Convert STEP
to Parasolid.

Updated 2026-10-06

To convert STEP to Parasolid, drop the .step or .stp file into the converter below and download an .x_t. Planes, cylinders, cones and NURBS faces are rebuilt as the same true surfaces, so the solid behaves like modelled geometry in SOLIDWORKS, Solid Edge or NX. No account is needed for up to 2 solid conversions a day. Most CAD systems can also open the STEP and export Parasolid themselves.

2 solid-geometry conversions a day with no account. No card, no install.

No account needed
Drop a STEP file.step / .stp · up to 200 MB
Several bodies

On our servers. No account: deleted within 24 hours. Signed in: kept until you delete them. Never shared or used for training.

ResultTrue surfaces

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.

ChangesSTEP → Parasolid

What changes between STEP and Parasolid

Both formats describe a solid the same way: faces lying on exact surfaces, bounded by edges on exact curves. STEP is the neutral, ISO-standard way of writing that down; a Parasolid transmit file is the way a particular modelling kernel writes it, the kernel under SOLIDWORKS, Solid Edge and NX.

So the conversion keeps the geometry and changes the dialect. A hole is still one cylindrical face with a radius you can measure and mate to, and dimensions do not move. What a STEP file can carry and a bare .x_t cannot, such as assembly structure, colours and product names, is not carried over. When the STEP holds several bodies they are written into one .x_t, and the result says how many.

Why do it at all, when those systems read STEP? Because some people, and some PDM workflows, ask for Parasolid by name, and between kernel-sharing systems it is often the more faithful hand-over.

HowThree steps
  1. Drop your .step file above — up to 200 MB without an account.
  2. Parasolid is already selected as the output.
  3. Download the .x_t. Without an account, files are deleted within 24 hours; signed in, they are kept until you delete them.
FormatsWhat you are holding

STEP file (ISO 10303) (.step / .stp)

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.

Parasolid transmit file (.x_t / .x_b)

Parasolid is the modelling kernel under SOLIDWORKS, Solid Edge and NX, and a transmit file is its exact solid geometry. Between systems that share the kernel it often survives better than a neutral format. .x_t is text, .x_b is binary; both hold the same solid.

Someone in a Siemens or SOLIDWORKS shop sent you an .x_t and nothing you have opens it.

Questions10 answered
How do I convert STP to x_t?
Drop the .stp (or .step; they are the same format) on this page, where Parasolid is already selected, and download the .x_t.
Do I get an .x_t or an .x_b?
An .x_t, the text encoding, which is what SOLIDWORKS, Solid Edge and NX users usually exchange. The binary .x_b holds the same solid at the same precision; the encoding makes no difference to the geometry.
What if the STEP has faults in it?
The converter checks the STEP you upload and says if it already had invalid faces or open shells, so a defect in the original is not blamed on the conversion. A STEP that is a set of loose surfaces rather than a closed solid may not convert to a solid at all.
Will the .x_t open in SOLIDWORKS?
Yes, as an imported solid body with no feature tree. SOLIDWORKS opens STEP just as well, so if the recipient uses SOLIDWORKS, ask whether they need Parasolid at all.
Is the STEP to Parasolid converter free?
Yes. 2 solid-geometry conversions a day with no account, of 5 in total. A free account converts 4 solid files a day and adds 25 credits. No card.
Will the Parasolid file keep exact curves and holes?
True surfaces are rebuilt, so the Parasolid result behaves like modelled geometry. 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.
Will the Parasolid file open in Fusion 360, Inventor or Onshape?
Yes. Parasolid is read directly by Fusion 360, Inventor, Onshape, SOLIDWORKS, Creo, NX and FreeCAD. It arrives as a solid body you can measure, mate and cut.
How big a file can I convert?
To a mesh format like STL: 300 MB with a free account, 200 MB without one. To STEP, Parasolid or SLDPRT: 140 MB, because rebuilding a solid takes about twice the memory of writing a mesh. Maker and Studio convert up to 830 MB and 380 MB — a large conversion on a paid plan gets the server to itself.
Is it safe to upload my STEP file?
Files travel encrypted and are processed by machine on our own servers — no third parties, no ads or trackers, no AI training.
Is my STEP file deleted after converting?
Without an account, the upload and the result are deleted within 24 hours. With an account, both stay in your files until you delete them; deleted files leave our servers within 24 hours.
Beyond convertingSame file, four workspaces

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.

Create free account See pricing

AlsoOther ways in
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Going the other way? Convert Parasolid to STEP.

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