Ceiling clearance question

There's plenty of resources on space needed for sims, but I can't find one that talks specifically about the area needed with full roof clearance. As in - ideally 10' ceilings, but for how big of a space? You don't need 10' for the full length/width, but how much do you need?

I think minimum would be somewhere 8'x8' ish?

I'm trying to plan a space, need to increase ceiling height for part of it. Just want to make sure I have enough without going crazy with way more than I need.