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Local converter

STL to OBJ Converter

Convert STL files to OBJ locally in your browser for faster handoff across 3D tools.

Processed locally
No signup required
Files stay on your device
Browser-local STL to OBJ conversion illustration

Private browser conversion

Files are converted locally in your browser.

1Upload2Convert3Download

Browser-local workflow

How this tool works

  1. Step 1

    STL

    Choose a STL file from this device.

  2. Step 2

    Browser-local conversion

    The supported geometry is converted in this browser.

  3. Step 3

    OBJ

    Download the OBJ result when conversion is complete.

Preserved

  • Geometry

Direct answer

What is preserved when converting STL to OBJ?

This converter processes the STL file locally in your browser and downloads the converted OBJ file. Geometry is retained by the current loader and writer.

Before you convert

STL to OBJ compatibility

These results describe Modelfy's current browser loader and exporter, not every feature allowed by the file specifications.

Data preserved, limited, or lost when converting STL to OBJ
DataResultWhat this implementation does
GeometryPreservedGeometry is retained by the current STL loader and OBJ writer.
MaterialsNot in sourceSTL does not define materials to carry into OBJ.
TexturesNot in sourceSTL does not define textures to carry into OBJ.
Vertex colorsNot in sourceSTL does not define vertex colors to carry into OBJ.
AnimationNot in sourceSTL does not define animation to carry into OBJ.
Scene hierarchyNot in sourceSTL does not define scene hierarchy to carry into OBJ.
Units and scaleNot in sourceSTL does not define units and scale to carry into OBJ.

Verify after export

  • Confirm scale and units when opening the OBJ file in the destination application.

Why choose this STL to OBJ converter

Local STL decoding

The selected STL model file is decoded and rewritten as OBJ on your device; the model file is not uploaded to Modelfy.

STL to OBJ data report

The compatibility table identifies geometry as preserved by this loader and writer.

OBJ output checks

Review the generated OBJ file in your destination tool before using it in a production workflow.

Preview before export

Inspect the browser preview before converting, then use the post-export checklist to confirm the OBJ result.

How to convert STL to OBJ online

  1. 01

    Upload your STL file

    Drag and drop the file into the converter, or click Upload. STL inputs up to 25 MB are processed locally.

  2. 02

    Convert to OBJ

    Preview the model in 3D, then click Convert. The conversion runs locally in the browser; processing time depends on model complexity and device resources.

  3. 03

    Download the OBJ file

    Your OBJ file downloads straight to your device, ready for the next tool in your pipeline.

About the STL file format

Stereolithography

STL (stereolithography) describes a model as a raw list of triangles. It carries no color, texture, or unit information — just geometry — which is exactly what slicers and 3D printers need.

Both binary and ASCII STL variants exist; binary files are far smaller and are what this tool reads and writes.

Format reference: Library of Congress STL format description

Strengths

  • Native language of 3D printing workflows
  • Simple, robust triangle soup
  • Widely supported by slicers and CAD tools

Commonly used for

  • 3D printing and slicing
  • Rapid prototyping
  • CNC and manufacturing previews

About the OBJ file format

Wavefront OBJ

The Wavefront OBJ format has been a de facto interchange standard since the 1990s. It stores vertex positions, normals, texture coordinates, and faces in plain text, with materials described in a companion .mtl file.

OBJ does not support animation or scene hierarchies, which keeps it simple and portable across many modeling, printing, and rendering tools.

Format reference: Library of Congress OBJ format description

Strengths

  • Broad support across established 3D tools
  • Simple structure that is easy to debug
  • Reliable geometry interchange

Commonly used for

  • Static model exchange between tools
  • 3D printing preparation
  • Photogrammetry and scan output

Frequently asked questions

Is my STL model file uploaded to a server?

The selected STL model file is processed by the browser and is not uploaded to Modelfy. Website code and static assets still load over the network like a normal web page.

Will I lose quality converting STL to OBJ?

Mesh geometry is preserved as closely as the OBJ format allows. The target format may triangulate geometry or drop unsupported features such as animations, materials, textures, or scene hierarchy.

Is the STL to OBJ converter free to use?

Yes. The browser viewer, converter, and local 3D text tool require no account and add no watermark. Input limits vary by format, up to 50 MB; AI model generation is a separate credit-based product.

What is the maximum file size?

STL inputs up to 25 MB are accepted. The format-specific limit keeps browser-local parsing bounded; actual processing also depends on available memory, model complexity, and device performance.

Why does my STL file have no color?

The STL format only stores triangle geometry. Colors, materials, and textures are not part of the specification, so every STL viewer assigns its own display material.

Where are the materials and textures of my OBJ file?

OBJ stores materials in a separate .mtl file with texture images alongside it. This single-file browser tool does not request those companions, so it displays supported OBJ geometry with a neutral material; review the compatibility table before conversion.

Related converters

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Convert other files to OBJ

AI 3D generation

From a single image to a production-ready 3D model

These browser tools stay free for viewing and converting files you already have. When the model does not exist yet, Modelfy generates a textured mesh from one reference image — the first one is free.

Try the AI 3D generator