I am confused about spring attack and whirlwind, which are in the same feat chain/tree.
Combat expertise > Dodge > Mobility > Spring Attack > Whirlwind
Spring Attack
Benefit: As a full-round action, you can move up to your speed and make a single melee attack without provoking any attacks of opportunity from the target of your attack. You can move both before and after the attack, but you must move at least 10 feet before the attack and the total distance that you move cannot be greater than your speed. You cannot use this ability to attack a foe that is adjacent to you at the start of your turn.
Whirlwind
Benefit: When you use the full-attack action, you can give up your regular attacks and instead make one melee attack at your highest base attack bonus against each opponent within reach. You must make a separate attack roll against each opponent.
Since they are part of the same feat chain it's normal to assume that the feats are meant to work together in some way. But when you get to the two best in the series, it's like they won't work together. I'm pretty sure my understanding is correct in this because spring attack allows a single attack to be made, and whirlwind you make an attack against every enemy within reach.
I would so very much like to walk up to (or even into) a group of enemies, make an attack against all of them, and then move safely out of normal melee range. But I just don't think the feats work together that way? The only way I can see them legally working together is if there's only a single enemy, which spring attack alone would take care of.
Best Answer
The two feats can't be used together
Because the benefit of the feat Spring Attack gives the creature a new and special full-round action it can employ, the typical creature just can't combine the Spring Attack feat's benefit with the full-round action full attack that's necessary for realizing the benefit of the feat Whirlwind Attack.
It is one of the game's earliest and cruelest jokes to have the feat Spring Attack (and the feat Combat Expertise!) as part of the prerequisite for the feat Whirlwind Attack, and a very good example of Ivory Tower Game Design, where the author leaves the player in the dark about, in this case, this combination of feats being valuable only to the rarest of characters in the rarest of circumstances.