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Tuesday, April 8, 2014

GURPS House Rules: Size Modifier, Part 1

I've broken down the price of the different components of a positive Size Modifier.

A positive size modifier acts as a large negative disadvantage. I've priced out its different components to see what it would cost if you priced those traits out individually. Thanks to Bruno on the forums for breaking down exactly what SM is.

Here's what I get for SM+1 or Gigantism for a normal human:

[Varies] Buy ST, Arm ST, Lifting ST, Striking ST at reduced cost
[5] +1 Move
[2] Immune to Constriction Attack (Relative SM +1 or more)
[1] Easier to intimidate, harder to be intimidated (Relative SM +1 or more)
[1] Easier to pin, harder to be pinned (Relative SM +1)
[1] Can squeeze torso (Relative SM +1)
[1] Increased reach (Only for unarmed attacks)
[1] Easier to hit when you grapple (Relative SM +1 or more)
[1] Can trample/overrun (Relative SM +2 or more)
[1] Longer poison delay


[-5] Easier to be hit
[-1] Easier to be noticed by Vision
[-1] Harder to be camouflaged
[-5] Eat more food overall
[-1] Require more space and life support
[-20] Larger equipment costs more and weighs more
[-1] Harder to fit under low hanging ceilings and doorways without crouching or crawling, or through narrower cracks/holes (or even doors) without an Escape roll.

That works out to a total of -20 points before applying the discount for high ST, which, realistically for a human-sized creature, will give back around four points or so. My preference is to abandon the rule that gives larger creatures a discount on ST. I don't see what purpose it could serve other than to mask the fact that high levels of ST are overpriced. I'll address that in another post. I also strongly dislike that as a method of balancing size modifiers because not all large creature have a high ST or HP. You can have ghostly creatures that are very large but have no mass at all, similarly with large nanoswarms, balloon-like creatures, jellyfish, and weird aliens and supers. If their 0-point size modifier is supposed to be balanced by cheaper ST, then creatures who aren't buying ST are getting a bum deal. Even with SM+1 creatures, the ST 10 giant is suffering much more from his size than the ST 20 giant. I don't like how the value of the trait varies like that based on which other traits you've purchased.

In Conclusion

I would turn Gigantism or SM+1 into a [-20] disadvantage, and remove any reduced cost for a high ST.


  1. Where is the -20 for more costly/heavier equipment from? And the "eat more food overall" (which implies Doesn't Eat should cost more for SM+1 or bigger folks)?

    Just curious.

    1. I made it up, like most of those prices, based on how much of an inconvenience it is. It's not worth much at all in some games. It doesn't matter all that much to a hunter-gatherer that his clothes weigh double. But it's nearly crippling for someone in a fantasy game who wants to wear armor for it to cost and weigh double. I would adjust that price for different games, but I'd err on the side of the fantasy game if I was coming up with a universal price, since fantasy games are the most popular.

      Maybe needing to eat twice as much is the first level of Increased Consumption and should give back ten points? That seems a bit much to me. I don't think Doesn't Eat should cost more for larger characters. I would charge the same price for these traits for everyone. So if a fairy needed to eat twice as much as a human, I'd give them the same amount of points I'd give a giant for that same disadvantage. And I'd charge the giant the same amount as the fairy to never need to eat.

    2. That's why I am curious. I am not really sure that "everything costs double and weighs double" is really a -20 point disad. It's clearly a disadvantage, but -20 is a lot - Berserk (6) is -20, for example. I wonder if there isn't something that model inconvenience costs a little better, canonically. Somehow I can't see it coming to -20, though. Personally if I was just eyeballing it I'd go -10, because I find the double weight isn't as bad as it seems and only applies if people insist on bigger weapons and heavy armor. That's not universally the case, even in armor-heavy games like fantasy games. And it parallels Increased Consumption.

      Increased Consumption - if SM+1 really means you need to eat double, then yes, it's -10 points. That's the cost. If you have Doesn't Eat or Drink, then you can't also have I.C. and you'd need to pay extra to remove it (easy enough - SM is a meta-trait if I ever saw one.) -5 is too little for double food requirements if a SM 0 person gets -10 for that.

      You also forgot the "Giant Weapons" perk - a SM+1 person can use SM+0 or SM+1 weapons normally, so they need to pay for that privilege if it's not long inherent in their 0-point SM package.

    3. I'm thinking of it as two different -10 disads. I agree that it's not as limiting as Berserk (6), but that one seems underpriced to me. I don't think it's worth that many points in every game, but for the kind of low-tech game where your big guy wants to wear armor, I do think it's that much of an inconvenience. Twenty points worth of disad is just about enough to cover the cost of being able to carry the extra weight and pay the extra expense. I might be overdoing it, though. I'll try this out in my next fantasy game and see if anyone takes it at -20. They never do at 0.

      I don't really like the Giant Weapons perk for this. I would rather have what weapons you can use be a function of ST here. If we start doing hand shape, that's going to lead to all sorts of weirdness with supers and aliens. I'll think about how I could factor that in here. That will be interesting to look at when I do the negative size modifiers.