skeleton. The result is the same surface in a container that could hold all of those, with all of them empty. Colour has to be added in a 3D tool afterwards; no converter can recover what the file never had.
Uploads stop at 50 MB
This pair takes files up to 50 MB — half of what the GLB, FBX and OBJ pairs take among themselves, because dense scans and print files cost the converter far more memory per megabyte than a game character does. For scale: a binary STL of 50 MB is about a million triangles, and we converted one of 999,698. If your file is larger, decimate it first; MeshLab and Blender both do that without changing the format.
Five conversions a day, per account
This pair is free and takes no credits, but one account gets five conversions per rolling 24 hours across all the free format pairs together — the converter is one machine and this is what keeps it answering. Each slot frees itself 24 hours after it was used; nothing expires at midnight. Conversions that fail are not counted.
Frequently asked questions
What size will the model be in Unity or Unreal?
The FBX carries the STL's numbers and declares its unit as the metre, so a 100-unit cube is read as 100 metres by anything that honours the unit, Blender included. If the STL was in millimetres, set the import scale to 0.001. We measured the file itself and Blender's re-import; we did not open it in Unity or Unreal.
Can I texture the result?
Not straight away: an STL has no UV coordinates, and neither does the FBX made from it. Unwrap the mesh in a 3D tool first. Vertex count and triangle count are untouched, so nothing stands in the way of doing that.
Binary or ASCII STL — does it matter?
Both are read. We checked a binary STL and a hand-written ASCII one; they convert the same way. ASCII writes the same triangles out as text and is several times larger, so it reaches the 50 MB limit with far fewer triangles than the million or so a binary STL holds.
Can I just look at the STL first?
Yes, and nothing is uploaded for that: the STL viewer runs in your browser. Open the STL viewer →
The other format pairs
All 30 are free, all run the same pipeline, and all say what they drop.
GLB to FBX
GLB in, FBX out — free, one file.
FBX to GLB
FBX in, GLB out — free, one file.
FBX to OBJ
FBX in, OBJ out — free, zipped with its materials.
Blender (.blend) to FBX
Blender (.blend) in, FBX out — free, one file.
STL to GLB
STL in, GLB out — free, one file.
STL to OBJ
STL in, OBJ out — free, zipped with its materials.
PLY to FBX
PLY in, FBX out — free, one file.
DAE to FBX
DAE in, FBX out — free, one file.
USDZ to FBX
USDZ in, FBX out — free, one file.
FBX to STL
FBX in, STL out — free, one file.
FBX to PLY
FBX in, PLY out — free, one file.
FBX to DAE
FBX in, DAE out — free, zipped with its textures.
FBX to USDZ
FBX in, USDZ out — free, one file.
GLB to STL
GLB in, STL out — free, one file.
OBJ to STL
OBJ in, STL out — free, one file.
Only want to look at the file? GLB viewer, FBX viewer and OBJ viewer all run on your own device — nothing is uploaded.
Is your model going into VTubing?
A scan, a print file or a CAD part is not an avatar, and no format change makes it one: a VTubing avatar needs a humanoid skeleton and a face that moves. If what you have is a rigged character in FBX or GLB, the VRM converter maps its bones onto the VRM humanoid and carries the materials over, ready for VSeeFace, Warudo and VNyan.
Open the VRM converter