Avoiding wizard spell?

[artificer]

A wizard cast a fireball and a fighter use a shield or a wall to avoid being hit . The shield takes all the damage and the fighter runs completely unharmed! On DND4 that could be a magic attack roll I think. What mechanics describes that on pathfinder?

[Umbral Reaver]

Reflex save handles that. Cover can grant a bonus to the save against some things.

[blackbloodtroll]

Using a Tower shield to gain cover would help you with reflex saves.
The Shield Evasion feat allows you to do exactly what you explained.

[artificer]

How do I know when a Saving Throw completely avoid damage and when it only reduce it?

[blackbloodtroll]

The spell will state so in it's description.

[artificer]

So if a spell dont have Saving Throw in its description it means that it cant be avoided? also a raged touch attack is like a magic attack roll?

[blackbloodtroll]

Essentially, yes.

[artificer]

Thanks a lot! I do appreciate all your help!

[Adamantine Dragon]

Artificer, be aware that there are feats or class abilities that affect damage from spells like Fireball as well. Evasion comes to mind.