Rethinking SM

[Anthony]

Part of the problem is that realistically what you use for SM is going to depend on the use case.

In cases where cross-sectional area is critical (perception, random saturation of an area such as an attack with bombardment) averaging (SM for length) and (SM for width) and adding 2 is mostly correct, and generally has the same effects as Tyneras' chart.

For attacks, the realistic implementation is to roll for every dimension in which you can miss -- that's usually height and width for thrusting and missile attacks, height and depth for swing attacks. This is quite inconvenient so I entirely understand why GURPS doesn't do it, but it turns out that what matters is mostly the smaller dimension -- if you're 10- to get the width right and 14- to get the height, you're 41.8% to get both, which is about 9-.