STEP & IGES to STL
STEP and IGES files describe precise, curved CAD surfaces — not a ready-to-print mesh — so this reads the real geometry with an actual CAD engine and tessellates it into a mesh you can 3D print or view: download it as STL or OBJ. Everything happens in your browser; nothing is uploaded.
How this works — and its honest limits
STEP and IGES describe a model as exact mathematical surfaces (B-rep), not triangles — a real CAD kernel (the same open-source engine behind FreeCAD and many commercial tools) reads that geometry and tessellates it into a mesh at the detail level you choose. This runs entirely in your browser after a one-time engine download; nothing you upload leaves your device. STL and OBJ have no concept of an assembly's separate named parts, so a multi-part STEP assembly is merged into one mesh on export — the shape is faithful, the part structure isn't kept.
What's the difference between this and your other 3D model converter?
3D model converter reshuffles mesh formats that are already triangles (OBJ, FBX, STL, PLY, DAE) into glTF/GLB. STEP and IGES aren't triangles at all — they're exact curved surfaces — so converting them needs a real CAD geometry engine to compute a mesh first, which is what this tool does. Once you have an STL from here, feed it into the 3D model converter for glTF, PLY or DAE.
Why does the triangle count change with the Mesh detail setting?
A curved surface can only be approximated by flat triangles — more triangles hug the curve more closely. Draft uses a coarser tolerance for a fast, lightweight result; Fine uses a much tighter tolerance for smoother curves at the cost of a larger file and a longer wait, especially on complex models.
Will my STEP file's units come out right?
STEP files store their own unit internally, and the reader converts from that to whatever you pick in Output unit — millimetres by default. If a dimension still looks off by a factor of 10, 25.4 or similar, double-check the Output unit matches what you actually want.
My file has several parts — will they stay separate?
No — STL and OBJ don't have a concept of named assembly parts, so every part in the file is merged into a single mesh on export. The overall shape comes through correctly; only the part boundaries and any names are lost, which is a limit of the STL/OBJ formats themselves, not of the reading step.
Is anything uploaded?
No. Reading the STEP/IGES file and tessellating it into a mesh both happen entirely in your browser, using a CAD engine that downloads once (a few megabytes) and is cached after that — your file itself never leaves your device.
