D&D 5e Critical Hit Extra Damage Question

When I cast a spell from the Spellbook page, if it's a critical hit, the extra damage is listed for the original hit. How do I access the info from the attack roll to add in additional damage for something like the Ice Knife spell (page 19 of the Elemental Evil Player's Companion). Specifically, Ice Knife does 1d10 damage to the target, plus an additional 2d6 damage to the target and any creature within 5' of the target (if they fail their Dex save). Putting the info into the Spellbook page gets me a second damage roll on the 1d10 if it's a critical hit, but how do I access the info from the attack roll to also have the 2d6 rerolled? I've listed the 2d6 in the Spell Effects portion of the spell as "[[2d6]] cold damage", which works correctly on a regular hit, but not on a critical hit. If this has been addressed elsewhere, please point me in the right direction. I looked around, but wasn't able to find it.

I dont think the 2d6 crits. I think the crit is applied to the 1d10, THEN the 2d6 AoE takes effect.

You create a shard of ice and fling it at one creature within range. Make a ranged spell attack against the target. On a hit, the target takes 1d10 piercing damage. (I think this is the only damage that can crit because....) Hit or miss, the shard then (<-this little guy) explodes. The target and each creature within 5 feet of the point where the ice exploded must succeed on a Dexterity saving throw or take 2d6 cold damage.

Jake M. said: I dont think the 2d6 crits. I think the crit is applied to the 1d10, THEN the 2d6 AoE takes effect. This is correct. 2d6 is based on a saving throw which cannot crit.

I have a house rule in my D&D 5e face to face campaign that if a creature critically fails their save against a spell or whatnot... it is the same as a crit in effect. So a roll of a one on a save means double damage!

That's a nice house rule! **STOLEN**!!

I appreciate your interpretation of the crit rule... I really do! However, what I'm asking is for a way to make the 2d6 reroll for a critical hit. I see that the sheet finds the crit for the 1d10, and I'd love to know where to find it so I can also apply it to the 2d6 as well.

You could always add something like "plus another [[2d6]] on a crit." to the effect section. That'll always roll the crit damage, but you can of course ignore if it it doesn't apply. It's not very elegant, but it works.

Dwayne W. said: I appreciate your interpretation of the crit rule... I really do! However, what I'm asking is for a way to make the 2d6 reroll for a critical hit. I see that the sheet finds the crit for the 1d10, and I'd love to know where to find it so I can also apply it to the 2d6 as well. Damage based on saves does not crit. That is a houserule. Do you want that?

Mark said: Dwayne W. said: I appreciate your interpretation of the crit rule... I really do! However, what I'm asking is for a way to make the 2d6 reroll for a critical hit. I see that the sheet finds the crit for the 1d10, and I'd love to know where to find it so I can also apply it to the 2d6 as well. Damage based on saves does not crit. That is a houserule. Do you want that? I don't recall seeing a rule that says "damage based on saves does not crit", and would be interested to know where this is written. Nevertheless, yes, I'd still like to know how to make this work in roll20.

Players handbook page 194 discusses how to crit. That entails rolling a 20 on an attack roll. Saving throws are not an attack roll and therefore do not crit. No mention of critting under the spells chapter. You'll have to do it manually like Garreth suggested.

Yes, I like Garreth's solution as it's certainly better than rolling the extra dice on the side. I was still hoping to be able to access the info for the attack roll, but if it's not available, then Garreth's solution is the most eloquent. Continuing on with the side discussion on crit rules, the section on page 196 says, "If the attack involves other damage dice, such as from the rogue's Sneak Attack feature, you roll those dice twice as well." I happen to view damage dice like the fighters Superiority Dice and all damage dice rolled as part of the casting of a spell attack (i.e. Ice Knife) as "other damage dice". This is the first time I've encountered anyone that has suggested that they're not. I see nothing in the rules that says something like, "this doesn't apply if there's a saving throw involved". So, I'm curious about what makes them either "not involved in the attack" or "not damage dice". For sake of clarity, I'm not interested in debating the point, I'm just curious about your perspective.

Superiority dice and sneak attack dice are rolled again, that's correct. Saves not critting is not my perspective. You can ask on Reddit, giantitp, or any forum of your choice. Spells based on saves do not crit as they have no attack roll. Secondary saves follow the same rules. Here is a tweet from Crawford about it as well (In regards to poisoned weapons). <a href="https://twitter.com/JeremyECrawford/status/5366834" rel="nofollow">https://twitter.com/JeremyECrawford/status/5366834</a>...

Interesting. Thank you. :-)