A dynamic spellcasting system

[Bloodcookie]

As I slowly develop my homebrew setting, I've been thinking about how I want to present magic in the world. The following is what I've come up with; basically, I'm attempting to make magic less a matter of book-learning, and more a matter of enacting the will, as guided by mystic or divine insight.

DYNAMIC SPELLCASTING SYSTEM

Spells/day: total of all spell levels that would normally be granted under the PHB rules, each casting using up a number of levels equal to its own. Applying metamagic feats increases the number of levels used accordingly, and requires a full round.

Spells known: all spells from the appropriate class list that would be castable by a character with the given relevant ability score (int, wis, cha).

To cast: 1d20 + caster lvl + ability mod, vs. DC 10 + (spell lvl x 2) + 1/previous casting attempt (of any spell) made that day.

So, as you probably noticed, this system allows casters to attempt spells of higher levels than they could under standard rules, at the cost of possibly failing any given casting attempt. Is this balanced?

 

[AbeTheGnome]

i think you should keep the spells known list to spells within their realm. the progression is a balance factor in the rules. you can use the sorcerer's list. i just don't want to see a 1st level mage trying a wish spell til he gets it right. that said, i've been trying out a silmilar system in my game.

 

[Bloodcookie]

i think you should keep the spells known list to spells within their realm. the progression is a balance factor in the rules. you can use the sorcerer's list. i just don't want to see a 1st level mage trying a wish spell til he gets it right. that said, i've been trying out a silmilar system in my game.

Ah, when I said

Spells known: all spells from the appropriate class list that would be castable by a character with the given relevant ability score (int, wis, cha).

I meant that the character would only have access to spells that their ability score would allow them to cast (e.g., a wizard with int 16 could only attempt up to 6th level spells). Is that what you meant?

 

[AbeTheGnome]

Ah, when I said I meant that the character would only have access to spells that their ability score would allow them to cast (e.g., a wizard with int 16 could only attempt up to 6th level spells). Is that what you meant?

no. what i mean is that with a high ability score and a racial INT bonus, a 1st level mage could attempt 9th level spells. there's nothing to hold him back, because he basically "knows" every spell on the sorcerer/wizard list (if i understand your proposal correctly). while it's unlikely that he'll be able to "channel" these spells correctly, he can keep trying til he gets it right. odds are, if he attempts a Wish spell 20 times, he's going to tun up a natural 20 once.

 

[Bloodcookie]

You're right, I'd failed to consider the fact that a natural 20 is an automatic success (in my head, I was thinking "even with a 19 int, a 1st level caster would need to roll a 23 for a 9th level spell, so no need to worry about them even trying!" Heh.)

I suppose I could stipulate that the nat-20 rule doesn't apply to the casting system, but I'm not sure that's the best option, either. Back to the drawing board!

 

[Asmor]

You might take a look at Elements of Magic. It seems to be right up your alley. Point-based casting and roll-your-own spells.

 

[erf_beto]

In your houserule, a 1st level wizard with Int18 can cast 2 (1+1bonus) or 11(1+1*1+1*2+1*3+1*4) levels worth of spells?

If you don't want casters to Meteor Swarm at first level, maybe you could put a cap on maximum spell level allowed to know, like the PHB wiz progression (so fireball can only be cast at 5th level...), or by Int modifier (the above wizard could cast spells up to 4th spell level, gaining access to 5th at 9th level, like PHB wiz), depending on your game. Also, increase casting time in one full round for each spell level you couldnt normally cast - a 1st level wizard could cast only 1st level spells in core PHB, but with these rules he could try Dimension Door (4th) spending an extra 3 rounds and succeding in the caster level check you proposed.

 

[Ltheb Silverfrond]

You're right, I'd failed to consider the fact that a natural 20 is an automatic success (in my head, I was thinking "even with a 19 int, a 1st level caster would need to roll a 23 for a 9th level spell, so no need to worry about them even trying!" Heh.)

I suppose I could stipulate that the nat-20 rule doesn't apply to the casting system, but I'm not sure that's the best option, either. Back to the drawing board!

The Natural 20 rule only applies to attack rolls and Saving throws. Nothing Else. Not even checks to beat spell resistance.
A good think it doesn't too, because a mage could just roll spellcraft to "unmake the universe" and wait for a 20... (silly example)
Basically as long as you say "Make a check using 1d20+X+Y against DC Z" you are safe.
I like the system btw. Could work for simulating all manor of magic systems, where arbitrary limits just don't seem appropriate.

I think the DCs to check against are a bit low innitially. A level 1 mage with 18 int has a +5, meaning on a 19 or 20, he or she could use a 7th level spell! (and a mage of a race with an intelligence bonus, at level 3, on a 20, with his or her +8, can cast a 9th level spell!)

Now, of course, if you limit the spellcaster to spells known or spells scribed in spellbook, this isn't a problem.