Spellcasting and Variable DC's: balance?

[Gerrtt]

I had a little thought lately about how to mess with spellcasting a little bit. Basically, I thought that if there was a way to make it so that spell DCs were not always the same it might add some variability to the power of casting classes. Here's how it might work, and bear with me if I haven't figured out all the details, it's still a plan in motion. Allow me to compare how it is now to how I think I might like to adjust it:

1) Any given spell of a given level will be the same every time regardless of individual casts (example, a 5th level wizard with 18 int will always cast a DC 17 fireball).
2) As a result, individual castings of spells are essentiall identical and non-dynamic, resulting in putting all the chance of success or failure of a given spell on the reciever of said spell. (example, the same fireball as before, the only person who determines the success of the fireball is the group of goblins it is cast on, not the wizard him/herself).

Now, to see how I might change it:

a) Any time a caster casts a spell the caster makes a spellcasting check to determine the DC rather than using a flat rate. The formula for said check is: 1d20 + 1/2 CL(rounded down) + casting stat. mod. (example, a 5th level wizard with 18 int rolls 1d20 + 2 + 4 to determine the DC of a spell).
b) As a result, each casting of fireball becomes more dynamic, potentially ranging from very easy to resist to irresistable (just like a melee class' attack rolls). Using the same example of the fireball from before, the DC ranges from 7-27, meaning that half the time a caster will be casting below what they would using RAW, and half the time they would be casting above it.

Essentially, it means making an attack roll with spells that determines the effectiveness instead of just using a flat rate. It also means more rolling dice for casters.

Potential issues:

1) For spells that already require an attack roll and spell resistance, this means adding yet another chance for failure.

-It sure does, but it seems to me that with the ultimate power associated with some of the higher level spells, more chances to fail should make their successes all the more exciting.

2) Doesn't this give casters more to keep track of? We already have attack rolls, spell effects and their durations, and other stuff to keep track of, why should we add another?

-Honestly, I recognize this one. Casters already have the most to keep track of on their side of the GM screen. But really all it is is saying that instead of Taking 10 on your effective spellcasting roll (see RAW formula for calculating Spell DC compared to mine) you roll a dice and add the modifier. Not too bad, you just work out the modifier ahead of time, just like you do for all your other stuff.

Now, honestly, I like the spell casting classes just the way they are and see room for all types of casters using the system already in place. I also see that there are those among you who don't feel the need to play a caster that can kill anything on their own and recognize that being the most powerful character isn't a legitimate goal, and that there are those of you who feel the exact opposite. This idea isn't really about that.

This is about making a change to the spellcasting system that makes the spells themselves more dynamic, and thus more exciting. Thoughts?

[tainsouvra]

1) Any given spell of a given level will be the same every time regardless of individual casts (example, a 5th level wizard with 18 int will always cast a DC 17 fireball).

Ok, to reiterate...the result of this is from 10+[spell level]+[stat mod]. This means:
Level 5 Wizard with 18 int: DC 17
Level 10 Wizard with 18 int: DC 17
Level 15 Wizard with 18 int: DC 17

Any time a caster casts a spell the caster makes a spellcasting check to determine the DC rather than using a flat rate. The formula for said check is: 1d20 + 1/2 CL(rounded down) + casting stat. mod. (example, a 5th level wizard with 18 int rolls 1d20 + 2 + 4 to determine the DC of a spell).

To reiterate this one, the result is d20+[half character level]+[stat mod]. The average result of each will be written below:
Level 5 Wizard with 18 int: DC 16.5
Level 10 Wizard with 18 int: DC 19.5
Level 15 Wizard with 18 int: DC 21.5
You are making spellcasters more powerful. Consider this carefully.

If you do go with a variable spell DC rule, I'd just go with the published one. Instead of 10+[spell level]+[stat mod], it's d20+[spell level]+[stat mod]...at least it doesn't make spellcasters even stronger...

[Gerrtt]

Where is the published variable system? I don't think I've seen it anywhere in the books I've read of SRD (which I glanced over just before making this post to make sure I didn't miss it).

That said your input does make sense /dispite only looking at averages, and if I were to go that route I would probably change the mechanic to spell level rather than caster level.

[Ramza00]

If you do go with a variable spell DC rule, I'd just go with the published one. Instead of 10+[spell level]+[stat mod], it's d20+[spell level]+[stat mod]...at least it doesn't make spellcasters even stronger...

How about 3d6+spell level+stat mod *tongue*

[Thinker]

Spellcasters and nonspellcasters have generally the same opportunities to fail:

Barbarian Bob (BB) attacks Jackoff 1 (JO1). BB rolls a 15 versus JO1's static AC of 14 and hits. No matter what BB rolls, JO1's AC is the same.

Caster McCasterton (CM) casts Sleep on Jackoff 2, 3, and 4 (JO2, JO3, JO4). JO2 rolls a 16, JO3 rolls a 15, and JO4 rolls a 3 all versus the static DC of 15.

The only difference is that a caster's attack is static versus the defender's dynamic defense, whereas a noncaster's attack is dynamic versus the defender's static defense.

Adding more rolls with similar averages does nothing to help balance anything.

[Gerrtt]

Even still, the question wasn't necessarily about balancing the spellcasting system to melee combatants. It was about making spells dynamic in a way that didn't make it more or less powerful than what was already in place.

I can see why you might think it was about balance though, since the word balance is right there in the thread title. What that referred to was is this balanced against what is already in play. Based on what I've seen already I admit that it probably isn't and would go a different route (spell level check instead of caster level check, as per what seems to be the published rules for variable DCs that I haven't read, correct me if I'm wrong and please provide a location for them if possible).

I'm really not trying to make casters weaker, just wanted to make it so that having high DCs had more to do with stats and luck than just raw stats.

[Jasdoif]

It actually makes spellcasters more powerful. Unless the preroll save DC is 5 or more lower then the save bonus, the save is less likely to succeed.

EDIT: OK. Let's take a simple example: A caster's CL is 2, and his int modifier is +2, making the save DC d20+3. The target is has 1 level with a good save of +2 and associated modifier of +1, making the save d20+3.

Under normal rules, the save DC would be 13, so with a save bonus of +3 the target could make the save 55% of the time (roll of 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20).

Spoiler

Show

{table=head]SAVE|DC|4|5|6|7|8|9|10|11|12|13|14|15|16|17|18|19| 20|21|22|23
Nat. 1||n|n|n|n|n|n|n|n|n|n|n|n|n|n|n|n|n|n|n|n
5||Y|Y|n|n|n|n|n|n|n|n|n|n|n|n|n|n|n|n|n|n
6||Y|Y|Y|n|n|n|n|n|n|n|n|n|n|n|n|n|n|n|n|n
7||Y|Y|Y|Y|n|n|n|n|n|n|n|n|n|n|n|n|n|n|n|n
8||Y|Y|Y|Y|Y|n|n|n|n|n|n|n|n|n|n|n|n|n|n|n
9||Y|Y|Y|Y|Y|Y|n|n|n|n|n|n|n|n|n|n|n|n|n|n
10||Y|Y|Y|Y|Y|Y|Y|n|n|n|n|n|n|n|n|n|n|n|n|n
11||Y|Y|Y|Y|Y|Y|Y|Y|n|n|n|n|n|n|n|n|n|n|n|n
12||Y|Y|Y|Y|Y|Y|Y|Y|Y|n|n|n|n|n|n|n|n|n|n|n
13||Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|n|n|n|n|n|n|n|n|n|n
14||Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|n|n|n|n|n|n|n|n|n
15||Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|n|n|n|n|n|n|n|n
16||Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|n|n|n|n|n|n|n
17||Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|n|n|n|n|n|n
18||Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|n|n|n|n|n
19||Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|n|n|n|n
20||Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|n|n|n
21||Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|n|n
22||Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|n
Nat. 20||Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y[/table]

That gives him 209 chances out of 400 to succeed. Which is 52.25%. He's down 2.75% in this case.

Now, for an extreme example, suppose the target's base save in the same case is +12. Under normal rules, only a natural 1 would result in failure, making the chance to succeed 95%.

Spoiler

Show

{table=head]SAVE|DC|4|5|6|7|8|9|10|11|12|13|14|15|16|17|18|19| 20|21|22|23
Nat. 1||n|n|n|n|n|n|n|n|n|n|n|n|n|n|n|n|n|n|n|n
14||Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|n|n|n|n|n|n|n|n|n
15||Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|n|n|n|n|n|n|n|n
16||Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|n|n|n|n|n|n|n
17||Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|n|n|n|n|n|n
18||Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|n|n|n|n|n
19||Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|n|n|n|n
20||Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|n|n|n
21||Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|n|n
22||Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|n
23||Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y
24||Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y
25||Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y
26||Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y
27||Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y
28||Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y
29||Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y
30||Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y
31||Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y
Nat. 20||Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y|Y[/table]

So, 355 chances out of 400 to succeed. Which is 83.75%. Down 11.25%.

[tainsouvra]

Where is the published variable system? I don't think I've seen it anywhere in the books I've read of SRD (which I glanced over just before making this post to make sure I didn't miss it).

DMG page 36, Variant: Spell Roll. I don't know if it's in the SRD.

Edit: While you're at it, check out the downsides to this method that it mentions. In general, making spell DC's more random favors the monsters over the PC's.

[Yakk]

d20 vs d20 is different than d20 vs static.

Modifiers in d20 vs d20 have about a 30% lower impact[1] on the result than modifiers in d20 vs static.

A simple example that illustrates how modifiers have different impact is:
d20 vs 11: 50% chance to succeed.
d20 vs 21: 0% chance to succeed.
d20+0 vs d20+0: 50% chance to succeed.
d20+0 vs d20+10: 13.75% chance to succeed.

At lower scales, each +3 in d20 vs d20 has about as much impact as a +2 change in the DC of the target number of d20 vs static.


...

So what does this mean? By making spell DCs dynamic, you reduce the importance of each point of +spell power and +resist, and increase the amount of chance involved.

Footnote:
[1](Roughly 1/sqrt(2) as important, to be more exact.)

[Ramza00]

Spellcasters and nonspellcasters have generally the same opportunities to fail:

Barbarian Bob (BB) attacks Jackoff 1 (JO1). BB rolls a 15 versus JO1's static AC of 14 and hits. No matter what BB rolls, JO1's AC is the same.

Caster McCasterton (CM) casts Sleep on Jackoff 2, 3, and 4 (JO2, JO3, JO4). JO2 rolls a 16, JO3 rolls a 15, and JO4 rolls a 3 all versus the static DC of 15.

The only difference is that a caster's attack is static versus the defender's dynamic defense, whereas a noncaster's attack is dynamic versus the defender's static defense.

Adding more rolls with similar averages does nothing to help balance anything.

it adds risk to the situation thus it works as a deterent. Furthermore with your logic arcane mastery would never be taken by a dispeler/counterspeller mage, yet for some reason that feat is always taken.

[Gerrtt]

DMG page 36, Variant: Spell Roll. I don't know if it's in the SRD.

Edit: While you're at it, check out the downsides to this method that it mentions. In general, making spell DC's more random favors the monsters over the PC's.

Pardon me for sounding sardonic, but...so? Heaven forbid someone throws the monsters a bone every now and then, giving them a chance against the powerhouse characters.

[Jasdoif]

Pardon me for sounding sardonic, but...so?

It's always a good thing to be aware of. If the PCs start dying more then the DM would like, it's nice to know what changes to look at first.

[tainsouvra]

It's always a good thing to be aware of. If the PCs start dying more then the DM would like, it's nice to know what changes to look at first.

Yeah, pretty much. It's always good to know when you're changing the balance of power.

[Shhalahr Windrider]

In other words: It's an observation, not a warning.

[Thinker]

it adds risk to the situation thus it works as a deterent. Furthermore with your logic arcane mastery would never be taken by a dispeler/counterspeller mage, yet for some reason that feat is always taken.

Guarantees are always nicer to have than maybes. If you are guaranteed to succeed without having to roll above a 10, why leave it to chance?

[Konstantin]

Hi there!
To get high DC on your spells you only need to get the right feats and PrC´s. I have a Fighter/Sorcerer/Pale Master/Spellsword/Archmage (not the version from DM guide, that one sucks). Yes, he is epic of course, but his lowest DC on spells is 26+Spell level. On Necromancy and Abjuration the DC is 32+Spell level. So there is no need to change the DC-system. Just make sure wich schools you like and take the right feats.
And he is a good fighter too.

PS: If you´re ever making an Archmage, be a Sorcerer. So, so mush better.