Command Undead...what happens when?

[Darthslash]

Command Undead:

Command Undead

Using foul powers of necromancy, you can command undead creatures, making them into your servants.

Prerequisites: Channel negative energy class feature.

Benefit: As a standard action, you can use one of your uses of channel negative energy to enslave undead within 30 feet. Undead receive a Will save to negate the effect. The DC for this Will save is equal to 10 + 1/2 your cleric level + your Charisma modifier. Undead that fail their saves fall under your control, obeying your commands to the best of their ability, as if under the effects of control undead. Intelligent undead receive a new saving throw each day to resist your command. You can control any number of undead, so long as their total Hit Dice do not exceed your cleric level. If you use channel energy in this way, it has no other effect (it does not heal or harm nearby creatures). If an undead creature is under the control of another creature, you must make an opposed Charisma check whenever your orders conflict.

Q: What happens if an enemy uses a spell or ability that summons undead for 1 round per level, and I take control of them with Command Undead?

Do I keep control of them indefinitely like the feat says?

Or do the controlled undead disappear after there summon spell ends?

[Mysterious Stranger]

The undead still disappear when the duration of the spell ends. Command undead does not alter that it simply allows you to control them. I suppose that technically you are they are still under your control, but since they are no longer there it does not matter.

If command undead works the way you think it does all necromancers would be able to summon up permanent undead minions with low level spells.