STEP to STL Converter
High-precision browser conversion for standard ISO 10303-21 .step CAD files with live 3D mesh inspection.
Drop .STEP or .STP file here, or browse
Zero server uploads • Processed locally in browser memory
Tessellation Parameters
Converting CAD Model
Initializing tessellation...
model.stl
READYReady for 3D slicing and CAD export
Model Statistics
Mesh Quality & Health
PASSTopological integrity and normal orientation verification completed.
100% Client-Side Privacy
Your CAD geometry never leaves your workstation. OpenCASCADE executes entirely inside a browser-local WebAssembly sandbox.
Model Inspection
Inspect the exact tessellated mesh buffer in 3D before exporting. Toggle wireframe rendering, coordinate axes, and reference grid.
Mesh Validation
Detect zero-area degenerate triangles, duplicate facets, and non-manifold edges to prevent 3D printer slicing failures.
Dedicated CAD Tools
ISO 10303 StandardsFrequently Asked Questions
How is StepSTLTools different from online CAD converters?↓
Most online file converters upload your confidential CAD files to remote servers. StepSTLTools executes OpenCASCADE in a local WebAssembly Web Worker on your device, ensuring complete privacy, zero file uploads, and instant 3D inspection.
Which CAD formats are supported?↓
StepSTLTools currently provides dedicated high-precision converters for STEP (.step) and STP (.stp) files to Binary and ASCII STL formats, with real-time 3D verification and topological health checks.
Can I inspect the 3D model before downloading?↓
Yes. The built-in Three.js viewer renders the exact same Float32Array triangle mesh generated by the OpenCASCADE tessellator, allowing you to visually verify curved surfaces and dimensions before exporting.