"n" pillars that cross the floor

[mir]

Here I am.
I remember seeing him do... but I don't remember how
floor crossed by "n" pillars... how do I do in one blow only all the holes in the floor?

I remember a way ... but maybe it was another software

Thank you.
♪

 

[Tristan]

change > join (by quitting the 'multiple' option), select the floor, then all the pillars through window