Onshape and Inventor are different programs that save files in different formats

No, an Onshape file is not the same as an Inventor file. They are created by different companies using different software, and they save in incompatible formats. Onshape uses the .part and .assembly file types, while Inventor uses .ipt (part) and .iam (assembly) formats. You cannot open an Onshape file directly in Inventor, or vice versa, without converting it first.

The two programs also work in fundamentally different ways. Inventor is desktop software you install on your computer — it runs locally and stores files on your machine or a network drive. Onshape is cloud-based, meaning it runs in your web browser and stores everything on Autodesk's servers. This difference affects not just the file format, but how the programs handle design history, collaboration, and file management.

Key Takeaways

  • Onshape files (.part, .assembly) cannot be opened directly in Inventor, which uses .ipt and .iam formats instead.
  • Inventor is desktop software that runs locally on your computer, while Onshape is cloud-based and runs in a web browser.
  • You can convert between the two formats by exporting to a neutral format like STEP or IGES, though some design details may be lost.
  • The two programs store design history differently, so even converted files may not preserve all the original editing steps.
  • If you need to work with both programs regularly, exporting to STEP format is the most reliable way to share geometry between them.

What happens when you try to open one file in the other program

If you attempt to open an Onshape .part file in Inventor, the program will not recognize it. Inventor will either show an error message or simply refuse to open the file. The same happens in reverse — Inventor's .ipt files will not open in Onshape. Neither program has a built-in translator for the other's native format.

This is not a limitation of either software. It is a deliberate design choice. Autodesk (which owns both programs) keeps the formats separate because they store information differently. Inventor's .ipt format includes parametric history — a record of every sketch, constraint, and feature you created in order. Onshape's .part format also includes history, but it is structured differently because Onshape's cloud architecture works differently than Inventor's local storage.

How to convert files between Onshape and Inventor

The standard way to move geometry between the two programs is to export to a neutral format. Both Onshape and Inventor support STEP (.step or .stp) and IGES (.iges or .igs) formats. These are industry-standard formats that most CAD programs can read. To convert an Onshape file to Inventor, export it as STEP from Onshape, then open that STEP file in Inventor.

When you export to STEP, you get the final geometry — the shape of the part — but you lose the design history. In Inventor, this means you will see a solid model, but you will not see the original sketches or features that created it. You cannot edit the history or go back and change a sketch the way you could in the original file. For simple parts where you only need the shape, this is usually fine. For complex assemblies or parts you plan to modify heavily, the loss of history can be a real problem.

Onshape also allows export to Inventor's native .ipt format directly, though this is less reliable than STEP. If Onshape offers a direct export option in your version, try that first — it may preserve more information than STEP. Check Onshape's export menu under File or the three-dot menu in the document.

Why the two programs handle files so differently

Inventor was designed in the 1990s as desktop CAD software. It stores everything locally on your computer or a network server. When you save an Inventor file, it writes all the design history, sketches, and features into a single .ipt or .iam file on your hard drive. This approach works well for individual designers or small teams on the same network, but it makes real-time collaboration difficult.

Onshape was built from the ground up as cloud software, launched in 2012. Because it runs in the browser and stores files on Autodesk's servers, multiple people can edit the same file at the same time, and changes sync instantly. The file format reflects this architecture — it is optimized for cloud storage and simultaneous editing, not for local file management. This is why Onshape files cannot simply be converted to Inventor format without losing information.

When you might need to convert between the two

You may need to convert files if you work with people or companies that use different software. A supplier might send you an Inventor file, but your team uses Onshape. Or you might be learning Onshape but need to open a file created in Inventor. In these cases, STEP export is your most reliable option.

Another scenario is when you need to use a specific tool or library that only exists in one program. Some companies have extensive part libraries in Inventor format. If you need those parts in Onshape, you would export them as STEP and rebuild them as Onshape parts, or import the STEP geometry and create new Onshape features around it.

What information gets lost in conversion

When you export to STEP, you lose parametric history. This means sketches, constraints, and the order of features disappear. You are left with a "dumb" solid — it has the right shape, but it is not editable the way the original was. If the original part had a hole that was 10 millimeters in diameter, and you export to STEP, that hole will be 10 millimeters in the STEP file, but there is no parameter you can change to make it 12 millimeters. You would have to recreate the hole from scratch.

Some information about materials, colors, and custom properties may also be lost, depending on what the STEP format supports. Assembly relationships — how parts fit together — are sometimes preserved in STEP, but not always perfectly. Complex constraints or motion relationships in assemblies often do not survive the conversion.

Choosing between Onshape and Inventor for your work

If you are starting a new project and have a choice, consider what matters most to your workflow. Inventor is better if you work alone or in a small team on the same network, if you need access to specialized libraries, or if your company has invested heavily in Inventor training and templates. Onshape is better if you need real-time collaboration, if you work across different locations, or if you want to avoid installing and maintaining software on your computer.

If you need to work with both, plan for conversion. Keep your primary design work in one program and use STEP export to share with people using the other. Do not expect to move files back and forth frequently — each conversion loses information, and rebuilding history is time-consuming.

Frequently Asked Questions

Can I import an Inventor file directly into Onshape?

Onshape can import STEP, IGES, and some other neutral formats, but not Inventor's native .ipt or .iam files. Export your Inventor file to STEP first, then import the STEP file into Onshape. The geometry will come through, but the design history will not.

Will I lose my design history if I convert to STEP?

Yes. STEP format stores only the final shape, not the sketches, features, or constraints that created it. Once imported, you will see a solid model but cannot edit the original design steps. You would need to recreate features if you want to modify the design.

Is there a way to keep design history when converting?

Not between Onshape and Inventor. The two programs structure history differently because of how they work — Inventor stores it locally, Onshape stores it in the cloud. No conversion format bridges this gap. Your best option is to keep the original file in its native program and use STEP for sharing geometry only.

Can I use Onshape files if my company only has Inventor licenses?

You can view Onshape files in a web browser without a license, but to edit them you need an Onshape account. If your company only has Inventor, you can export Onshape files to STEP and open them in Inventor, though you will lose the design history and will not be able to edit parametrically.

What is the best format to use if I need to share files with multiple CAD programs?

STEP is the most widely supported neutral format. It preserves geometry well and works with nearly every CAD program. IGES is another option, though it is older and sometimes produces less reliable results. For maximum compatibility, STEP is your safest choice.