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Polyforge

Free · Browser-side · No sign-up

Convert STP to GLTF Online

Convert STEP (Standard for the Exchange of Product Data) files to GL Transmission Format (glTF), entirely in your browser. No upload, no sign-up. Your files never leave your device.

No sign-up required 100% client-side Up to 100 MB
STPGLTF

Drop your STP file here

or click to browse from your computer (up to 100 MB)

Bracket 3D model preview
Try with a sample modelBracketBracket by Polyforge · CC0 1.0 Universal

CAD bracket assembly — typical STEP engineering model for format conversion testing.

$ inspectable scene graph

STEP's parametric data becomes a readable JSON scene description, making it easy to debug and modify asset pipelines.

$ separate asset files

glTF stores geometry buffers and textures as individual files, enabling partial updates and efficient caching in web applications.

$ pbr material mapping

STEP color and surface properties are mapped to glTF's metallic-roughness PBR model for physically accurate rendering.

── STP → GLTF ──

How to Convert STP to GLTF

Convert your CAD STEP file to an inspectable, web-friendly glTF asset.

01

Upload STP

Drag and drop or select your .stp file. STEP stores precise CAD geometry as boundary representation data defined by ISO 10303.

02

Processing

Conversion runs entirely in your browser. B-rep surfaces are tessellated into triangle meshes and written to glTF's JSON structure with PBR materials. Your data never leaves your device.

03

Download glTF

Get your glTF file with Draco-compressed geometry. The JSON structure is easy to inspect, and assets load natively in web viewers and game engines.

$ why_convert

Why convert STEP to glTF?

STEP files store precise engineering geometry in a verbose ASCII format defined by ISO 10303. While this representation preserves exact surface mathematics needed for CAD workflows, it is impractical for real-time rendering, web applications, or content pipelines that require lightweight, GPU-friendly meshes. STEP files also lack the material metadata used by modern rendering engines, limiting their usefulness outside of engineering tools.

glTF uses a JSON manifest to describe scene hierarchies, materials, and animation data, with binary buffers holding vertex and index data. Converting STEP to glTF tessellates parametric surfaces into triangles, maps CAD surface properties to PBR metallic-roughness materials, and produces an asset that integrates into web frameworks and game engines. The separated file structure allows selective updates to textures or geometry without reprocessing the entire model.

Key advantages of glTF over STEP

Human readable JSON

The glTF manifest is plain text, easy to inspect and modify.

Real-time rendering

Tessellated meshes render at interactive frame rates on GPUs.

Draco compression

Optional mesh compression reduces file sizes substantially.

Broad engine support

Loads natively in three.js, Unity, Unreal Engine, and Blender.

Version control

JSON text plus separate binaries works well with Git and diff tools.

Open standard

ISO-ratified Khronos Group standard with extensive tooling.