View, repair, transform, convert and create printable STL files — no sign-in, no limits. Every tool runs 100% on your device, so your files never leave your computer.
Scale, rotate, mirror, center and lay flat.
Fix holes, normals and non-manifold geometry.
Laplacian / Taubin smoothing.
Reduce triangle count and file size.
Cut big models into printable parts with connectors.
Split multi-color 3MF models into interlocking watertight parts with tolerance-fitted assembly pins for single-extruder 3D printers.
Turn a photo into a backlit lithophane.
Displace a surface with a grayscale pattern.
Generate a printable 3D QR code.
Parametric spur gears and gear sets.
Two words from two viewing angles as one printable sculpture.
Heightmap relief or 2-tone stencil from an image.
These STL tools are completely free and run entirely in your browser — no signup, no uploads, no limits. If they saved you time, a coffee helps cover hosting and keeps them free for everyone.