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STL FILE REDUCER

Reduce STL file size online.

Make a large STL easier to share and work with. Voloomy analyzes and simplifies your model in your browser, so the model stays on your device.

Open the STL reducer

Free single-file workspace. No installation or model upload.

FROM MODEL TO DOWNLOAD

How to reduce an STL file

  1. Open and analyze

    Choose one ASCII or binary STL. Check its triangle count, bounds, open edges, and zero-area triangles before making changes.

  2. Choose a target

    Set a target file size and detail priority. Keep open-border protection enabled when you want boundary points to stay fixed.

  3. Compare and download

    Inspect the original and result from the same camera angle. Download the binary STL and, if useful, a JSON analysis report.

SIZE AND DETAIL

Why are STL files so large?

STL describes a surface using triangles. Detailed CAD exports and scans can contain many more triangles than a particular task needs. ASCII STL also stores numbers as text, which can make the file larger than a binary representation.

Voloomy exports binary STL. ASCII coordinates are rounded to Float32 when read, so conversion can change their last digits. Reducing triangles is a separate, lossy step: small curves, thin features, and surface detail can change.

CHOOSE A USEFUL TARGET

A smaller file needs a visual check

A size target is a request, not a guarantee. Detail settings and boundary protection may prevent the model from reaching it. Voloomy reports the actual output size and tells you when the target was missed.

Start with a moderate reduction, inspect important features, and try another setting if needed. Check the downloaded model in your slicer or CAD tool before production. The original file remains unchanged.

YOUR DEVICE, YOUR MODEL

Local processing, with clear limits

Model contents and geometry are processed in browser memory and are not sent to a server for analysis or reduction. Download your result before closing the tab.

The technical input limit is 25,000,000 bytes and 500,000 triangles. For phones and tablets, files up to 5 MB and 100,000 triangles are recommended. These limits are not a performance guarantee; processing depends on your device and model.

BEFORE YOU PRINT

Does reducing an STL repair it?

No. Voloomy provides edge analysis and simplification, not hole filling or full mesh repair. A closed-edge result does not establish printability. Self-intersections, wall thickness, face orientation, and manufacturing tolerances are not validated. STL does not record units, so confirm dimensions in your production software.

Try your model in the workspace

LEARN MORE

Practical STL guides

Explore measured examples, triangle reduction and file formats