Jump to content
Ultimaker Community of 3D Printing Experts

how to convert a .STL to and STEP file ?

Recommended Posts

Hi guys.

I have a Little question.

I have some normal 3D stl files at home.

But I Need to have them as step data files.

Is there an easy free way to do this ?

Is it a tricky busy to comvert from stl to step ?

Also is there an Option to simplify my stl or step files ? simpler mesh ?

Thanks a lot.

Ian :)

Edited by Guest

Share this post

Link to post
Share on other sites

+1 for FreeCAD for this, but converting STLs to STEP can sometimes be tricky. It is not always a clean and easy transition. So, heads up and good luck! :)

Another option, if you know or our like to learn some programming would be to manipulate the STLs directly in OpenSCAD. No conversion necessary. Decent for tweaking existing designs. Maybe consider this a backup if your particular STLs do not like being STEPs.

And lastly, the most deal solution would be to go back to the original author of the files and ask if they are willing to share STEPs with you. Many authors are willing but just do not think of it. Then again, many 3D models are made in software that does not do solids and so does not speak STEP. But it is worth a try and the STEPs will generally be better quality than those converted from STL.

Anyway, just a few option for you to consider. Hope it helps! :)

Share this post

Link to post
Share on other sites

Thanks guys ! :)

I tried FreeCad and it did work converting my STL to STEP.

But Little Problem... all exported STEP files are between 2 and 3 times the size of the original STL.

So STL files that were 30MB are coming out at almost 100MB STEPs.

Im a Little surprised how tricky it is to move between STL and STEP..

Ill Keep trying the few new ideas.

Thanks guys.

Have a great Weekend.

Ian :)

Share this post

Link to post
Share on other sites

Look for additional FreeCAD tutorials about converting STLs. There is a function in FreeCAD to simplify models. Learning to use that could probably reduce the file size considerable. I just do not remember the details or what it is called. ... I think it is either in the Mesh or Part workbench.

As for why it is tricky, my understanding is that STLs are just a bunch of points, lines and faces. Further, every surface is broken up in the triangles so you get a lot of triangles. They have no concept of volume, or squares, or rounded surfaces, ... or surfaces at all.

STEPs on the other hand are solid objects with volume. They know about surfaces with various geometries and curves. And so it is hard to take a collection of triangles and know that those ones over there are a cylinder, and these ones over here are a square with a hole in it and the other ones over that way are a rounded edge. These are all things that the original STEP files would have in them but that you lose when converting to STL.

It is like a digital picture. It is really just a bunch of pixels. It is hard to go from pixels back to that is a face, or even that is the face of my dog. That is what you are asking for when converting STLs to STEPs.

At least that is my understanding. Hope it helps. Good luck! :)

Share this post

Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

  • Our picks

    • Introducing Ultimaker Cura 3.6 | Beta
      Ultimaker Cura 3.6 | Beta is available. It comes with new features, bug fixes, and UX improvements. We would really like to have your feedback on it to make our stable release as good as it can be. As always, you can download the beta for free from our website, for Windows, MacOS, and Linux.
        • Like
      • 95 replies
    • Print Core CC | Red for Ruby
      Q: For some users, abrasive materials may be a new subject matter. Can you explain what it is that makes a material abrasive when you are not sure which print core to use?
      A: Materials which are hard in a solid piece (like metals, ceramics and carbon fibers) will generally also wear down the nozzle. In general one should assume...
        • Like
      • 30 replies
    • "Back To The Future" using Generative Design & Investment Casting
      Designing for light-weight parts is becoming more important, and I’m a firm believer in the need to produce lighter weight, less over-engineered parts for the future. This is for sustainability reasons because we need to be using less raw materials and, in things like transportation, it impacts the energy usage of the product during it’s service life.
        • Like
      • 12 replies

Important Information

Welcome to the Ultimaker Community of 3D printing experts. Visit the following links to read more about our Terms of Use or our Privacy Policy. Thank you!