*Markdown alternate of . Lasertally is Windows desktop software that quotes laser-cut parts for fabrication shops from CAD files, then nests the won job on sheet or tube. Unrelated to "laser tally" in oil and gas.* STEP to STL # Convert STEP to STL. Turn a STEP file (.step, .stp) into an STL mesh for 3D printing, rendering or a mesh viewer, free and with no account. Choose Standard or Fine resolution. The mesh is made in your browser, so the file never leaves your computer, and it is checked against the STEP's solid before you can download it. Your file never leaves your computer: the conversion runs in your browser. ## From exact surfaces to triangles A STEP file describes a part exactly: a hole is a cylinder and a fillet is a fillet. An STL describes the same part with flat triangles, and the only question is how small they are. The converter meshes every face so that no triangle strays further than the chosen tolerance from the true surface, then writes them all to one binary STL in millimetres. ## Picking a resolution - Standard, 0.05 mm from the surface and at most 5 degrees between neighbouring facets. Right for most prints and viewers, and the smaller file. - Fine, 0.01 mm and 1 degree. For large curved parts, or a polished surface where facets would show. ## Assemblies and multi-body files A STEP file holding an assembly or several bodies is flattened: every solid ends up in the one STL, where it sat in the assembly. STL has no way to say which triangles belong to which part, so if you need the parts separately, save each one as its own STEP file first. ## How the mesh is checked The STL is read back and measured. Its volume must match the solid's to within the surface area times the tolerance, and its bounding box to within the tolerance itself. Those two measurements are all the check makes: it does not test that the mesh is closed. Credits and licences for the projects the converter is built on are on the converter page. ## Questions ### Will the STL be watertight? A closed STEP solid normally gives a closed mesh: Open CASCADE, the CAD kernel the converter uses, meshes neighbouring faces along the same points on their shared edge. The check compares the mesh's volume and size with the solid's. It does not prove the mesh is closed, and a small missing face can pass. If a closed mesh matters, run the STL through your slicer's mesh check. ### What units is the STL in? Millimetres, whatever unit the STEP file was saved in. STL carries no unit of its own, and slicers assume millimetres, so the part comes in at its real size. ### Can I get the STEP back from the STL? Not the same STEP. Converting STL to STEP gives a faceted solid of flat faces, which is exact to the mesh but not to the curved faces you started with. Keep the original STEP. ## Quoting laser-cut parts from files like these? Lasertally is Windows software for fabrication shops. It opens STEP, IGES, DXF and NC1 files, measures the pierces, cut length and bends off the geometry, and prices the part on your own rate card. Start your free month Quoting from STEP ## Keep reading All conversions Every format pair, what is checked, and the limits. STL to STEP A mesh made into a faceted solid, and why it stays faceted. SLDPRT to STL A mesh straight from a SOLIDWORKS part. © 2026 Lasertally LLC