Charging into buildings/multiple floors

Howdy y'all. How does charging into a unit that is on the 2nd floor of a building while you're on the 1st floor work? Is it 3" per level? do you measure the vertical distance in inches? Etc. Also, I know that monstrous creatures/vehicles are no longer allowed to move fully into buildings/ruins and that helps units like Scourges and other flyers survive by avoiding melee, how exactly do the rules work?

There isn't a 3" per level rule anymore. So you would move the actual distance required to get between levels.

For the sake of Drukhari galactic domination, that means you should make terrain with floors 6.5" apart, so dirty imperials can't climb between levels.

It looks like movement isn't all or nothing. The rules look similar to Shadow Wars and if a model is half way there, put some dice under it. "Wobbly Model"

I believe that as per RAW you are right. @Myrvn

I swear they covered it in the FAQ or possibly the quasi-FAQ for changing editions, but I can't find it now.

The FAQ was for Harlequins, they said you treat terrain like fly and measure at an angle, and it wasnt in the Official faq but the fast live stream one i believe, they said during that part that all measurements through terrain is true distance, like if the model you are charging is 3" over and 2" up you need a 4" charge.

Question #4 for Core Rules on Stepping Into A New Edition of Warhammer 40,000 - Q. What happens when an Infantry model cannot completely end its move on a floor of ruins when
attempting to scale the walls?

A. If an Infantry model is unable to complete a move
to a stable position, use the Wobbly Model Syndrome guidelines in the core rules to identify with your opponent where your model’s actual location is.

Not quite sure if posting an FAQ answer is kosher.

Yeah you can post faq's answers, basically if its public you can post it.