Would anyone here be kind enough to change an stl file to a step file for me? I’ve read somewhere that it’s possible, but not on iOS :slightly_frowning_face:

Thanks in advance


Hi, send it to and we’ll convert it for you :slight_smile:

Thats awesome that you guys can do that. I have a bunch of stl files that need converting too. When do you think we will be able to import stl files into shapr?

Hi, we don’t have an ETA for it, it’s a really complicated procedure and often gives unusable results. I used FreeCAD to convert for Rob, because he didn’t have his laptop with him that time and it was urgent. Freecad is - as its name implies - free for anyone to download. I’m sorry if I gave the wrong impression, we generally don’t have the capacity to take on requests such as this, it’s better for everyone if we use that time to implement new features / fix bugs :slight_smile: hope you understand

Hey Tamas, ive tried using Freecad myself to convert stl - step, however without any luck, following this guide to the teeth.

I’m assuming this is also the way you’re doing it, or do you have some other way to go about it?


So, actually we don’t support STL import. At some point we will, however, currently we don’t. Every attempt to convert STL to shapr, is a hack and won’t give quality results. Here is why: Explanation of export/import formats supported by Shapr3D

I am starting to get a little obsessed with the idea of high quality STL to NURBs.

Are you aware of any GAN (Generative Adversarial Nets) project that are attempting to have a machine redraw an STL from scratch and can produce fairly high quality results. I am having a very hard time resisting the urge to work on that. I HOPE it is a thing already. I’ve not found anything yet but with all the work in that space someone must be working on it already.

Found this which may be a nice idea for detecting error in the training: GitHub - TimothyStiles/meshdiff: A command line tool to visually diff 3D meshes. Here are some almost related projects GitHub - nashory/gans-awesome-applications: Curated list of awesome GAN applications and demo

And this is The History of 3D Scan Based Reverse Engineering – Why All the Focus on NURBS? –

It’s a very well researched topic, with lots of public and proprietary algorithms. There are two big classes of algorithms:

  1. Creating b-rep from a mesh that was created from a b-rep by a cad system (this works reasonably well)
  2. Creating b-re from scanned data (this doesn’t work very well)

If you are interested in the topic I can share a few references.

I don’t want to clog the channel but I would be very open to some highlighted references to learn more about the topic.


For tessellated mesh conversion this is a great article: Polygonal Mesh to B-Rep Solid Conversion: Algorithm Details and C++ Code Samples / Habr The same author has a more detailed white paper, too.

For scanned objects I’m not a big fan of NURBS based reconstruction since the result is not more editable or precise, just smooth. There are commercial tools that capable of precise b-rep reconstruction, like Geomagic Studio, but still not automatic. This paper from Tamas Varady and his colleagues explains the basics of it, and essentially every reverse engineering system uses this method. Algorithms for reverse engineering boundary representation models - ScienceDirect