
[ Default ] Drop To Floor (Place selected objects on Y=0.)

[ Shift] Add/update a tag that locks the current bottom plane.

[ Alt ] Use the current component selection center as the floor reference.

[ Ctrl ] Center each selected/all top-level object to world X/Z.
Shortcut
[ Default ] Drop To Floor (Place selected objects on Y=0.)
[ Shift] Add/update a tag that locks the current bottom plane.
[ Alt ] Use the current component selection center as the floor reference.
[ Ctrl ] Center each selected/all top-level object to world X/Z.