Sunday, 15 March 2015

Sizing Up PowerFrame

After this weekend, ten images and a final editing pass are all that stands between me and the release of the PowerFrame RPG PDF! I've just completed the images for the Size Comparison diagram, which is made up of 28 original animal images and some re-scaled images I'd created earlier.


I haven't blogged for a while, but now I'm getting close to completion I'm going to write an article each time I finish an image talking a bit about the section of the book it's for. I'm aiming to complete at least one picture every two weeks, so there should be another post up before the end of March.

Size in PowerFrame

The Size ratings go from -5 to 10. The measurements for Sizes 0 to 10 progress on the Fibonacci sequence: Size 0 is 1 to 2 metres; Size 1 is 2 to 3; Size 2 is 3 to 5; Size 3 is 5 to 8, and so on. Sizes smaller than Size 0 are half the dimensions of the next largest category.

In the very original version of PowerFrame, there was no Size attribute. Larger creatures had higher Strength and Toughness, and lower Attack Abilities and Avoid. When I added Size, it made sense to add it to Strength, Toughness, and Movement Abilities, and subtract it from Attack rolls, Avoid, Wits, and Stealth.

However, while this works fine for animals and unintelligent monsters, it created a problem with large or small creatures that use weapons.

PowerFrame uses different Abilities as the basis of Attack and Damage for different weapon types: Swords use Melee to attack and Strength for damage; axes use Strength to attack and Toughness for damage; some fine blades use Melee to attack and Avoid for damage.

So if larger creatures simply have higher Strength and Toughness, that means that the larger they are the more accurate they become with axes, in addition to having higher damage. On the flip-side, tiny creatures start inflicting massive damage with light blades because of their high Avoid. This runs counter to the intent, that increased Size should boost damage and damage resistance while penalising accuracy and evasion (and vice-versa for reduced Size).

In the end, I had to separate the Strength attribute from the Abilities it affects. After several iterations dealing with the problem in different ways, the final version works like this:
  • All characters pick Abilities within the normal -5 to +5 range (0 being average), plus Racial Modifiers. 
  • Size is always added to Abilities in the following situations:
    • Add Size to Strength when trying to perform a feat of strength against a static Resistance.
    • Add Size to Strength or Toughness when resisting a Physical Effect (such as Damage or Pushing) that is not based on an Ability (crossbows, firearms, traps).
  • Size Differential
    • Whenever two characters of different Size are fighting each other, or one is trying to hide from the other, the defending character must modify their rolls. The Modifier is equal to the acting character’s Size minus the defender’s Size.
    • The defender adds the Size Differential to their Avoid rolls.
    • The defender subtracts the Size Differential from Strength or Toughness when resisting a Physical Effect (such as Health loss or Pushing) that is based on an Ability.
    • The sneaking character adds the Size Differential to their Stealth rolls.
Although it may be a little fiddly and it's one more thing to remember, it does properly model larger things being stronger and harder to damage while at the same time being less accurate and easier to hit.

A lot of the time you're probably going to be playing Size 0 characters fighting Size 0 threats anyway, which means you won't have to worry about Size modifiers at all. If there was only one set of attack and damage stats this solution wouldn't have been necessary, but I think the variable weapon stats are more valuable in terms of flavour and mechanical interest.