Difference between Heighten and Arcane Augmentation?

[Charltonsexton]

I'm sorry if this has been posted before, but Google can't give me a clear answer. What is the difference between Heighten and Arcane Augmentation? They both raise the level of the spell, thus raising DC, right? Is augmentation free heightening for spells of a certain level?

[kuro_zero]

Heighten spell raises a spell to the highest level spell you are able to cast for purposes of DC only - any and all variables within the spell remain unchanged.

A spell cast under Arcane Augmentation does nothing for a spell DC, but raises the effective caster level of said spell and any variables within the spell that is affected by it (duration, damage, etc).

Spell DC is calculated as 10 Base + Level of spell + Spell Casting Ability Mod + Feats, equipment, enhancements, etc. The caster level does not affect the DC at all.

Arcane Augmentation does assist with Spell Penetration checks, as that is calculated as 1d20 + Caster Level + Feats, equipment, enhancments, etc.

[Enoach]

Agree with kuro_zero

Heighten effects spell calculations where SPELL LEVEL is a variable - This would be in the Difficulty Check

Arcane Augmentation effects spell calculations where CASTER LEVEL is a variable - This would be in Spell Penetration and Damage calculation