Need help with a new spell mechanic - skill-based magic [Archive] - Wizards Community

Need help with a new spell mechanic - skill-based magic [Archive] - Wizards Community

Post/Author/DateTime Post
Valernos
05-04-05, 09:47 PM Well, I'm not sure if this is the right place to post this, but it says house rules, so I'll try it here. Please let me know if you know of a better place for me to ask this.

I've been trying to create a class (I won't post it here for now, though I will if you think it wil help) and one of the things that I'm trying to incorporate in to the class is the concept of skill-based casting. Most magic in D&D just happens. Your wizard or sorcerer chooses a spell, and barring things like arcane spell failure, the spell just happens. For the class I'm creating, I want to tie the casting to a skill check. The basic mechanic that I've worked out so far is at the end of the casting time of the spell, the caster makes a skill check with a DC equal to 10 + the level of the spell slot (not spell, to take into account the various metamagic feats.)

Now, the caster will be able to get items that grant him a bonus to his skill check, but other than that and the feats that grant a bonus to skills, I think that's about if for skill buffing.

So the basic question is do you think this mechanic works? The basic idea is that there's a reasonable chance of spell failure, but if the player puts a decent amount into buffing that skill, it should just be a small chance (though not nonexistant) for failure. I figure a feat or two should be worth the reduced risk. The basic problem I see is that if a character puts points into a class skill every level, at the high ends of play, it seems like there wouldn't be any risk for failure, especially with skill bonuses. Though on the other hand I suppose the DM could come up with situational skill penalties to balance out the problem. I've never really looked at the math behind the basic d20 mechanic though, so I don't know if this bears out in the long run.

Also, how do you think this affects the general power level of a game? I've got some bonuses in mind that offset what I perceive as a slight penalty to spell casting, and frankly, I'm willing to bet there are other aspects of the class I have in mind that are probably more important in terms of spell game balance, but I just want to make sure that this core mechanic here isn't too crazy. What do you think?
DrMorganes
05-04-05, 11:15 PM You're mucking about with a core concept of the game. This is not necessarily a bad thing, but it IS something you need to carefully consider. Viability of the idea aside, you have two basic options as I see it.

First, give this class some attractive class features to compensate for their handicap. Consider: a 1st Level wizard can cast 1 to 4 1st level spells per day, depending on race, specialization, Intelligence modifier, and application of variant rules. As you mention, these spells always go off, and saving throws may or may not apply. The mage's standby Magic Missile will ALWAYS do d4+1 damage (barring spell resistance) at 1st Level. By contrast, your skillcaster can have at most 4 ranks in any given skill at 1st level. Assuming maximum starting INT of 18, this gives +8 to your Casting Check. With a DC of 11 (10+spell slot level), you have what amounts to a 10% chance of arcane spell failure - before SR and saving throws. I'm not sure what you could come up with to balance this...

Second, implement skill-based casting across the board. This levels the field, giving all casters the same handicap and reducing the effectiveness of all cast magic by 10%. Perhaps tossing in an increased save DC would help here. This may be an appropriate variant for a low-magic campaign.

Whichever option you select, the next question then becomes, "What skill(s)?" Do you take the EverQuest route and require separate casting skills for each school of magic, or do you lump everything under Spellcraft (or some other new skill)? If the former, do you add skill points to each casting class or add some sort of compentence bonus as they level (say, 1/2 caster level to all casting rolls)?
Nor'Morgwae
05-04-05, 11:57 PM I think i understand what you are trying to do, but I don't think that this will acomplish that. All it will do is sap this class of skill points and feats. It will take an int of 18, 4 ranks in the skill and the skill focus feat to get up to the 11 for 1st level spells. From there they will simply put 1 rank in the skill every level until they hit lvl 9 then they wonly need to add anymore (their bonus will be at least +19). If this class isn't getting any bonus feats then a 1 level human has to spend all their racial bonus skills and feat jsut to be able to cast without a failure chance.

This class seems to emphasis a single 1st level build to be effective.

IF the problem you see is that magic "just happens" I don't see that to be the case. A mage's ability to cast a spell is just like a warriors ability to swing a sword. The spells he can cast are those he has the skill to cast reliably. If a wizard is in a problematic situation while ccasting (being punched or shaken) he already has to roll concentration to keep from loosing the spell. If you use this skill system expect players to ask why they can't try to cast higher level spells if they have the skill to make the DC because you seem to be equating the DC to what the game assumes to be the result of levels.

If you really want to pursue this then I suggest you look at other RPGs that have skill based casting. I think some of whitewolf's games (Mage, Werewolf, Vampire, etc) use skills for magic, but I'm not certain, I've never played any of them. Just look around your local game store, I''m sure you'll find something.
20102000
05-05-05, 06:20 AM I had a go and creating a similar class, but never got the chance to really playtest it.
You need to make the DC 10 +2x spell slot (skill levels go up twice as fast as spell levels) And i used concentration as the skill. Becasue you already have to make a roll in certain circumstances.
To balence out the more frequent casting I limited the number of spells the character can have by having a spellcraft check everytime he learns a new spell and subtracting the number of spells the character already knows.
The other method of balencing I toyed with was limiting the number of succesful spells per day per level.
The other more complicated system I considered was each spell was a skill. And you put ranks into casting that spell.
sooperspook
05-05-05, 08:06 PM I'd give the wizard a few more skill points per level. Being a sage means having to send points on knowledge skills.

I once used a similar system but split the skill use. Knowledge(arcana) to learn the spell and Spellcraft to cast it.

Added in a Backlash option ( UA has good ones for Incantations). hey , if a fighter can critically fumble his sword swing a caster can critically fumble his casting. :D

Hmmm theres an idea, use Incantions. Lowered DC of course and bring the spellpower down. This means a bit more work as you have to convert most of the PHB spells but it might work.
Loren Pechtel
05-06-05, 02:08 AM Something I have considered related to this:

You have skills in various spells. (Note: You would need a *LOT* more skill points for this. It would probably have to be independant of the current skill system). You do *NOT* have caster levels in spells, though--your caster level is a function of how much you exceed the minimum required to cast the spell by. Outright failures would only happen if you were taking a chance reaching for something a bit beyond your ability. Normally it would only affect how well the spell worked.

I had spells organized into groups where they all really were one spell just cast at various power levels. (ie, Cure Minor Wounds through True Res were all just "Healing")

Note that this was part of a system I was designing and not D&D at all.
beejazz
05-12-05, 01:33 PM I agree with sooperspook. Incantations. I wouldn't suggest lowering the DCs, but I might suggest a certain number of incantations known based on class progression, plus minor spell-like abilities in the early levels where DC20 is still hard to achieve. The class should probably look like the warlock or artificer when you're done with it.
krichaiushii
05-12-05, 09:24 PM Skill based magic might be better off as a complete revising of the current magic system, rather than just a quirk of a specific class.

Perhaps each school is its own skill (frex: Magery: Abjuration), and the skill ranks and stat bonus dictate both the save DC and how high a level of spell you can cast. Perhaps you even garner synergy bonuses with 5 or more ranks in Spellcraft and/or Knowledge (arcana).

You would need to increase the amount of skill points available to the main spellcasting classes by many; at least 4 per level - perhaps with the caveat that they must be spent on Magery skills only.

But my sample name implies arcane magic only. What to do for divine magic... and even domain spells (though the powers could remain the same).

Just a half-formed idea.

It may have merit, though.
Ranger REG
05-13-05, 02:29 AM Until Unearthed Arcana II is released:

Green Ronin's Advanced Gamemaster's Guide,
Green Ronin's Blue Rose Role-Playing Game powered by the True20 System.
IceFractal
05-16-05, 03:24 AM One problem with making magic based off a standard skill check is that it varies quite a lot. Skill checks increase basically linearly with level - Assuming you start out with 4 ranks and 16 Int, and go up to 23 ranks and 26 Int, then you've increased it by 24 points over the course of 20 levels - a bit over a point per level.

Therefore, the variance of a d20 (which is +/- 5 points on average), means that casters will be effectively 4 levels higher or lower than normal when they cast spells - and could be up to 8 levels higher/lower. That means that a 5th level Wizard will, from round to round, often only be able to cast cantrips or be able to cast 5th level spells - and could sometimes be unable to cast spells at all, or be able to cast 7th level spells.

This makes the system hard to balance, and leads to both easy victories and TPKs. To balance it, my suggestion would be to use a smaller die for the spellcasting roll, a d10 for moderate variance (+/- 2 levels on average), down to a d6 for very little variance. 3d6 seems simpler, as it keeps the average the same, but it also makes it non-linear, which adds complexity.

So, my rules for spellcasting checks would be:
Spellcasting ranks are bought like skill ranks, but they come from a different pool of points. You buy ranks in either schools or spheres (depending on class). Skill boosting factors don't apply to spellcasting rolls. A spellcasting roll is 1d8 + spellcasting ranks + ability modifier / 2.

DCs for various levels of spells are somewhat hard to set, but here's an attempt:
Spell Level: Base DC
0: 4
1st: 8
2nd: 11
3rd: 13
4th: 16
5th: 18
6th: 21
7th: 24
8th: 27
9th: 30
20102000
05-16-05, 01:08 PM The system I used was
A DC of 15 + Double spell level.
So 0(cantrip) is DC 15,1st is 17, 2nd is 19 3rd 21 etc.
For a 1st level wizard, max skill ranks is 4, and assuming a attribute of +2. That gives him +6, or a 55% chance of sucess with a first level spell.
While a 15th level Wizard would have max ranks of 18, and assuming some other pluses, would have +24. Thats enough to automaticaly suceed at up to 4th level spells, which I think is reasonable. While an 8th level spell would be DC 36, has a 45 % chance of sucess.
HiQKid
06-09-05, 10:23 AM I'm working on something similiar, but rather than just rolling for if you cast or not, you roll to see how well you cast.

Magic Skills are groups of effects and phb spells that have a similiar theme or effect (Seperated by level), and Magic Skill Points are Seperate from normal Skill Points.

Now, when you roll, assuming full ranks in a skill and an 18 in casting stat, you need a 12 or better to cast the same level as the highest level spell a caster of your phb class could cast. But, if you fail, it is not wasted, just a lesser effect. And if you roll exceptionnally well, you get a better effect.

Say, your sorcerer wants to produce a fireball. He rolls his Magic (Fire) check, and consults the skill to see what effect he had. Now, on a 12 he gets a fireball, but lower and he might only manage to produce flame, while higher might net him an empowered fireball.

If you roll high, you can take the better result than you could normally cast, or take a lower result. If you take a higher result however, there will most likely be some sort of kickback or taxing.

My system also utilizes a unique spell point and spell per day system. If your uses per day are used up, though, you can still atempt to push yourself and cast the spell. This will often be quite costly.

These are the basics, and it's still in development. Someday, I might post it up here.
steenan
06-10-05, 04:29 AM I've never playtested such a system, but if I were to implement a skill based magic in D&D, it would be something like this:

There are two "magical" skills for each spellcasting class:
-a "spell knowledge" skill
-a "spellpower" skill
For example, a wizard would have Knowledge: Arcana as "spell knowledge" and Spellcraft as "spellpower".

"spell knowledge" skill determines how many spells does a character know - I suggest skill*(skill-1)/2 points to spend, with spell cost equal to it's (level+1) squared (with total skill bonus of 7 you have 21 points, for example 3 1st level spells and 9 cantrips).

"spellpower" check minus 11 would give effective caster level (it would be rolled every time a spell is cast). It gives, on average, much more than the level of the caster (CL 7 at first level, with maxed casting stat and skill ranks), but there is a risk of failure. There should be some penalty for a failure by more than 5 - for example, casting stat damage, or HP damage, or fatigue, or more than one of those.

Let's take a first level wizard, with Int 16 and maxed ranks in Spellcraft. He has total skill bonus of 7.
He tries to cast Magic missile. If he choses to do it with CL 1 (one missile), he has 20% chance of failure, and no chance of critical failure (by 5 or more). But he also may chose to cast it with CL 5 (3 missiles) - it's much more powerfull, but he now needs a check total of 16 or more. There is 40% chance of failure now and 20% chance of critical failure (resulting in, for example, 1d6 Int damage).

There are a few ways to differentiate between caster classes with this system:
-sorcerers have to spend their skill points for two different skills, what can be hard with 2sp/lev and typically low Int, but they don't have to declare CL before rolling - they fail only when they don't get the minimum CL for a chosen spell, and the more lucky the roll, the more power the spell has.
-clerics don't learn "spells" at all - they roll their "spell knowledge" every time they want to cast, trying to improvise appropriate prayer
-wizards can learn only limited number of spells, but they are able to cast a spell from a spellbook, without learning it (it takes (spell level +1)^2 full rounds)
Aurotuli
06-10-05, 08:12 PM One method you might consider if you like the skill based magic is Elements of Magic, Revised. Its pdf file is reasonably priced and readily available at several online rpg shops.

It has a few magical skills as part of its system, and that aspect of the system can easily be applied to the other areas of magic (create, move, infuse, abjure, etc) - effectively having skill ranks replace caster level.

You can make the skills more useful - and the difficulty of casting more important - by requiring a DC check (10 + MP required to cast it) to successfully cast the spell. I'm considering using complex skill checks from UA: each element used requiring a skill check, and a final spellcraft check dealing with the general adjustment features - if any. Signature spells would only require a spellcraft check, albeit a little higher than normal due to not having to make the prior checks. This would be a good system for worlds where magic is a little wild / chaotic.

The EoMR system is not too difficult to modify if you don't like certain aspects of it, but it can be a little difficult to get used to when you first start using it. Needless to say, it is very different from the core magic system.
stone_dog
06-10-05, 11:54 PM Until Unearthed Arcana II is released:

Green Ronin's Advanced Gamemaster's Guide,
Green Ronin's Blue Rose Role-Playing Game powered by the True20 System.
There is also the Advanced Players Manual from Sword & Sorcery studios (has been working very well for me, actually) and the Black Company campaign setting, also from Green Ronin. Green Ronin love their skill based magic and you can find it in a few of their books.

As a side note, True20 is coming out setting free on non-DRM pdf next week and in print soon after.
Lord of the Ninth
07-09-05, 06:57 PM I while back another poster, whose name I sadly do not recall, made a very nice system, which I then tweaked a bit. I only have it for wizards because it seems to fit better, but here you go:

Skill Based Magic

Wizards:

Spellcraft (int)

DC=10 + (Level of Spell) + (Number of Spells Cast that Day) - (Level
of Caster)

So if you're level one and casting your first spell of the day it's easy, say a magic missile:

10 + 1(spell level) + 0 (it's the first spell of the day) - 1(caster level 1) = 10

Spell Mastery should let you treat three spells as -2 in level
(min 0).

0 level spells are treated as first level spells for first level spell
casters only. After that the principles learned in 0th level spells
should be universally known and they can be cast as a simple DC 5
check.

A failed check still counts as an attempt for determing number of
spells cast that day.

A spell caster must have an ability score equal to 10+spell level (so 19
int for a wizard casting meteor swarm), as per the normal rules.

Spell casters using magic that is beyond their ability is a fantasy staple, so I have decided to incorporate it into the system below is my mechanic for doing so. If you do not want this in your game the system does not require its use.

Casting Higher Level Spells

The DC increases by +5 if the spell is more than half your caster level (rounded up). And if the caster fails at this check he or she takes backlash
damage. So a level 1 wizard casting a Fireball as their second spell
of the day:

10(base DC) + 3(spell level) + 1(number of spells cast that day)
- 1(level of caster) + 5[higher level spell] = 18

Failure in such a case can be especially costly. Failing by less than 5 causes the spell to simply not function, however, failing by 5 or more causes Backlash. Backlash is the result of arcane energies gone awry, it deals 2d6 damage to the caster, per level of the spell they were attempting to cast (this damage is not subject to DR, SR, Energy Resistance of any sort of saving throw). Backlash can easily be fatal for a wizard of almost any level so casting a spell that is beyond oneself is normally undertaken as an act of desperation.

[edit: the poster responsible for this system is Rosisha, it's from this thread (http://boards1.wizards.com/showthread.php?t=82287) ]

Post/Author/DateTime	Post
Valernos 05-04-05, 09:47 PM	Well, I'm not sure if this is the right place to post this, but it says house rules, so I'll try it here. Please let me know if you know of a better place for me to ask this. I've been trying to create a class (I won't post it here for now, though I will if you think it wil help) and one of the things that I'm trying to incorporate in to the class is the concept of skill-based casting. Most magic in D&D just happens. Your wizard or sorcerer chooses a spell, and barring things like arcane spell failure, the spell just happens. For the class I'm creating, I want to tie the casting to a skill check. The basic mechanic that I've worked out so far is at the end of the casting time of the spell, the caster makes a skill check with a DC equal to 10 + the level of the spell slot (not spell, to take into account the various metamagic feats.) Now, the caster will be able to get items that grant him a bonus to his skill check, but other than that and the feats that grant a bonus to skills, I think that's about if for skill buffing. So the basic question is do you think this mechanic works? The basic idea is that there's a reasonable chance of spell failure, but if the player puts a decent amount into buffing that skill, it should just be a small chance (though not nonexistant) for failure. I figure a feat or two should be worth the reduced risk. The basic problem I see is that if a character puts points into a class skill every level, at the high ends of play, it seems like there wouldn't be any risk for failure, especially with skill bonuses. Though on the other hand I suppose the DM could come up with situational skill penalties to balance out the problem. I've never really looked at the math behind the basic d20 mechanic though, so I don't know if this bears out in the long run. Also, how do you think this affects the general power level of a game? I've got some bonuses in mind that offset what I perceive as a slight penalty to spell casting, and frankly, I'm willing to bet there are other aspects of the class I have in mind that are probably more important in terms of spell game balance, but I just want to make sure that this core mechanic here isn't too crazy. What do you think?
DrMorganes 05-04-05, 11:15 PM	You're mucking about with a core concept of the game. This is not necessarily a bad thing, but it IS something you need to carefully consider. Viability of the idea aside, you have two basic options as I see it. First, give this class some attractive class features to compensate for their handicap. Consider: a 1st Level wizard can cast 1 to 4 1st level spells per day, depending on race, specialization, Intelligence modifier, and application of variant rules. As you mention, these spells always go off, and saving throws may or may not apply. The mage's standby Magic Missile will ALWAYS do d4+1 damage (barring spell resistance) at 1st Level. By contrast, your skillcaster can have at most 4 ranks in any given skill at 1st level. Assuming maximum starting INT of 18, this gives +8 to your Casting Check. With a DC of 11 (10+spell slot level), you have what amounts to a 10% chance of arcane spell failure - before SR and saving throws. I'm not sure what you could come up with to balance this... Second, implement skill-based casting across the board. This levels the field, giving all casters the same handicap and reducing the effectiveness of all cast magic by 10%. Perhaps tossing in an increased save DC would help here. This may be an appropriate variant for a low-magic campaign. Whichever option you select, the next question then becomes, "What skill(s)?" Do you take the EverQuest route and require separate casting skills for each school of magic, or do you lump everything under Spellcraft (or some other new skill)? If the former, do you add skill points to each casting class or add some sort of compentence bonus as they level (say, 1/2 caster level to all casting rolls)?
Nor'Morgwae 05-04-05, 11:57 PM	I think i understand what you are trying to do, but I don't think that this will acomplish that. All it will do is sap this class of skill points and feats. It will take an int of 18, 4 ranks in the skill and the skill focus feat to get up to the 11 for 1st level spells. From there they will simply put 1 rank in the skill every level until they hit lvl 9 then they wonly need to add anymore (their bonus will be at least +19). If this class isn't getting any bonus feats then a 1 level human has to spend all their racial bonus skills and feat jsut to be able to cast without a failure chance. This class seems to emphasis a single 1st level build to be effective. IF the problem you see is that magic "just happens" I don't see that to be the case. A mage's ability to cast a spell is just like a warriors ability to swing a sword. The spells he can cast are those he has the skill to cast reliably. If a wizard is in a problematic situation while ccasting (being punched or shaken) he already has to roll concentration to keep from loosing the spell. If you use this skill system expect players to ask why they can't try to cast higher level spells if they have the skill to make the DC because you seem to be equating the DC to what the game assumes to be the result of levels. If you really want to pursue this then I suggest you look at other RPGs that have skill based casting. I think some of whitewolf's games (Mage, Werewolf, Vampire, etc) use skills for magic, but I'm not certain, I've never played any of them. Just look around your local game store, I''m sure you'll find something.
20102000 05-05-05, 06:20 AM	I had a go and creating a similar class, but never got the chance to really playtest it. You need to make the DC 10 +2x spell slot (skill levels go up twice as fast as spell levels) And i used concentration as the skill. Becasue you already have to make a roll in certain circumstances. To balence out the more frequent casting I limited the number of spells the character can have by having a spellcraft check everytime he learns a new spell and subtracting the number of spells the character already knows. The other method of balencing I toyed with was limiting the number of succesful spells per day per level. The other more complicated system I considered was each spell was a skill. And you put ranks into casting that spell.
sooperspook 05-05-05, 08:06 PM	I'd give the wizard a few more skill points per level. Being a sage means having to send points on knowledge skills. I once used a similar system but split the skill use. Knowledge(arcana) to learn the spell and Spellcraft to cast it. Added in a Backlash option ( UA has good ones for Incantations). hey , if a fighter can critically fumble his sword swing a caster can critically fumble his casting. :D Hmmm theres an idea, use Incantions. Lowered DC of course and bring the spellpower down. This means a bit more work as you have to convert most of the PHB spells but it might work.
Loren Pechtel 05-06-05, 02:08 AM	Something I have considered related to this: You have skills in various spells. (Note: You would need a LOT more skill points for this. It would probably have to be independant of the current skill system). You do NOT have caster levels in spells, though--your caster level is a function of how much you exceed the minimum required to cast the spell by. Outright failures would only happen if you were taking a chance reaching for something a bit beyond your ability. Normally it would only affect how well the spell worked. I had spells organized into groups where they all really were one spell just cast at various power levels. (ie, Cure Minor Wounds through True Res were all just "Healing") Note that this was part of a system I was designing and not D&D at all.
beejazz 05-12-05, 01:33 PM	I agree with sooperspook. Incantations. I wouldn't suggest lowering the DCs, but I might suggest a certain number of incantations known based on class progression, plus minor spell-like abilities in the early levels where DC20 is still hard to achieve. The class should probably look like the warlock or artificer when you're done with it.
krichaiushii 05-12-05, 09:24 PM	Skill based magic might be better off as a complete revising of the current magic system, rather than just a quirk of a specific class. Perhaps each school is its own skill (frex: Magery: Abjuration), and the skill ranks and stat bonus dictate both the save DC and how high a level of spell you can cast. Perhaps you even garner synergy bonuses with 5 or more ranks in Spellcraft and/or Knowledge (arcana). You would need to increase the amount of skill points available to the main spellcasting classes by many; at least 4 per level - perhaps with the caveat that they must be spent on Magery skills only. But my sample name implies arcane magic only. What to do for divine magic... and even domain spells (though the powers could remain the same). Just a half-formed idea. It may have merit, though.
Ranger REG 05-13-05, 02:29 AM	Until Unearthed Arcana II is released: Green Ronin's Advanced Gamemaster's Guide, Green Ronin's Blue Rose Role-Playing Game powered by the True20 System.
IceFractal 05-16-05, 03:24 AM	One problem with making magic based off a standard skill check is that it varies quite a lot. Skill checks increase basically linearly with level - Assuming you start out with 4 ranks and 16 Int, and go up to 23 ranks and 26 Int, then you've increased it by 24 points over the course of 20 levels - a bit over a point per level. Therefore, the variance of a d20 (which is +/- 5 points on average), means that casters will be effectively 4 levels higher or lower than normal when they cast spells - and could be up to 8 levels higher/lower. That means that a 5th level Wizard will, from round to round, often only be able to cast cantrips or be able to cast 5th level spells - and could sometimes be unable to cast spells at all, or be able to cast 7th level spells. This makes the system hard to balance, and leads to both easy victories and TPKs. To balance it, my suggestion would be to use a smaller die for the spellcasting roll, a d10 for moderate variance (+/- 2 levels on average), down to a d6 for very little variance. 3d6 seems simpler, as it keeps the average the same, but it also makes it non-linear, which adds complexity. So, my rules for spellcasting checks would be: Spellcasting ranks are bought like skill ranks, but they come from a different pool of points. You buy ranks in either schools or spheres (depending on class). Skill boosting factors don't apply to spellcasting rolls. A spellcasting roll is 1d8 + spellcasting ranks + ability modifier / 2. DCs for various levels of spells are somewhat hard to set, but here's an attempt: Spell Level: Base DC 0: 4 1st: 8 2nd: 11 3rd: 13 4th: 16 5th: 18 6th: 21 7th: 24 8th: 27 9th: 30
20102000 05-16-05, 01:08 PM	The system I used was A DC of 15 + Double spell level. So 0(cantrip) is DC 15,1st is 17, 2nd is 19 3rd 21 etc. For a 1st level wizard, max skill ranks is 4, and assuming a attribute of +2. That gives him +6, or a 55% chance of sucess with a first level spell. While a 15th level Wizard would have max ranks of 18, and assuming some other pluses, would have +24. Thats enough to automaticaly suceed at up to 4th level spells, which I think is reasonable. While an 8th level spell would be DC 36, has a 45 % chance of sucess.
HiQKid 06-09-05, 10:23 AM	I'm working on something similiar, but rather than just rolling for if you cast or not, you roll to see how well you cast. Magic Skills are groups of effects and phb spells that have a similiar theme or effect (Seperated by level), and Magic Skill Points are Seperate from normal Skill Points. Now, when you roll, assuming full ranks in a skill and an 18 in casting stat, you need a 12 or better to cast the same level as the highest level spell a caster of your phb class could cast. But, if you fail, it is not wasted, just a lesser effect. And if you roll exceptionnally well, you get a better effect. Say, your sorcerer wants to produce a fireball. He rolls his Magic (Fire) check, and consults the skill to see what effect he had. Now, on a 12 he gets a fireball, but lower and he might only manage to produce flame, while higher might net him an empowered fireball. If you roll high, you can take the better result than you could normally cast, or take a lower result. If you take a higher result however, there will most likely be some sort of kickback or taxing. My system also utilizes a unique spell point and spell per day system. If your uses per day are used up, though, you can still atempt to push yourself and cast the spell. This will often be quite costly. These are the basics, and it's still in development. Someday, I might post it up here.
steenan 06-10-05, 04:29 AM	I've never playtested such a system, but if I were to implement a skill based magic in D&D, it would be something like this: There are two "magical" skills for each spellcasting class: -a "spell knowledge" skill -a "spellpower" skill For example, a wizard would have Knowledge: Arcana as "spell knowledge" and Spellcraft as "spellpower". "spell knowledge" skill determines how many spells does a character know - I suggest skill*(skill-1)/2 points to spend, with spell cost equal to it's (level+1) squared (with total skill bonus of 7 you have 21 points, for example 3 1st level spells and 9 cantrips). "spellpower" check minus 11 would give effective caster level (it would be rolled every time a spell is cast). It gives, on average, much more than the level of the caster (CL 7 at first level, with maxed casting stat and skill ranks), but there is a risk of failure. There should be some penalty for a failure by more than 5 - for example, casting stat damage, or HP damage, or fatigue, or more than one of those. Let's take a first level wizard, with Int 16 and maxed ranks in Spellcraft. He has total skill bonus of 7. He tries to cast Magic missile. If he choses to do it with CL 1 (one missile), he has 20% chance of failure, and no chance of critical failure (by 5 or more). But he also may chose to cast it with CL 5 (3 missiles) - it's much more powerfull, but he now needs a check total of 16 or more. There is 40% chance of failure now and 20% chance of critical failure (resulting in, for example, 1d6 Int damage). There are a few ways to differentiate between caster classes with this system: -sorcerers have to spend their skill points for two different skills, what can be hard with 2sp/lev and typically low Int, but they don't have to declare CL before rolling - they fail only when they don't get the minimum CL for a chosen spell, and the more lucky the roll, the more power the spell has. -clerics don't learn "spells" at all - they roll their "spell knowledge" every time they want to cast, trying to improvise appropriate prayer -wizards can learn only limited number of spells, but they are able to cast a spell from a spellbook, without learning it (it takes (spell level +1)^2 full rounds)
Aurotuli 06-10-05, 08:12 PM	One method you might consider if you like the skill based magic is Elements of Magic, Revised. Its pdf file is reasonably priced and readily available at several online rpg shops. It has a few magical skills as part of its system, and that aspect of the system can easily be applied to the other areas of magic (create, move, infuse, abjure, etc) - effectively having skill ranks replace caster level. You can make the skills more useful - and the difficulty of casting more important - by requiring a DC check (10 + MP required to cast it) to successfully cast the spell. I'm considering using complex skill checks from UA: each element used requiring a skill check, and a final spellcraft check dealing with the general adjustment features - if any. Signature spells would only require a spellcraft check, albeit a little higher than normal due to not having to make the prior checks. This would be a good system for worlds where magic is a little wild / chaotic. The EoMR system is not too difficult to modify if you don't like certain aspects of it, but it can be a little difficult to get used to when you first start using it. Needless to say, it is very different from the core magic system.
stone_dog 06-10-05, 11:54 PM	Until Unearthed Arcana II is released: Green Ronin's Advanced Gamemaster's Guide, Green Ronin's Blue Rose Role-Playing Game powered by the True20 System. There is also the Advanced Players Manual from Sword & Sorcery studios (has been working very well for me, actually) and the Black Company campaign setting, also from Green Ronin. Green Ronin love their skill based magic and you can find it in a few of their books. As a side note, True20 is coming out setting free on non-DRM pdf next week and in print soon after.
Lord of the Ninth 07-09-05, 06:57 PM	I while back another poster, whose name I sadly do not recall, made a very nice system, which I then tweaked a bit. I only have it for wizards because it seems to fit better, but here you go: Skill Based Magic Wizards: Spellcraft (int) DC=10 + (Level of Spell) + (Number of Spells Cast that Day) - (Level of Caster) So if you're level one and casting your first spell of the day it's easy, say a magic missile: 10 + 1(spell level) + 0 (it's the first spell of the day) - 1(caster level 1) = 10 Spell Mastery should let you treat three spells as -2 in level (min 0). 0 level spells are treated as first level spells for first level spell casters only. After that the principles learned in 0th level spells should be universally known and they can be cast as a simple DC 5 check. A failed check still counts as an attempt for determing number of spells cast that day. A spell caster must have an ability score equal to 10+spell level (so 19 int for a wizard casting meteor swarm), as per the normal rules. Spell casters using magic that is beyond their ability is a fantasy staple, so I have decided to incorporate it into the system below is my mechanic for doing so. If you do not want this in your game the system does not require its use. Casting Higher Level Spells The DC increases by +5 if the spell is more than half your caster level (rounded up). And if the caster fails at this check he or she takes backlash damage. So a level 1 wizard casting a Fireball as their second spell of the day: 10(base DC) + 3(spell level) + 1(number of spells cast that day) - 1(level of caster) + 5[higher level spell] = 18 Failure in such a case can be especially costly. Failing by less than 5 causes the spell to simply not function, however, failing by 5 or more causes Backlash. Backlash is the result of arcane energies gone awry, it deals 2d6 damage to the caster, per level of the spell they were attempting to cast (this damage is not subject to DR, SR, Energy Resistance of any sort of saving throw). Backlash can easily be fatal for a wizard of almost any level so casting a spell that is beyond oneself is normally undertaken as an act of desperation. [edit: the poster responsible for this system is Rosisha, it's from this thread (http://boards1.wizards.com/showthread.php?t=82287) ]