How to convert STL to STEP using FreeCAD

Sar Dar

23 Jul, 2018 11:17 PM

This tutorial covers how to convert an STL to a STEP using FreeCAD.
Note: Since STLs are meshes, the resulting model won't be as precise as parts originally made as solids.

FreeCAD can export:
- Step
- Iges
- Scad
- Dxf
- Dwg
- Obj
- Pdf
And many others…

1. Step 1: Install FreeCAD

   To start off, make sure you have FreeCAD downloaded and installed

2. Step 2: Import STL

   Open your STL part in FreeCAD

   

   Go to "Part" workbench

   

3. Step 3: Convert from Mesh to Shape

   Now, select the imported STL part in main view or the model tree.

   

   Go to Part / Create shape from mesh...

   

   Set your mesh sewing tolerance in the pop up window

   

   FreeCAD will now create a new shape in the model tree

   
   

   

   Limitations:

   • There will be no analyzing or validating of the mesh object.
   • Analyzing and repairing of the mesh (if needed) should be done manually before conversion.
   • Appropriate tools are available in the Mesh Workbench.

   
   

   If you're looking for a fast solution to get a Step exported now would be the time to export it. However, if you want a less triangulated solid or Boolean operations performed, then follow these next steps...

4. Step 4: Simplify Shape

   So you now have a shape to work with but as you can see there's still allot of triangulated faces

   

   To simplify this part, now select the shape and go to Part / Refine shape

   

   Yet another part will be added to your model tree, now simpler!

   

5. Step 5: Convert Shape to Solid

   Now, to convert the shape to a solid that Boolean operations can be performed on...

   Select your now simplified part and go again to the Part menu, this time selecting "Convert to solid"

   

   And one more time a new solid will show up in your model tree

   

   Quick Tip: Selecting a part in the model tree and pressing space will hide that selected part. This makes it easier to see the newly made shape. Hidden parts will now appear greyed out as seen in the above picture.

6. Step 6: Export

   Select the model you want to export, in this case the fourth part in the model tree

   

   File / Export

   

   And you're done! You now have a Step file from a STL file!

   
   

   
   

7. Step 7: Resources

   STL to solid conversion:

   • https://www.freecadweb.org/wiki/Part_ShapeFromMesh
   • https://www.freecadweb.org/wiki/Part_ConvertToSolid

   
   

   Working with meshes in FreeCAD:

   • https://www.freecadweb.org/wiki/Mesh_Workbench

   
   

   Prusa LCD stand:

   • https://grabcad.com/library/3d-printer-lcd-stand-1