Reduce a 3D mesh's triangles

What it's for

A 3D scan, an AI-generated model or a high-resolution STL export can have millions of triangles: huge files that hang the slicer and are hard to edit. Reducing the mesh lowers that count while keeping the shape — great for sharing, previewing or working faster; and if the part has threads or fits, protect them with the brush and they won't move a hair. For parts with flat faces, also check the STEP (CAD) converter; and if you're after the lattice look, the voronoi generator.

FAQ

What does reducing a mesh do?

It lowers the number of triangles (polygons) in a 3D model while keeping its shape as faithful as possible. The file gets much smaller and easier to handle in slicers, viewers or 3D software.

Can I protect parts of the model?

Yes: paint the areas that must not change (a thread, a snap fit, a logo, embossed text) right on the 3D view and the reduction will leave them untouched, vertex by vertex. In Blender this would take vertex groups; here it's a brush.

Does it lose quality?

We use quadric decimation (meshoptimizer), which prioritises keeping the silhouette and important detail, and we show you the real measured deviation in millimetres after each reduction. At moderate reductions the difference is minimal; the more you reduce, the more it shows on curved areas.

Is my file uploaded?

No. Everything runs in your browser; the file is never sent to any server. There's no size limit either: it only depends on your machine.

Which formats are supported?

It reads STL, OBJ, 3MF and PLY, and you can download the result in any of those formats.