Friday, February 4, 2011

TGTIWLTP: Normal distribution

Regarding items & Skill checks

Rather than having players continually searching for new better items like in Borderlands I’d like them to all be like the Angband ego artifacts that level up as they are used, slowly getting more magical and more powerful. The longer the avatar uses a weapon type the sharper and sturdier it becomes because the avatar looks after it. This maintenance is a part of the weapons skill.
Also the avatar becomes used to the weight and feel of the weapon and so grows sentimentally attached to it, after certain time periods they notice new places that magical gems can be placed to give the weapon special abilities, like firebrand.

Instead of every possible damage output being equally likely computers should be powerful enough to calculate a normal distribution for each weapon then randomly select one of the probabilities to calculate how much damage is done. I think this will be more interesting than the regular way.

The likelihood to hit is effected only by the skill with that weapon. The effectiveness of the attack is determined by the weapon. Attacks must penetrate the armor first. Let armor use the soak calculations. So a certain amount of the attack is soaked by the armor.
Likelihood to hit:
6σ - 2σ hurt myself
2 σ – σ not even close
σ - μ near miss (effect may trigger)
μ - σ success
σ - 2σ armor penetration
2σ - 6σ critical success + armor penetration
Standard deviations above and below these only give bonuses to learning the relevant skill. This normal distribution is based off 100% calculations. It is buffed by the skew for the relevant attack skill of the attacker. To hit is debuffed by the skill with that weapon of the defender as well as the defenders generic evasion skill. Thus entities with a really good dodge can get their attackers to hurt themselves.

Effectiveness of action:
Material quality changes the mean and stdev of the item. Speed it effected by the overall weight of all equipped equipment.

Item stats:
Material – effects quality
Weight – effects overall speed
Damage: Mean
Damage: Standard Deviation
Sentimental (increases over time, at milestones gives buffs)
Durability (decreases over time until item breaks)

1 comment:

  1. In D&D you typically roll 2 dice for an action or a damage amount. 2d6, 2d8 etc. Rolling 2 dice gives a standard deviation, albeit somewhat staggered. There was also compensation for a standard d20 roll in that a 1 was alwasy a critical miss (in which the DM invented a way that the action attempted failed catastrophically) and a natural 20 always hit, regardless of the odds.

    Std deviations are cool, and some angband variants use them a fair bit. Just be carful that if you're linking skill advancement to a random chance, that there needs to be some sort of agency too (that the player feels they have been the one that has contributed directly to their character's development)