# STL Viewer

Free online STL viewer. Open and preview 3D models (.stl) directly in your browser — no upload, no 3D software.

> Canonical page: https://elysiatools.com/en/viewers/stl

- **Category:** 3D Models

- **Supported formats:** .stl

## Overview

This STL viewer renders stereolithography 3D models directly in your browser using WebGL. STL (.stl) is the standard format for 3D printing and rapid prototyping, representing 3D surfaces as a collection of triangular facets. Pick a sample model or choose your own .stl file to preview it in an interactive 3D viewport, with no upload.

## When to use

- You downloaded an .stl file for 3D printing and want to preview it first.
- You need a quick, private check of a model before sending it to the slicer.
- You want to inspect a CAD-exported STL on any device.

## How it works

- Select a built-in sample model or choose your own .stl file.
- The viewer loads the model with WebGL (three.js) in your browser — nothing is uploaded.
- Rotate, zoom and pan to inspect the triangulated surface.

## Use cases

- Previewing 3D print models.
- Checking CAD exports before printing.
- Inspecting scan data and mesh quality.

## Samples

- **Sample STL Model**: A STL 3D model sample for in-browser preview

## Frequently asked questions

### What is an STL file?

STL (.stl, Stereolithography) is a file format for representing 3D surfaces as a mesh of triangles. It is the de facto standard for 3D printing and rapid prototyping. STL files come in ASCII (readable text) and binary (compact) versions.

### Are my STL files uploaded?

No. Models you open from your device stay on your device and are rendered locally with WebGL. Only the public sample model is requested from the server.

### Does STL contain color or texture?

No. Standard STL files store only geometry (triangle positions and normals). Color and texture information is not included — STL is purely a surface mesh format for 3D printing and prototyping.

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