I am thinking about taking smash from air feat and it sais that it can be user against spell effects. What counts as spell effects? Do supernatural abilities also count?
Does alchemists bomb count as spell effect?
Spell effects lacking any other definition, would likely be effects created only by spells. You might get SLA to qualify.
I doubt supernatural abilities would qualify at all.
What counts as spell effects? Do supernatural abilities also count?
Spells (whether cast by a caster or generated from a spell-trigger or spell-completion items) and spell-like abilities generate spell effects.
Supernatural abilities generate supernatural effects, not spell effects.
Especially for the purposes of the feat Smash from the Air, where an attack roll is mentioned as an additional limitation. The intent here is clearly to refer to the effects generated by casting spells or using a spell-like abilities to attack with the resulting spell effect.
For example, you could deflect a Scorching Ray or an Acid Arrow. You could even deflect a Flame Bolt from a cleric with the Flame domain using this feat.
You could not block Magic Missile which makes no attack roll. You also could not block a supernatural ranged attack.
I am actually having trouble finding a good supernatural ranged attack as an example, though. All the ones that came to mind immediately (e.g. lantern archon's light rays or a yrthak's sonic lance) turned out to be Ex not Su.
Does alchemists bomb count as spell effect?
No, they are not.
Paizo's PRD for Alchemist Base Class clearly lists them as a (Su) ability, or supernatural. So, this is the example I was looking for above. You cannot block them with the feat.
Of course, I want to note that I think you probably can use the prerequisite feat, Cut from the Air to knock down an Alchemist's Bomb. It seems reasonable that it falls within the category of "weapon (or ammunition)." Looking at the RAW, I would allow a player to block an grenade like weapon with Cut from the Air, though I believe that would be enough to detonate a bomb or break an acid flask, thus suffering from the splash damage.
Thank you for your responds :)