RIP explicitly spreading around corners. 🙏

Cool

 It doesn't say everyone within line of site or not behind cover. It says everyone in the sphere. I perhaps thought that's enough to just imply that cover doesnt matter. However I see that the new AOE definition which includes this "Sphere" designation states that only TOTAL Cover from Line of Sight of the Origin, protects from the effects of the AOE. I guess PARTIAL cover won't protect you! Looks like those paper walls in the Dojo will save you, even if they catch on fire!

i cast fire ball in a 10 ft room.die.

"I cast fireball...fireball what a lovely spell that one." -Fizzband.

Quote from BamH1 >>

 It doesn't say everyone within line of site or not behind cover. It says everyone in the sphere. I perhaps thought that's enough to just imply that cover doesnt matter. However I see that the new AOE definition which includes this "Sphere" designation states that only TOTAL Cover from Line of Sight of the Origin, protects from the effects of the AOE. I guess PARTIAL cover won't protect you! Looks like those paper walls in the Dojo will save you, even if they catch on fire!

 Yeah, and as a DM, I'm cool with that. I'd use the object damage rules and rule that the fire damage completely consumes the walls, but they offered an instant of protection. I'm a collateral damage DM: unattended objects, structures, load-bearing beams, etc. in the AOE of any damaging spell always take full damage.

so, according to the Create a Spell guidelines from the DMG 2024, Fireball is balanced as a 5th level spell?
a multiple target spell at 3rd level should do 6d6, so either Fireball is overpowered by two spell slot levels or the authors do not follow their own published guidelines

Quote from Derienn >>

so, according to the Create a Spell guidelines from the DMG 2024, Fireball is balanced as a 5th level spell?
a multiple target spell at 3rd level should do 6d6, so either Fireball is overpowered by two spell slot levels or the authors do not follow their own published guidelines

 Fireball and Lightning Bolt (2014 and 2024 versions) were always intentionally overpowered.

I DINT ASK HOW MANY CHILDREN WERE STILL IN THE ORPHANAGE I SAID I CAST FIREBALL

It says "All lines coming from the point of origin" have to be blocked for that spot to no be included in the damage. The player would have to have FULL COVER, meaning it does go around corners by default ruling of AoE and Spheres if not behind total cover.

Question, it says everyone in the 20-foot radius of the sphere needs to make a Dex saving throw, what is the number they are rolling against? Is that up to the DM because it is not listed in the spell?

All magic casters have a Spell Save DC (Difficulty Check). It is typically 8 + Proficiency + Spellcasting Stat Modifier. 

So if this spell was fast by a level 6 Wizard, and their proficiency was +3 and their Intelligence was +4, 8+3+4 would mean the spell save DC was 15. That would the the target roll (meets it beats it). Hope that helps! 

Sort of, what if the fire ball was cast by a dragon? Same thing 8+the dragons int+ the dragons proficiency?

Quote from xhaven80 >>

Sort of, what if the fire ball was cast by a dragon? Same thing 8+the dragons int+ the dragons proficiency?

 Exactly! Typically you'll find the spell save DC in the "spellcasting" description for a dragon, but it does use that same formula! So if you look at the ancient Red Dragon, it says that the spell save DC for its spellcasting (including fireball) is 23. Its proficiency bonus is +7 and its charisma bonus is +8, so add those to 8, and you get 23 as your total! Hope you have fun running those monsters in your games and that it makes more sense. :)

Plan for world domination 

step 1: go into a bar full of wizards 

step 2: buy them all drinks 

step 3: invite them all to fight a dragon 

step 4: tell them all to cast fireball on the dragon at the same time

there is no I in 'team', but there are 6 I's in 'f**k it, I don't care how big the room is, I cast Fireball'

Nah man go into bar full of Sorcerers buy them all drinks, have them meta magic to dual cast Magic missile at whatever level you want, then bonus action meta magic and do it again. With the metamagic adept you can bust out an average of 65 force damage in one turn at level 3 or 80 damage if your lucky to roll max.