relative size modifier

[munin]

Here's another attempt at the list (+ = Pro, – = Con, / = Situational):

Higher SM
+ Buy ST, HP, Arm ST, Lifting ST, Striking ST at reduced cost (SM +1 or more, p. B15, 16, 40, 66, 89)
+ Immune to Constriction Attack (relative SM +1 or more, p. B43)
+ Easier to intimidate, harder to be intimidated (p. B202)
+ Easier to pin, harder to be pinned (p. B370)
+ Can squeeze torso (relative SM +1 or more, p. B371)
+ Increased reach (SM +1 or more, p. B402)
+ Easier to hit when you grapple (p. B402)
+ Can trample/overrun (relative SM +2 or more, p. B404, 432)
+ Longer poison delay (p. B438)
+ Eat less frequently (p. BIO63)
+ Larger weapons do more damage (p. DF1:27)
+ Unliving, Homogenous, and Diffuse targets add SM to resistance roll vs. Afflictions (p. P40)
+ "Realistic" larger creatures eat proportionately less amounts of food† (p. S149)
– Easier to be hit (p. B19)
– Easier to be noticed (p. B19) by Vision (p. B358) or Vibration Sense (p. B96)
– Vulnerable to Parasitic Possession (relative SM +1 or more, p. B76)
– Harder to be camouflaged (SM +1 or more, p. B183)
– More damage from extreme pressure (SM +2 or more, p. B435)
– Eat more food† (pp. BIO62-63)
– Require more space and life support (p. BIO63)
– Larger equipment costs more and weighs more (p. BIO63, p. DF1:28, p. HT10, p. P50, p. UT16)
/ Increases the size of a Jumper Tunnel (p. B64) or Permeation Tunnel (p. B75)
/ Costlier to be affected with Regular spells (SM +1 or more, p. B239)
/ More likely to block line of sight (p. B389)
/ Attack counts as Large-Area Injury* (relative SM +7 or more, p. B400)

In addition, higher SM can be justification for some traits, but you'd have to actually pay for the traits themselves:

+ "Realistic" larger creatures have higher ST (p. BIO64)
+ "Realistic" larger creatures have longer lifespans (p. S159)
+ "Realistic" larger creatures might more easily see low wavelengths (p. S162)
– "Realistic" larger creatures might have a penalty to their sense of touch (p. S162)
/ "Realistic" larger creatures have higher weight (FEATURE, p. BIO64)

Lower SM
+ Harder to be hit (p. B19)
+ Harder to be noticed (p. B19) by Vision (p. B358) or Vibration Sense (p. B96)
+ Immune to Parasitic Possession (relative SM +0 or less, p. B76)
+ Undetectable by Radar (SM -1 or less, p. B81)
+ Simpler to grapple a prone, kneeling, or sitting opponent (relative SM -2 or less, p. B370)
+ Eat less food† (pp. BIO62-63)
+ Require less space and life support (p. BIO62)
+ Smaller equipment costs less and weighs less (p. DF3:8, p. HT10, p. UT16)
+ Attacks require Vision roll to notice (OPTIONAL, relative SM -10 or less, p. P76)
+ Easier to target armor chinks (OPTIONAL, p. P76)
+ Easier to get inside armor/body (OPTIONAL, relative SM -13/19 or less, p. P76)
– Vulnerable to Constriction Attack (relative SM +0 or less, p. B43)
– Harder to intimidate, easier to be intimidated (p. B202)
– Harder to pin, easier to be pinned (p. B370)
– Shorter poison delay (p. B438)
– Eat more frequently (p. BIO63)
– Smaller armor provides less DR, smaller weapons do less damage (p. DF3:8)
– Impossible to target out-of-reach hit locations (OPTIONAL, p. P76)
– "Realistic" smaller creatures eat proportionately greater amounts of food† (p. S149)
/ Reduces the size of a Jumper Tunnel (p. B64) or Permeation Tunnel (p. B75)
/ Less likely to block line of sight (p. B389)

In addition, lower SM can be justification for some traits, but you'd have to actually pay for the traits themselves:

+ "Realistic" smaller creatures can carry heavier proportional loads (p. F51)
+ "Realistic" smaller creatures might have a bonus to their sense of touch (p. S162)
– "Realistic" smaller creatures have lower ST (p. BIO63)
– "Realistic" smaller creatures have lower IQ (p. BIO63)
– "Realistic" smaller creatures have shorter lifespans (p. S159)
/ "Realistic" smaller creatures have lower weight (FEATURE, p. BIO63)

Anything else?

* So a human punching a mouse would be inflicting Large-Area Injury (STBY, mouse). I think all that means is that you average the mouse's DR (which is likely zero anyway).
† The notes about food consumption might be confusing. Larger creatures eat more food, but the amount of food is smaller proportionate to their weight. Smaller creatures eat less food, but the amount of food is larger proportionate to their weight. However, if you follow the rules from Bio-Tech (pp. 63-64), which provides detailed numbers, you'll find that the weight of food consumed is roughly proportionate to BL at most sizes.

[Figleaf23]

Originally Posted by Harald387

I don't think I'd allow an SM -6 creature to use an SM 0 human's broadsword, no matter what ruleset I was using.

So it should have been in Basic Set.

[vicky_molokh]

Originally Posted by Figleaf23

So it should have been in Basic Set.

That and also the fact about armor having 2× weight and cost per +1 SM, not just +10% . . .

[Figleaf23]

Originally Posted by Molokh

That and also the fact about armor having 2× weight and cost per +1 SM, not just +10% . . .

So I'd better warn prospective purchasers that Basic Set is faulty. Or that DF (#?) is required for play.

[Lupo]

Originally Posted by munin

Kromm once said: "SM applies as usual when grappling; if you try to grapple a mouse, you suffer its SM on your attack roll just as you would on any attack roll, and you grapple at -9 or so."<snip> I'm not sure how to reconcile his statement with 402. I can't find him saying something different.

I guess that was just an oversight. The Basic Set should take precedence since Kromm wasn't commenting specifically on Grapple, but on SM in melee combat.

I could almost read 402 as being a bonus to hit while grappling (hitting with one hand after grabbing them with the other) instead of to grapple, except for the very last sentence of the example (which says "... to grapple ...").

No, B402 is quite clear. The bonus to hit is FOR GRAPPLING.

EDIT: I just want to say that I greatly prefer Kromm's answer to 402. It makes more sense to me. Trying to grab someone should take the same modifier as trying to touch or punch them.

If this is the case, a negative Size Modifier should *definitely* be an advantage.

Originally Posted by Figleaf23

So I'd better warn prospective purchasers that Basic Set is faulty. Or that DF (#?) is required for play.

Well, sometimes I do feel like Dungeon Fantasy is intended to be required for "actual" play.
The Basic Set sometimes is so "general" and abstract, it seems it has been intended for collectors, rather than for players.

Dungeon Fantasy not only changes some things for genre/style reasons, it also "corrects" and simplify many Basic Set rules that are too clumsy / too vague to be actually used in play.

In Dungeon Fantasy it looks like the author was actively thinking about "how will this rule be used in play?" "How will this work, in practice, for GMs?"
The Basic Set rarely gives that impression. And this is not a good thing, obviously...

[vicky_molokh]

Originally Posted by Figleaf23

So I'd better warn prospective purchasers that Basic Set is faulty. Or that DF (#?) is required for play.

The only reasonable interpretation is that the 10% is an extra for the special order (since Basic doesn't discuss SM/mass progression for armor and stuff in general, but merely has a note for Gigantism).

[trooper6]

Originally Posted by Figleaf23

So I'd better warn prospective purchasers that Basic Set is faulty. Or that DF (#?) is required for play.

No need to get snippy. Just don't use the rules in DF if you don't want to. I've run many a game without it and everything was fine. This doesn't mean that the Basic is broken or that DF is necessary.

With GURPS it has always been that the Basic rules are just that. The basics. Then, if you want, you can go pick up more specialized books and incorporate the extra rules there...or not. There are a LOT of extra rules and rules changes in Martial Arts, but that doesn't make the combat rules presented in the Basic set faulty...and it doesn't make Martial Arts required for play.

The basics give a baseline, and then indications about outliers. SM-6 and SM+6 people are not really baseline. So there are some rules about them in the Basic, and more in the DF line...which, as a Dungeon Fantasy line often deals with creatures such as Pixies and Giants...so you can go there if you are interested in some enhancements to what was presented in the Basic set.

[damon]

the trickiest thing about the relative rules, as realistic as they are.. is the addition that someone with gigantism (which could be a regular human) will have -1 to hit his normal sized opponents in melee combat. that's a pretty big penalty, and i'm not sure the bonus to grapple balances that out. Though I guess you could say that large characters *should* grapple more often as it makes sense for them as characters. (the main reason i'm thinking about this is that in our current game i'm playing a sm -1 girl, and the other character is a sm+1 beast of a knife fighter; it would probably be not kosher to introduce these rules midway through an adventure, but they do make slightly more sense)

[trooper6]

Originally Posted by damon

the trickiest thing about the relative rules, as realistic as they are.. is the addition that someone with gigantism (which could be a regular human) will have -1 to hit his normal sized opponents in melee combat. that's a pretty big penalty, and i'm not sure the bonus to grapple balances that out. Though I guess you could say that large characters *should* grapple more often as it makes sense for them as characters. (the main reason i'm thinking about this is that in our current game i'm playing a sm -1 girl, and the other character is a sm+1 beast of a knife fighter; it would probably be not kosher to introduce these rules midway through an adventure, but they do make slightly more sense)

And also remember that Martial Arts introduced Armed Grappling Rules...so your knife fighter could be making armed knife grapples...taking advantage of size. Also, the bonus to grappling for SM is RAW, so even if you don't use relative rules, the knife fighter should be getting that +1 to grappling rules.

[damon]

Originally Posted by trooper6

And also remember that Martial Arts introduced Armed Grappling Rules...so your knife fighter could be making armed knife grapples...taking advantage of size.

I see the grab and smash box, and the bit about using long weapons in close combat... is there anything else i'm missing?

Originally Posted by trooper6

Also, the bonus to grappling for SM is RAW, so even if you don't use relative rules, the knife fighter should be getting that +1 to grappling rules.

which makes the addition of relative rules pretty much just bad news for the bigger gentleman, doesn't it.