100% Client-SideWebAssembly CAD EngineZero Cloud UploadsBatch Queue • ZIP

Batch STEP to STL Converter

Convert multiple .step and .stp files in bulk with one-click ZIP export. Zero server uploads, processed 100% in your browser.

Drop .STEP or .STP files here

Single or Batch • 100% In-Browser Memory • Zero Uploads

📂 Browse CAD Files

ISO 10303Multi-File BatchMax 50 MB/file

Large CAD files (>50MB) are recommended for desktop workstations due to mobile browser memory limits.

Tessellation Parameters

Deflection Controls

Quality Preset

Output Format

📐 Deflection Tolerances(Draft: 0.5mm • Std: 0.1mm • Fine: 0.01mm)▼

Draft

0.50 mm

~46° deflection

Standard

0.10 mm

~29° deflection

Fine

0.01 mm

~11° deflection

Perform topological mesh validationAudits manifold watertightness, degenerate facets, and boundary edges.

CAD Workbench

ISO 10303 • WASM

Inspection Viewport

Orbit: DragPan: Right DragZoom: Scroll

Inspection ViewportStandby • Load a STEP or STP file to verify 3D mesh geometry

01

Privacy First

100% Client-Side Privacy

Your CAD geometry never leaves your workstation. OpenCASCADE executes entirely inside a browser-local WebAssembly sandbox.

02

3D Inspection

Model Inspection

Inspect the exact tessellated mesh buffer in 3D before exporting. Toggle wireframe rendering, coordinate axes, and reference grid.

03

Mesh Verification

Mesh Validation

Detect zero-area degenerate triangles, duplicate facets, and non-manifold edges to prevent 3D printer slicing failures.

Dedicated CAD Tools

ISO 10303 Standards

STEP to STL Converter.step

Optimized for standard .step CAD solids

STP to STL Converter.stp

Optimized for .stp abbreviated files

Batch STEP to STL.zip

Convert multiple files with 1-click ZIP

3D Print Pre-Flight FitSlicer Fit

Build volume & orientation audit

CAD Mesh RepairWatertight

Auto-heal normals & slivers

STEP to OBJ Converter.obj

Convert B-Rep boundaries to Wavefront OBJ format

Batch Conversion & ZIP Export FAQ

How does batch STEP to STL conversion work in the browser?

You can drag and drop multiple .step or .stp files (or entire CAD project folders) simultaneously. The browser Web Worker queues each file, tessellates the analytical B-Rep geometry locally into STL, and packages all output files into a single .zip archive without uploading any bytes to an external server.

Is there a limit on how many STEP files I can convert at once?

No hard limit is enforced. Because conversion runs locally in your device's browser memory via WebAssembly, you can queue dozens of parts without file size caps or queue wait times.

Can I download individual STL files or only the ZIP archive?

Both. As each file finishes conversion in the queue, an individual download link becomes immediately available, and a 'Download All as ZIP' button downloads the complete project archive in one click.

Are my proprietary CAD models kept private during batch conversion?

100% private. Files never leave your device. All OpenCASCADE parsing and polygon generation happen within your browser's local sandbox.