Convert STL to DXF

STL format is typically used for 3D printing, and it is not surprising that sometimes users require these simple models to be recovered back to 2D CAD format via a process often labeled as 'drafting'. Drafting essentially translates specific views or aspects of a 3D model and saves these as 2D drawings, often to DXF, DWG, or any of the proprietary 2D CAD formats used in various professional CAD tools.

Such stl to dxf conversion can be done with pretty much every modern 3D CAD modeling tool (many are listed here), but it is not limited to just professional and expensive tools and can be made using open source solutions, such as FreeCAD.

How to draft STL models to DXF format using FreeCAD

Converting STL file to a DXF file using FreeCAD involves several steps. The process includes importing the STL file, creating a 2D projection or section of the 3D model, and then exporting that 2D representation to a DXF file. Here’s how you can do it:

Step 1: Import the STL File

• Open FreeCAD
• Go to File ► Import and select your STL file to import it into FreeCAD.
• The STL will appear as a mesh in FreeCAD.

Step 2: Convert the Mesh to a Solid (optional)

• To work with the mesh more effectively in FreeCAD, you might need to convert it to a solid.
• Switch to the Part workbench. Select the mesh object in the model tree and go to Part ► Create shape from mesh...., select the mesh and click Create.
• This will create a new shape, which you can then convert to a solid by selecting it and using Part ► Convert to solid option.

Step 3: Create a 2D Projection or Section

• Switch to the Draft or TechDraw workbench, depending on whether you want a more schematic or a more precise technical drawing.
• For a simple projection (Draft workbench), select the solid and use Draft ► Shape2DView to create a 2D projection of the shape.
• For a technical drawing (TechDraw workbench), use the various tools in TechDraw to create views and sections of the solid.

Step 4: Export to DXF

• Once you have the 2D representation, select it and go to File ► Export option and choose DXF as the file format to export the selected 2D view.
• After exporting, it's a good idea to open the DXF file in another program to ensure the result