How much damage can the targets of Sculpt Spell still take? [duplicate]

Question

Recently, I had to make a ruling that did not completely sit with me. The party's Evocation Wizard tried to cast a fireball on top of the party and claimed that due to their Sculpt Spells ability, nobody in the party took any damage.

I looked up the definition from the rulebook which states this:

Beginning at 2nd Level, you can create pockets of relative safety within the effects of your Evocation Spells. When you cast an Evocation spell that affects other creatures that you can see, you can choose a number of them equal to 1 + the spell’s level. The chosen creatures automatically succeed on their Saving Throws against the spell, and they take no damage if they would normally take half damage on a successful save.

I interpreted this as simply stating, sculpt spells means creatures he chose, at MOST take half-damage (due to automatically succeeding saving throw) and IF they actually succeed on their saving throws, they will take NO damage.

I felt like otherwise Evocation wizards will have absolutely no qualm in nuking their parties to take out enemies co-located with them with no penalty and with no limited resource. However the player who's wizard it is obviously counter-argued my approach.

Is there some official guidance somewhere I missed on this issue?

Answer 1

Evocation wizards can safely nuke their parties

This is a key feature of the School of Evocation wizard subclass. They still need to expend spell slots, and the other "price" they pay is not having access to the class features of other schools, such as the School of Divination subclass' Portent feature. In other words, it's their cool thing that they can do, and they are foregoing other cool things to do this cool thing.

The Sculpt Spell feature says, as you have quoted:

The chosen creatures automatically succeed on their saving throws against the spell, and they take no damage if they would normally take half on a successful save.

This part of the quote sees that they take no damage at all from, say, fireball. They clearly pass their saves, as it says they do, but the potentially ambiguous part is where it says "they take no damage if they would normally take half on a successful save".

What this is referring to is that not all spells have damage on a successful save, so for spells like earth tremor, which deals no damage on a successful save, the "no damage" clause is irrelevant, as they wouldn't take damage anyway.

Answer 2

Sculpt spells makes affected creatures immune to the spell's effects that require a saving throw

As you quoted in your question, Sculpt Spells says (emphasis mine):

Beginning at 2nd Level, you can create pockets of relative safety within the Effects of your Evocation Spells. When you cast an Evocation spell that affects other creatures that you can see, you can choose a number of them equal to 1 + the spell’s level. The chosen creatures automatically succeed on their Saving Throws against the spell, and they take no damage if they would normally take half damage on a successful save.

So, for example with a fireball, a 3rd level (could be cast with a higher level slot to have greater sculpting potential) evocation spell, the Wizard could choose up to 4 (or more with higher slot) creatures that would automatically succeed on their saving throw, meaning that they would normally take half damage. But, since the Wizard is using Sculpt Spells, the chosen creatures take 0 damage.

Relevant text from fireball, showing the save details:

A target takes 8d6 fire damage on a failed save, or half as much damage on a successful one.

Sculpt Spells is pretty much the only thing that evocation wizards get. They're committing themselves to AoE damaging spells for their subclass.