Balancing new racials

[javascripter]

So, currently I am working on a custom setting with custom races. I want to balance the races against each other and decided to have them at the OP amount of 20 RP because otherwise undead don't have much flexability. I have multiple undead races that I want to have a negative of dissolving in water, probably with some form of acid damage for contact with water? I'm not 100% sure the best way to do it, but I figured something like 10d4 acid damage for complete submersion, 8d4 for rain, 6d4 if someone hits you with a vial of water, or 2d4 if you just contact a sizeable surface of water. However, I have no idea how that would change the balance of the race.

On this (http://www.d20pfsrd.com/gamemastering/other-rules/creating-new-races) page there are recommendations for creating a new race, but no recommendations for adding new abilities.

[SkipSandwich]

I think your damage values are a little bit on the high side, I would just do 10d4 for total submersion, 5d4 for heavy rain/drenching, and 2d4 if you get splashed with a vial or flask worth.

As for how to price it, water may be a fairly common element, but it is not commonly weaponized, so this is not likely to come up often, I would say this weakness is worth just -1 RP.

In general the weaknesses seem to follow the following rule of thumb;

A minor determent under a common condition or a significant detriment under an uncommon condition is -1 RP

A significant detriment under a common condition is -2 RP

In practice, a races weaknesses will never be as significant as their strengths since players play to minimize weakness anyway, vampires don't adventure in the daytime, these undead won't become sailors.

[javascripter]

Ok, thanks. I would expect people to come up with some sort of umbrella or cloak to wear in rain anyway, so that they aren't completely wrecked by being in a jungle or something similar.

Followup question, I want this race to be able to transform into dust and move quickly, and think a modified gaseous form would work. I don't think it makes sense for resistance except for against piercing, slashing, and bludgeoning, the race is already immune to poison as an undead. I want it to be intended to be used for longer travel or escaping combat; does 1 per day (with duration as long as you want it to be) and flying speed 60 sound good for that, and what would it probably be? 2 RP? 3? How would removing the ability to fly more than 5 feet above a solid surface change it, and how would changing the action to end the effect change it?

EDIT:
Dust Form (1/day): Members of this race may turn into a dust cloud and gain a fly speed of 60, with the restriction that they can’t fly more than 10 feet above ground or water. They may fly over chasms up to 60 feet across. While in this form, they gain resistance 10 to piercing, slashing, and bludgeoning, automatically succeed on all fly checks, can fly through small holes or narrow openings, but they can only take a move action and use their action to run every turn they don’t end the effect. Ending this is a full round action that doesn’t invoke attacks of opportunity. There is no time limit on how long one may stay in the form of dust.

I feel like that is worth 2 RP? (Also taking into account that they have a base speed of 40 and are immune to exhaustion.)

[SkipSandwich]

according to the guidelines, a 1/day 3rd level spell-like ability like Gaseous Form is worth at least 3 RP, but your described ability is strictly better then Gaseous Form due to the better fly speed (60ft versus Gaseous Form's 10ft).

Overland flight is 40ft for 1/hour per level and would be 4 RP to cast as a spell-like 1/day

I'd say a single spell-like that combines the features of both for 40ft fly speed for 1 hour/level with the defenses of Gaseous Form would be worth about 5 RP per daily use.

In general spell-like abilities or other abilites that can be aproximated by spells cost (Spell level X Daily uses) in RP. Limited to 4th level spells or lower.

If it's a strictly utility effect like Detect X or Alter Self (Humanoids Only) the rule seems to be you can have it At-Will a x2 to the cost. (limited to spells of 3rd level or lower)

[javascripter]

I personally would disagree (conditionally) and say that this ability is weaker than gaseous form for the purposes of combat due to the fact that nonmagical nonbludgeoning/piercing/slashing will still damage, and that would include the water. Also, on the same turn as coming out of gaseous form you can do a swift action if you happen to have one, which you don't do with this, though that is so minor I don't think it will matter. Although I suppose it would be nice for positioning.

However, I do understand what you are saying with it being faster and it would definitely cost more than 2 RP. And it would definitely be good for escaping dangerous situations.

I do however, think I will modify it more towards what you suggested with 1 hour/level. It would be kind of ridiculous not to. I do like how overland flight gives a long distance travelling speed.

So, modified:
Dust Form (1/day): Members of this race may turn into a dust cloud and gain a fly speed of 30, with the restriction that they can’t fly more than 10 feet above ground or water. They may fly over chasms up to 30 feet across. While in this form, they gain resistance 10 to piercing, slashing, and bludgeoning, automatically succeed on all fly checks, can fly through small holes or narrow openings. While in this form the users material armor becomes worthless, and all their gear becomes a part of the dust. When travelling overland with this, one may travel at 12 miles per hour without taking any penalties. Even magic that can be cast without any components may not be cast in this form, and no attacks may be made in this form. Continually active items remain in effect. Ending or using this is a full round action that doesn’t invoke attacks of opportunity. This lasts for 1 hour/level.

Also, thank you for your help. I have no idea why most of this stuff isn't on the page for creating new races. Unless it is and I missed it. But you are very helpful.