About STL Mesh
Who runs this site, what the tools actually do, and the rules they follow.
Who runs this site
Casey Marlin
I build small, honest web tools: pages that do one job, state their limits, and leave your files on your machine. STL Mesh is one of those pages — a viewer and a converter for the 3D-print files that show up in a working day.
This site exists because checking or converting a 3D model should not require installing a slicer or uploading a client's design to a stranger's server. The usual options are to launch PrusaSlicer, Bambu Studio, or Cura — slow, heavy, and built for slicing, not for a thirty-second look — or to drop the file on an "online converter" that stores it on a server you have never heard of. Neither is acceptable when the file is a product still in development, or a client's work you are not allowed to share.
So these tools run in your browser tab. JavaScript parses the mesh, WebGL draws it, and export writes a new file back to your disk. There is no account and no upload. After the page has loaded you can go offline and the viewer still works.
What STL Mesh does
You can view STL, GLB, 3MF and OBJ in the browser. Drop a file on the homepage and you get a rotatable preview plus triangle count, vertex count, mesh count, and bounding-box size. Those stats exist because they explain the problems slicers actually report. A mesh with two million triangles will slice slowly and produce a huge gcode file. A part whose bounds read 0.04 units was almost certainly modeled in meters — glTF's native unit — and will print as a speck if the slicer assumes millimeters. Seeing those numbers before you open the slicer saves a wasted print.
You can also convert between those formats. Dedicated pages cover GLB to STL — the usual path from AI-generated and web models to a printable mesh — 3MF to STL, OBJ to STL, and the reverse directions STL to GLB and STL to OBJ. Conversion re-encodes the geometry locally. It does not remesh, repair holes, generate supports, or "optimize" anything. If the source is non-manifold, the STL will be too; use your slicer's repair tools for that.
The site is a viewer and a converter. It is not a slicer, a CAD program, or a mesh-repair suite. If you need layer height, infill, Boolean operations, or parametric history, use the tool built for that job. These pages exist for the gap between "I have a file" and "I am ready to print or share it."
Principles
- Local-first, verifiably. There is no upload endpoint on this site. After the page has loaded you can disconnect from the network, drop a model, rotate it, and export it. Everything still works. That is the proof that nothing leaves your device — not a privacy-policy paragraph, and not a promise you have to take on trust.
- Honest claims only.Conversion to STL drops what STL cannot store: colors, materials, textures, units, object names, and print settings. Every conversion page says so plainly. Geometry is kept triangle-for-triangle; everything else is not. If a tool here claimed to "preserve color in STL," it would be lying.
- Format support is stated, not stretched. The site opens STL (binary and ASCII), GLB/GLTF, 3MF, and OBJ. Nothing else is claimed. STEP, FBX, USDZ, 3DS, and native CAD formats are out of scope. If a file is not one of those four families, this site will not open it, and the pages will not pretend otherwise.
Contact
Questions, bug reports, and corrections go to support@stlmesh.com. The Contact page lists what to include so a report is actually useful. Please describe the file instead of attaching it — the tools never see your models, and email should not either.
Disclaimer
STL Mesh is an independent project. It is not affiliated with Autodesk, Prusa Research, Bambu Lab, Ultimaker, or any printer maker. Product names used on this site are trademarks of their owners.