freecad macro to export selected objects into stl and open in prusa slicer. MOVED into it's own repo https://github.com/corpix/freecad-slicer

freecad-slicer-export.py

import FreeCAD, FreeCADGui, Mesh, subprocess, os, tempfile, shutil, threading

# Setup for custom slicer:
## Open python console
## Run FreeCAD.ParamGet("User parameter:BaseApp/Preferences/SlicerMacro").SetString("SlicerCommand", "custom-slicer")
## Now you should be able to get 'custom-slicer' with FreeCAD.ParamGet("User parameter:BaseApp/Preferences/SlicerMacro").GetString("SlicerCommand", "")

slicers = ["prusa-slicer", "orca-slicer"]

def get_slicer_path():
    param = FreeCAD.ParamGet("User parameter:BaseApp/Preferences/SlicerMacro")
    slicer_command = param.GetString("SlicerCommand", "")

    for command in [slicer_command] + slicers if slicer_command else slicers:
        slicer_path = shutil.which(command)
        if slicer_path:
            return slicer_path
    
    FreeCAD.Console.PrintError("No valid slicer found. Please set SlicerCommand parameter (see comments in macro file).\n")
    return None

def run_slicer(filepaths, temp_dir, slicer_path):
    try:
        subprocess.run([slicer_path] + filepaths)
    except Exception as e:
        FreeCAD.Console.PrintError(f"Failed to run slicer {slicer_path}: {e}\n")
    finally:
        try:
            shutil.rmtree(temp_dir)
        except OSError:
            pass

def main():
    slicer_path = get_slicer_path()
    if not slicer_path:
        return 
    
    selection = FreeCADGui.Selection.getSelection()
    if not selection:
        FreeCAD.Console.PrintError("No objects selected.\n")
        return

    temp_dir = tempfile.mkdtemp()
    project_name = FreeCAD.ActiveDocument.Label.replace(" ", "-")
    stl_files = []

    for obj in selection:
        body = None
        for parent in obj.InList:
            if parent.TypeId == "PartDesign::Body":
                body = parent
                break
        part_name = (body.Label if body else obj.Label).replace(" ", "-")
        
        filename = f"{project_name}_{part_name}.stl"
        path = os.path.join(temp_dir, filename)
        
        Mesh.export([obj], path)
        stl_files.append(path)
    
    threading.Thread(target=run_slicer, args=(stl_files, temp_dir, slicer_path), daemon=True).start()

main()

moved into it's own repo https://github.com/corpix/freecad-slicer