STEP to STL converter
Turn supported STEP surfaces into a STL mesh locally in your browser. Choose tessellation quality and output coordinates in millimetres or metres; keep the precise CAD original.
What transfers and what you lose
- Self-contained ISO-10303-21 STEP/STP up to 5 MiB and 100,000 entity records. External document references are rejected. The isolated CAD worker has a 45-second time limit and 256 MiB WebAssembly memory cap.
- Output is limited to 200,000 vertices, 200,000 triangles, 2,000 meshes and 50 MiB. Choose Draft for a lighter tessellation; Fine can add triangles and may exceed the limit.
- Tessellation approximates CAD surfaces with triangles. Parametric history, constraints, exact surfaces, original colours, materials, textures and assembly hierarchy are not retained. Placed geometry is exported in the selected coordinate unit.
- STL and OBJ do not encode a standard physical unit. Select millimetres or metres, then use the same unit in the receiving application and check a known dimension. Conversion is not mesh repair or a printability certification.
- The local engine is Open CASCADE through occt-import-js. Engine licences, corresponding source archives and the reproducible memory-cap patch are linked in the tool.
Recommended workflow
- Choose a STEP file. Select a supported self-contained STEP or STP, or use the original synthetic box sample.
- Choose quality and units. Select tessellation quality and the numeric coordinate unit for the output. Run the bounded local worker.
- Inspect and download. Review mesh counts and numeric bounds, download the result and check it in the intended application.
Frequently asked questions
Is this a working STEP to STL converter?
Yes. The local CAD engine tessellates supported STEP surfaces and exports an actual mesh. Some CAD entities may not tessellate; failed or oversized outputs are rejected.
What are the limits and losses?
Self-contained ISO-10303-21 STEP/STP up to 5 MiB and 100,000 entity records. External document references are rejected. The isolated CAD worker has a 45-second time limit and 256 MiB WebAssembly memory cap. Output is limited to 200,000 vertices, 200,000 triangles, 2,000 meshes and 50 MiB. Choose Draft for a lighter tessellation; Fine can add triangles and may exceed the limit. Tessellation approximates CAD surfaces with triangles. Parametric history, constraints, exact surfaces, original colours, materials, textures and assembly hierarchy are not retained. Placed geometry is exported in the selected coordinate unit. STL and OBJ do not encode a standard physical unit. Select millimetres or metres, then use the same unit in the receiving application and check a known dimension. Conversion is not mesh repair or a printability certification. The local engine is Open CASCADE through occt-import-js. Engine licences, corresponding source archives and the reproducible memory-cap patch are linked in the tool.
Does this preserve editable CAD?
No. The result is a polygon mesh. Keep the STEP original for exact surfaces, engineering dimensions and further CAD editing.
Related conversions
This converter is free to use. Check the downloaded file in its destination application. Use the 3D File Format Converter Guide to plan the handoff, or discuss a production brief with XO3D.