from pcdmis v2021 and up you can try this with a quick feature.
with this you can create one auto-plane from all individual surfaces as long as they have the same height
hold shift,
mouse over one plane until it gets highlighted.
left click AND hold,
move, while holding the mouse button, to the other planes,
continue until all surfaces are highlighted (Only the planes that have the same height are marked while doing this)
when all the Planes have been highlighted, let go and an auto-plane will be created
from pcdmis v2021 and up you can try this with a quick feature.
with this you can create one auto-plane from all individual surfaces as long as they have the same height
hold shift,
mouse over one plane until it gets highlighted.
left click AND hold,
move, while holding the mouse button, to the other planes,
continue until all surfaces are highlighted (Only the planes that have the same height are marked while doing this)
when all the Planes have been highlighted, let go and an auto-plane will be created