Compress and optimize STL files
Reduce STL triangle count and write compact binary STL for sharing, slicing, and 3D printing. The pipeline works directly on triangle geometry and shows the exact size and polygon change before download.
Capabilities
Purpose-built for STL
- Read both ASCII and binary STL, then write the compact 84 + 50-bytes-per-triangle binary representation.
- Remove degenerate and duplicate triangles before compression instead of carrying broken surface data forward.
- Weld identical positions to build useful topology for Meshopt’s quality-focused quadric simplifier.
- Choose the exact percentage of triangles to remove and compare before-and-after triangle counts.
- Protect non-standard binary STL facet colors by refusing a destructive rewrite rather than silently discarding them.
- Process everything locally in your browser — the STL file is never uploaded.
Process
How it works
- Drop one STL fileASCII and binary STL are both accepted. The optimizer reads and checks the triangle geometry on your device.
- Set polygon reductionStart at the quality-first 30% default, then increase reduction for previews or lower it for precision parts.
- Optimize and downloadGet a binary STL plus exact file-size and triangle-count comparisons before you save it.
Format safety
What stays intact — and what changes
- STL stores surface triangles only; it has no materials, textures, hierarchy, units, or animation to preserve.
- Polygon reduction is lossy. Validate tolerances and watertightness in your slicer or CAD workflow before manufacturing.
- Binary STL with per-facet color extensions is rejected because standard STL export cannot preserve those colors safely.
- A clean binary STL with 0% polygon reduction is already near the format’s minimum size and may not become smaller.
FAQ
Questions, answered
Does this support ASCII and binary STL?
Yes. Both input variants are parsed, and optimized output is written as compact binary STL.
Will polygon reduction change dimensions?
It keeps the overall surface shape but is intentionally lossy and can soften small details. Check precision parts in a slicer or CAD tool before printing.
Why can an STL stay the same size?
Binary STL uses a fixed 50 bytes per triangle plus an 84-byte header. If the input is already binary and you keep every triangle, there is little format overhead left to remove.
Are my STL files private?
Yes. Parsing, simplification, export, and download happen in your browser without uploading the model.
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