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how to convert a .STL to and STEP file ?


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Posted (edited) · how to convert a .STL to and STEP file ?

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 :)

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    Posted · how to convert a .STL to and STEP file ?

    +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! :)

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    Posted · how to convert a .STL to and STEP file ?

    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 :)

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    Posted · how to convert a .STL to and STEP file ?

    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! :)

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    Posted · how to convert a .STL to and STEP file ?

    Converting mesh files to solid formats is a complex task.

    While converting files from mesh to solid you should look for accuracy, number of patches, file size and many other variables that should be taken in consideration based on the use you will give for the solid file.

    I have compiled some thought as a starting point for this research, make sure your STL/OBJ/PLY (mesh) file has a decent quality. Meshmixer/Meshlab can do a validation on the file quality.
    You will CONSIDERABLY increase your chances by having a watertight model. If the model does not have a closed mesh, you will most likely have a hard time/fail converting it.



    There are 4 ways to do it:


    1 - Using free software

    This is a valid solution for a simple shape models. Here are some tutorials available on internet:




    2 - Professional software solution

    This is probably the best solution for companies with a high conversion volume and other CAD/CAM demand. The best solutions I have found:

    3D Systems Geomagic Wrap

    Fusion 360

    Power Surfacing (SolidWorks plugin)


    3 - Hiring a professional freelancer

    Higher chance to get a decent converted file for an affordable price. Try to look for the feedback/customer review before hiring someone. I have seen professionals charging as cheap as US$25 per model/conversion. You can check on these options (there are many others):





    4 - Online conversion platform

    There are solutions with instant delivery, and other that takes some days to process the file. I found solutions varying from free online conversion to expensive prices. There are prices as low as US$1 per file. You can check on these platforms (there are others on Google):





    Have in mind that, the higher is the model complexity (shape), the harder is the model to convert.

    If trying to conver a 3D scanned model, make sure to have a closed mesh and a high density mesh definition. Don’t expect to convert a model 3D scanned using a smartphone to anything decent.


    During your Google research, you can also use the term “model surfacing”.


    Good luck!

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