I've been working on creating a decentcraftingsystem for tabletop games for as long as I've worked on this blog, and then some. I've discussed some of the hurdles to doing so before; the things that make crafting interesting in MMOs don't apply in tabletop gaming. There are big issues with itemization scaling. And so on. A conversation with Kainenchen got me thinking about this again the other night, and today I think I had a breakthrough, though I won't know until it's all written.
Part of the itemization scaling problem is that passive benefits are very powerful. If I give weapons, armor, and shields ever-increasing bonuses to their relevant abilities, those will in turn stack with their magic items, and while it may remain playable, it will skew the balance axiom of the game in a way I feel obligated to avoid in order to call this valid design. In 4e Dark Sun, though, the designers introduced rules for weapons of substandard materials. They wanted PCs to take interest in these, while maintaining the theme that they are substandard in some way. This could be unfolded into a wider variety of "powers" associated with specific items.
Also, I recently read this excellent post, the summary of which is that Dungeoneering can reasonably be unfolded into Engineering and used as a smithing skill. The fact that dwarves get a racial +2 to this skill is just gravy for my fondness for this idea. I have currently only worked out this idea for durable goods such as weapons, armor, and shields. I have glimmers of ideas for consumable goods such as alchemy, but that needs further consideration.
Without further ado:
Assume that, at base, every item that can be crafted involves three components that vary in quality, from the very poor to the legendary. (Some components may not be physically incorporated into the final product, such as the water that quenches the heated metal. This is irrelevant to the system but useful in the fiction.) The bone of a normal animal is a very poor weapon-making material, while bronze is below average, steel is good, and adamantium is legendary. These range in value from -4 to +6 or higher.
To craft an item, the creator makes three skill checks against the item's DC; most weapons have a DC of 25, while I would expect armorsmithing to vary a bit more. Each check is modified by one of the components. Failing one of the checks by 10 or more points ruins the project. Failing the check by 5 to 9 points results in a -2 penalty, not to the next skill check but... well, I'll get to that in a second. Failing the check by 1-4 points results in a -1 penalty to that later roll. Succeeding by 5 points nets a +1 bonus, by 10 a +2 bonus, and so on.
Once you've made all three skill checks, assuming you haven't ruined the project, you will have generated a number that is anywhere from -6 to, who knows, +12 or more. This modifier is in turn applied to a d20 roll, checked against the following chart.
Above 33, even numbers result in 2/0 and odd numbers result in 3/0.
Features and Flaws
A Feature is a beneficial property in an item, expressed here as a minor, daily-use function. Features are selected by the smith's player at time of creation. A Flaw is a detrimental property in an item, expressed here as a minor, daily-use function triggered by the GM. There are typically more restrictions on when a flaw may be activated. When both features and flaws exist in an item, the smith chooses first; some features and flaws are mutually exclusive. Where applicable, a feature or flaw may be selected more than once to fill out the allotted number. It is recommended that each weapon's features be recorded on a card in the player's possession, and its flaws on a card in the GM's possession. Although these are "daily powers," their use is not tied to daily magic item uses.
A sample list of features for slashing weapons:
Keen Edge: Roll twice for damage, taking the higher of the two. Use this after hitting but before rolling damage.
Serration: When making an attack that deals ongoing damage, increase that damage by 3, or impose a -2 penalty to all saves to end that ongoing damage.
Wicked Edge: Increase the critical range of this weapon by +1 until the first time in a day that it scores a critical hit.
Weighted: When an attack using this weapon forces an opponent to move, increase the distance of that forced movement by 1.
Hooked: When an attack using this weapon misses an opponent, that opponent takes a -2 penalty to AC (save ends).
A sample list of flaws for slashing weapons:
Can't Hold an Edge for Long (mutually exclusive with Keen Edge): The player must roll twice for damage, taking the lower of the two. Use this after hitting but before rolling damage.
Soft Material: When an opponent uses an attack with the weapon keyword against the wielder and misses, the weapon is bent or notched, dealing 2 fewer points of damage until the end of the encounter.
Awkward: When an attack with this weapon misses, the target gains combat advantage against the wielder on its next attack.
Improperly Forged: One of the qualities (such as high crit or brutal) that this weapon normally possesses does not function for one attack.
Crude Grip: The weapon's wielder is denied the weapon's proficiency bonus for one attack roll.
I imagine a similar, if more extensive, list of features and flaws for other types of weapons, implements, various categories of armor, and shields. If you're running that sort of game, add in similar listings for ships, castles, or trained horses.
My thinking on materials is that there would also be pricing charts for how much one unit of various materials costs. This is one of the reasons you'd want cheap materials: with a good crafter and/or a lucky roll, you can wind up with a perfectly serviceable weapon. It also gives you a reason to seek mithril or whatever other unobtainium your heart desires.
The visible downside of this system is that you have more fiddly bits of choice and consequence going back and forth between player and GM. My hope is that this adds interest in exchange for that cost, and that it makes crafting a viable if minor part of a character's actions in game. I haven't specified time-to-create for any items, as that can vary so wildly that it needs much more thought. Nor have I created charts of materials and their modifiers to skill rolls. That's the easy part, if and only if this design holds water in itself.
Finally, there's no intrinsic reason that this idea couldn't be adapted into D&D 3.x, or into SIFRP, but the function of features and flaws might come across as incongruous in those systems.