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Local converter

OBJ to STL Converter

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

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

Private browser conversion

Files are converted locally in your browser.

1Upload2Convert3Download

Browser-local workflow

How this tool works

  1. Step 1

    OBJ

    Choose a OBJ file from this device.

  2. Step 2

    Browser-local conversion

    The supported geometry is converted in this browser.

  3. Step 3

    STL

    Download the STL result when conversion is complete.

Preserved

  • Geometry

Lost

  • Materials
  • Textures
  • Scene hierarchy

Direct answer

What is preserved when converting OBJ to STL?

This converter processes the OBJ file locally in your browser and downloads the converted STL file. Geometry is retained by the current loader and writer. Materials, textures, and scene hierarchy are not included in the downloaded file.

Before you convert

OBJ to STL 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 OBJ to STL
DataResultWhat this implementation does
GeometryPreservedThe current exporter writes a binary triangle mesh.
MaterialsNot exportedThe uploader accepts one OBJ file, so a companion .mtl file is not read.
TexturesNot exportedThe uploader accepts one OBJ file, so images referenced by a companion .mtl file are not read.
Vertex colorsNot in sourceOBJ does not define vertex colors to carry into STL.
AnimationNot in sourceOBJ does not define animation to carry into STL.
Scene hierarchyNot exportedSTL output from this tool does not store scene hierarchy.
Units and scaleNot in sourceOBJ does not define units and scale to carry into STL.

Verify after export

  • Confirm scale and units when opening the STL file in the destination application.
  • Compare material colors and textures with the browser preview before using the result in production.

Why choose this OBJ to STL converter

Local OBJ decoding

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

OBJ to STL data report

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

STL output checks

Materials is lost; review the implementation detail and verify the downloaded file in your destination tool.

Preview before export

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

How to convert OBJ to STL online

  1. 01

    Upload your OBJ file

    Drag and drop the file into the converter, or click Upload. OBJ inputs up to 10 MB are processed locally.

  2. 02

    Convert to STL

    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 STL file

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

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

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

Frequently asked questions

Is my OBJ model file uploaded to a server?

The selected OBJ 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 OBJ to STL?

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

Is the OBJ to STL 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?

OBJ inputs up to 10 MB are accepted. The format-specific limit keeps browser-local parsing bounded; actual processing also depends on available memory, model complexity, and device performance.

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.

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.

Related converters

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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