Yes i did indeed :)

but don't realised that for one simple rectangular face in a box no need to select the "4 sides" of the hole against just click an adjacent face one!

Now that is fixed in my mind ! :)

Hi Pilou - you don't need to select any individual faces at all actually, you just select the whole object with just one click so the whole thing is selected and then run Construct > Planar. Any planar openings will get sealed up.

- Michael

Yes only one click on one face if the object is boolean unioned like the model of this thread ;)

And the "4 sides" if by hasard you want in your model just one hole face planed ;)

So many possible combinaisons