3D Model Converter

Which format should you pick?

The short answer for most people: GLB if the model is going on the web, in a game engine, or into AR. STL if it is going to a 3D printer. Everything else is a special case.

Common conversions

• STLGLB

  Put a printable or CAD model on the web, in an engine, or into AR.

• GLBSTL

  Take a generated or downloaded model into a slicer for 3D printing.

• OBJGLB

  Modernise an older asset into one self-contained file.

• FBXGLB

  Move an asset out of a proprietary format into an open one.

• STLOBJ

  Open a print file in an older tool that does not read STL well.

• PLYGLB

  Bring a scan or photogrammetry result into a normal 3D pipeline.

Why a converted model looks tipped over

This catches almost everyone once. You convert an STL to GLB, open it, and the model is lying on its back at ninety degrees.

Nothing is broken. The two formats disagree about which direction is up. STL comes out of CAD and 3D printing tools, where Z points up. GLB, glTF, and essentially every game engine and web viewer treat Y as up. Converting the file without rotating the geometry hands the viewer a model that is technically correct and visually sideways.

The Rotate Z-up to Y-up option handles it, and it switches on by itself when the source is a Z-up format. If your model still looks wrong, turn it off: some STL files are already authored Y-up, and rotating those makes the problem rather than fixing it.

What a conversion cannot do

Worth knowing before you convert something important.

• Converting to STL drops colour. STL stores triangles and nothing else. This is a property of the format, not a limitation here.
• Animation and rigs do not survive. An animated FBX converted to GLB keeps the mesh in its current pose. Skeletons and clips are not carried across.
• Conversion does not repair geometry. Holes, flipped normals, and non-manifold edges come through unchanged. A broken mesh stays broken in the new format.
• Nothing gets smaller by itself. A dense mesh stays dense. Converting to GLB is not compression, though GLB is usually the smallest of these formats on disk.

Questions

Is this 3D model converter really free?

Yes. There is no account, no watermark, no file limit per day, and no paid tier for this tool. It runs entirely in your browser, so it costs us nothing per conversion.

Are my files uploaded to a server?

No. The conversion happens in your browser using your own computer's memory and graphics card. Your model never leaves your device, which also means we never see it and cannot recover it for you.

Which formats can I convert between?

You can read STL, OBJ, GLB, glTF, PLY, FBX, and 3MF. You can write STL, OBJ, GLB, glTF, and PLY. FBX and 3MF are read only, because there is no open writer for either format.

Why does my converted model look tipped onto its back?

STL and 3MF files usually come from CAD and 3D printing tools, which treat Z as the up axis. GLB, glTF, and most game engines treat Y as up. The Rotate Z-up to Y-up option corrects this, and it is switched on automatically when the source format is Z-up.

Will my colours and textures survive the conversion?

It depends on the target. GLB and glTF store materials and textures inside the file. STL stores geometry only, so colour is lost. OBJ keeps materials in a separate .mtl file, which this tool does not write, so a converted OBJ carries shape without colour. The tool warns you before a conversion that will drop materials.

What is the file size limit?

100 MB. The limit exists because parsing happens in your browser's memory and allocates several times the file size while it works. Larger files risk crashing the tab rather than failing cleanly.

Can I convert a .gltf file that has separate .bin and texture files?

Not reliably. A .gltf file references its data as separate files, and a browser tool that receives only the .gltf cannot fetch them. Use the .glb version instead, which packs everything into one file.