from pathlib import Path
import FreeCAD as A,json,traceback
outdir=Path(r'C:\projects\wheel\models\70_m4_threaded')
try:
 d=A.openDocument(str(outdir/'70_M4_threaded.FCStd'))
 s=d.getObject('ThreadProfiles');p=d.getObject('Parameters')
 before=s.Geometry[0].Center
 p.set('B6','46 deg');d.recompute()
 after=s.Geometry[0].Center
 h=d.getObject('ThreadHoles');f=d.getObject('FinishedPlate')
 result={'before':[before.x,before.y],'after':[after.x,after.y],'delta_mm':(after-before).Length,'thread_valid':h.Shape.isValid(),'final_valid':f.Shape.isValid(),'final_state':f.State,'changes_saved':False}
 (outdir/'parameter_check.json').write_text(json.dumps(result,indent=2),encoding='utf-8')
except:
 (outdir/'parameter_error.txt').write_text(traceback.format_exc(),encoding='utf-8')
for name in list(A.listDocuments()): A.closeDocument(name)
Gui.getMainWindow().close()