Updated 2026-10-06
To convert STEP to SLDPRT, drop the .step or .stp file into the converter below and download a native .sldprt that opens in SOLIDWORKS as one solid body with true surfaces. If you have SOLIDWORKS, you may not need this: it opens a STEP directly and saves it as a part. This is for when someone needs the .sldprt itself and you have no SOLIDWORKS to make it. 2 solid conversions a day need no account.
2 solid-geometry conversions a day with no account. No card, no install.
On our servers. No account: deleted within 24 hours. Signed in: kept until you delete them. Never shared or used for training.
Planes stay planes and cylinders stay cylinders: a hole comes through as one face with a radius you can measure and mate to.
Unsupported geometry is refused with a message naming it, never silently degraded.
A STEP is a neutral solid: faces on exact surfaces, nothing else. A SLDPRT is a SOLIDWORKS document that can hold that solid plus a feature tree, sketches, configurations and material.
Converting fills the document with the solid and leaves the history empty, because the STEP never had one. The part opens as an imported body: planes, cylinders and freeform faces as the STEP described them, which you can measure, mate and build new features on. That is what SOLIDWORKS makes of a STEP itself. Neither route recovers the original features.
The part is saved for the current release, SOLIDWORKS 2026. For 2025 or 2024, re-save it with the older-version converter; for anything older, send the STEP, which every release imports. A STEP holding several bodies is not silently cut to one: the converter asks whether you want every body in one part, an assembly with a part per body, or only the first body. Assembly structure and colours in the STEP are not carried.
STEP (ISO 10303) is the closest thing engineering has to a universal solid format. It stores exact B-rep geometry — a hole is a cylindrical face, not a ring of facets. Fusion 360, Inventor, Onshape, SOLIDWORKS, Creo, NX, CATIA and FreeCAD all read it; .step and .stp are the same format. AP242 supersedes AP203 and AP214.
What you send when the other side has to keep modelling, quote machining, or open the shape in a different CAD system.
A SLDPRT file is a single SOLIDWORKS part: the exact solid — true planes, cylinders and splines — plus its feature history, sketches, material and custom properties. It is proprietary, so nothing else on your machine may open it. Assemblies are SLDASM files. One SLDPRT can hold several bodies, and those should stay separate when converting.
You were sent a SLDPRT, do not have SOLIDWORKS, and need the geometry in something your CAD system, slicer or mesher opens.
Keep the part open: fill it with a lattice, check it with FEA, texture a surface, or slice it into cut-ready sheets. These workspaces are in early access — create an account, then apply from inside the app.
Going the other way? Convert SLDPRT to STEP.
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