WebFaz 3D

OBJ to STL

PT

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OBJ to STL: convert for 3D printing

Open the OBJ (with the MTL and the images, if any) and download the STL for the 3D printer. Since OBJ does not state the unit, the app starts without changing the size, in millimeters, and shows the final size for you to check and adjust. All in the browser.

Demo model
Convert to STLGeometry only — for 3D printing

Size in the STL: 3,628.8 × 4,366.5 × 3,332.4 mm — too large for most printers: check the unit.

How to do it, step by step

  1. Open or drag the .obj file (and, if any, the .mtl and the images).
  2. Check the “Size in the STL” and choose the correct unit.
  3. Click Convert and download.

See where to click, with an image of the tool →

When this is useful

Print a model made in a modeling program

OBJ is common in the output of those programs.

Print a scan exported as OBJ

If the scan is in meters, choose Meters so the STL comes out in millimeters.

Tips for a good result

  • For OBJ, the app does not know the unit and starts in millimeters: if the size looks wrong, change it.
  • The .mtl and the textures only serve to view the model here: the STL does not carry them.

What this tool does not do

  • STL stores no colors or textures: only the shape. Colors from a scan are left out.
  • The app does not repair the model: it does not close holes, does not check whether the mesh is closed and does not trim parts. Scans usually have flaws, and the slicer (or a mesh editing program) may need to fix them.
  • The STL file does not store the unit. The app writes in millimeters, which is what most slicers expect, and shows the final size before downloading: check that it matches the real object.
  • Files of up to 400 MB. Everything is done in the browser, without sending the model.
  • The app converts and shows the model: it does not edit the mesh or the textures.

Frequently asked questions

Do I need the MTL file?
Not to convert. It serves only to see the colors in the viewer.

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Text written by Marcelo Amantino · updated October 18, 2026 · who we are