Free Siemens NX File Viewer Online: View .prt via STEP, No License

Hello,

I can't open the Siemens NX file (.prt) you sent me: I don't have the software. Could you send it exported as STEP (.stp, AP214)?

From Siemens NX: File → Export → STEP (.stp). It takes about thirty seconds.

If it's easier, you can also send it as a 3D link from omniview3d.com (free): I'll open it in my browser, with nothing to install.

Thank you!

Need to view a Siemens NX (.prt) file without a license? Exported to STEP from NX, it becomes a shareable interactive 3D link. No JT2Go, no Teamcenter.

Siemens NX (formerly Unigraphics) is a mainstay CAD tool in automotive and aerospace engineering. Its native files, .prt for parts and .asm for assemblies, can't be opened without an active NX license, which is a problem the moment you need to show a model to a supplier, a client, or a colleague who doesn't run NX. The universal fix: export a STEP file from NX and open it in OmniView 3D, which turns it into an interactive 3D link in under 60 seconds, in any browser.

How to open an NX file without Siemens software

Native NX files are proprietary and tied to the licensed application. The portable route is the neutral STEP format, which every recent NX release exports. Once exported, the model opens in the browser with no CAD software on the recipient's side.

1. 1In NX, go to File → Export → STEP
2. 2Choose profile AP214 (broad compatibility) or AP242 (modern, keeps PMI)
3. 3Select the parts or assembly to export, then upload the STEP file to OmniView 3D
4. 4Copy and share the interactive link, the recipient opens it in any browser

Why STEP is the right bridge out of NX

STEP is the neutral CAD exchange format standardized as ISO 10303. Its most advanced profile, STEP AP242, carries not just the exact solid geometry but semantic PMI, tolerances, and GD&T, which matters when an NX assembly moves to a supplier running SolidWorks, CATIA, or Creo. Getting that exchange right is not a detail: a landmark NIST study put the cost of imperfect interoperability in the U.S. automotive supply chain alone at over one billion dollars a year. It is one reason the tools around STEP anchor a global 3D CAD software market valued at USD 10.38 billion in 2022 and projected to reach USD 17.34 billion by 2030.

NX viewer options compared

Field notes: exporting a clean STEP from NX

• Prefer AP242 when the receiving tool supports it, you keep PMI and the assembly tree; fall back to AP214 if an import fails
• Check units before export (templates vary between inch and millimeter); a wrong unit scale is the most common surprise on the recipient's screen
• Export the full assembly rather than flattening it, OmniView keeps the sub-assembly structure so you can use the exploded view
• For a very large assembly a STEP can grow heavy; if the geometry is only needed for visual review, converting it to GLB first keeps the web view responsive

If you also handle other CAD sources, the same STEP workflow applies to a CATIA file or a SolidWorks file, and the free STEP viewer opens the result. If your NX workflow outputs JT instead, see the JT file viewer and the JT2Go alternatives. To understand which STEP profile to send, read STEP vs IGES: which format to choose.

Automotive and aerospace: why the recipient rarely has NX

In automotive and aerospace supply chains, the prime contractor and its subcontractors often run different CAD systems, so an NX model routinely lands in front of someone with no Siemens license at all, a machinist, a quality inspector, a purchasing team, a customer. Emailing a screenshot loses the 3D; sending the .prt is useless without NX. A STEP export opened as a shareable OmniView link lets any of them inspect the part on a laptop or a tablet, measure it, and comment on it without installing anything. If the STEP is large, reducing the file before sending it keeps the exchange quick.

Security: where your NX geometry lives

OmniView 3D stores your files in Europe (AWS eu-west-1, Ireland), in line with the GDPR, and your data never leaves the EU. Models are private by default: a share link exists only if you create one, and it stays revocable at any time. Project shares can carry an expiry date, files are served through time-limited signed URLs, and access is isolated per account. Your files are never used to train AI models.

Free NX viewer: what the Starter plan includes

OmniView 3D's Starter plan is free with no time limit: up to 3 models and 100 MB of storage, with STEP files accepted up to 80 MB. For heavier assemblies, the Pro plan raises the limit to 1 GB per file and 50 models, starting at $59/month excl. tax.