[Closed] Why it didn't run?

Works for me. Though your code structure could be optimized. It doesn’t make sense to put a function within the on button pressed event, as you can only call it in the scope of the on button pressed event.

 rollout selectnomat "UnmaterialsObj"
 (
    button click1 "check"
 
 fn selectUnMaterialObj =
 ( 
  clearSelection()
  num=0
  for obj in geometry where obj.material==undefined do (num+=1;selectMore obj)
  pushPrompt (num as string+" objects have no material")
 )
 
    on click1 pressed do
    (
     selectUnMaterialObj()
    )
 )
 createdialog selectnomat
    

If were on about that i would cut it down even further

rollout selectnomat "UnmaterialsObj"
  (
  	button click1 "Check"
  	on click1 pressed do
  	(
  		select (for obj in geometry where obj.material == undefined collect obj)
  		pushPrompt ((getCurrentSelection()).count string+" objects have no material")
  	)
  )
  createdialog selectnomat

first collect all then select all at once (quicker/less UI flickering?) and remove the stupid counting. And not a seperate function as zortech mentioned.

Oh“`Great!
Thank you “zortech” and “decapitator”.:applause:
I have solved my problem by you!!