Are my files uploaded to a server?

No. This conversion runs inside your browser using your own device’s processing power, and the file is not uploaded. Once a tool has been used once (video, text recognition and background removal download their engine from this site the first time), it keeps working when your connection drops.

Why is my model grey after converting?

Its colours were in files you did not add. OBJ keeps materials in a .mtl file and the images it names in separate .jpg or .png files. Press Add more files and include them, then convert again — the shapes were always right, only the surface was missing.

Can it write FBX, or Collada, or 3MF?

No, and the picker will not offer them. Those three can be read but not written, because no browser-side writer for them exists that would produce a file your 3D program could trust. Rather than hand you something that half works, the tool only offers what it can finish: GLB, glTF, OBJ, STL, PLY and USDZ.

Do animations survive?

To GLB and glTF, yes — the clips are carried across intact. To USDZ, animation that moves whole parts is kept, but bone and blend-shape animation is not. To OBJ, STL and PLY, no, because those formats have nowhere to put them. You are told which it will be before you download.

Which format should I pick?

GLB for the web, for AR and for sending one self-contained file to somebody. STL for 3D printing. OBJ when another program needs something old and widely supported. USDZ for Quick Look on an iPhone or iPad. glTF when you want the same thing as GLB but as readable text you can inspect or edit.

How large a model can it handle?

The limit is the memory your browser can give one tab, not the format, so a phone manages less than a laptop. Above about 120 MB the page warns that the conversion needs plenty of free memory, and a model too dense to open is reported as exactly that rather than failing silently.

Convert a 3D model

Runs on your device · Your file never leaves your device.

Drop a model and choose what to turn it into. Eleven formats can be read — GLB, glTF, OBJ, STL, PLY, FBX, Collada (DAE), 3MF, AMF, VRML and USDZ — and six can be written: GLB, glTF, OBJ, STL, PLY and USDZ. The file is read, rebuilt and written on your own machine; nothing is sent anywhere, which matters more here than almost anywhere else on this site, because a 3D file is usually a client’s product, a scanned building or an unreleased design.

If your model came with companion files, add them in the same go. An OBJ keeps its colours in a separate .mtl file which in turn points at texture images; a .gltf keeps its geometry in a .bin beside it. Add all of them together and the result is complete. Leave out an OBJ’s .mtl or images and you get correct shapes in plain grey; a .gltf without its .bin cannot be read at all, and the page names the missing file.

What each format can hold is not the same, and the tool says so before you download rather than after. STL stores shape and nothing else, so colour and animation cannot travel with it — that is the format doing its job, since STL exists for 3D printers that only need the shape. PLY carries colour per point rather than as an image. OBJ holds one still shape, with its materials in an .mtl file beside it. GLB and glTF carry animation fully; USDZ carries the movement of whole parts but not of a skeleton.

How to convert a 3D model

Drop the model — and its .mtl file and textures if it has them.
Pick the format you want out.
Press Convert.
Download the result.

Supported formats and limits

Reads: GLB, glTF, OBJ (+MTL), STL, PLY, FBX, Collada (DAE), 3MF, AMF, VRML, USDZ
Writes: GLB, glTF, OBJ, STL, PLY, USDZ
Keeps animation: GLB and glTF; USDZ keeps the movement of whole parts
Companion files: .mtl, .bin and texture images are used when you add them
Where it runs: In your browser; the model is never uploaded

Not for: Writing FBX, Collada or 3MF, and CAD formats such as STEP, IGES or SolidWorks parts — those are solid-body formats rather than meshes and need a CAD kernel, not a mesh converter.

Which formats say how big the model is

Only some 3D formats say what one unit means. GLB and glTF are in metres by definition. Collada, 3MF and AMF state their unit and the tool applies it; a 3MF that states none is read as millimetres, the format's default. OBJ, STL, PLY and VRML state nothing, and FBX records a unit that the programs writing it do not agree on, so the page shows that unit without applying it.

For these, the page shows the measured size as bare numbers and asks what one unit was meant to be. GLB, glTF and USDZ are written in metres, and so are OBJ and PLY once you choose a unit. STL is the exception: slicers read its numbers as millimetres, so an STL is written in millimetres whenever the real size is known, and for an STL the choices include A metre. An incoming STL is read as millimetres when the output is GLB, glTF or USDZ.

Which way is up

Printing formats stand a model on the Z axis: STL, 3MF and AMF. glTF and the others stand it on Y. When the two differ, the page gives the model a quarter turn so it stands upright in the new file, unless you choose to keep the axes. A PLY is left as it is unless you ask, because scanners do not agree on its up direction.

What each output format keeps

GLB and glTF keep geometry, materials, texture images and animation; a glTF written here is one file, with its data stored inside it as text. STL keeps triangles only. PLY keeps the shape with normals, texture coordinates and a colour for each point, but not texture images. An OBJ comes in a zip with an .mtl file and its texture images when the model has colours or pictures, and as a single .obj when it has neither. USDZ keeps the model, its materials and animation that moves whole parts, but not bone or blend-shape animation.

Beside the download, a line names what the chosen format left out, only when the model really had it, and lists any files the model names that you did not add.

Which file is the model, and what the counts mean

The model is the largest file you added with a model extension; a zip, .gz or .kmz is used only when no file has one. In the panel after converting, Points are the corners as held during the conversion: the readers for OBJ, FBX, STL and Collada give every triangle three corners of its own, so for those formats the points are three times the triangles, even though the written file shares them.

Frequently asked questions

Are my files uploaded to a server?: No. This conversion runs inside your browser using your own device’s processing power, and the file is not uploaded. Once a tool has been used once (video, text recognition and background removal download their engine from this site the first time), it keeps working when your connection drops.
Why is my model grey after converting?: Its colours were in files you did not add. OBJ keeps materials in a .mtl file and the images it names in separate .jpg or .png files. Press Add more files and include them, then convert again — the shapes were always right, only the surface was missing.
Can it write FBX, or Collada, or 3MF?: No, and the picker will not offer them. Those three can be read but not written, because no browser-side writer for them exists that would produce a file your 3D program could trust. Rather than hand you something that half works, the tool only offers what it can finish: GLB, glTF, OBJ, STL, PLY and USDZ.
Do animations survive?: To GLB and glTF, yes — the clips are carried across intact. To USDZ, animation that moves whole parts is kept, but bone and blend-shape animation is not. To OBJ, STL and PLY, no, because those formats have nowhere to put them. You are told which it will be before you download.
Which format should I pick?: GLB for the web, for AR and for sending one self-contained file to somebody. STL for 3D printing. OBJ when another program needs something old and widely supported. USDZ for Quick Look on an iPhone or iPad. glTF when you want the same thing as GLB but as readable text you can inspect or edit.
How large a model can it handle?: The limit is the memory your browser can give one tab, not the format, so a phone manages less than a laptop. Above about 120 MB the page warns that the conversion needs plenty of free memory, and a model too dense to open is reported as exactly that rather than failing silently.