Knockback, Weight, Armour and low ST

[Leynok]

Originally Posted by Polydamas

GURPS can't use HP as a proxy for mass because by RAW the HP of a 150 lb human, a 150 lb zombie (IT: Unliving), and a 150 lb steel ingot (IT: Homogeneous) differ by a factor of four even before you start asking yourself "are these the flimsy kind of zombies or the unstoppable kind?" or "does it have extra HP because its magic steel?"

It might not be a perfect proxy, but in realistic games HP usually scales easy enough. It also helps when you remember that "massless" HP and ST exist, and I've usually treated any "extra" HP added on as a result of magic, or extra because it's Homogeneous as massless HP that won't affect knockback. In the end, you're "knockback" score is a 0 point feature that usually hovers somewhere around HP (or well ST by RAW, but I've also used HP instead).

[Polydamas]

Originally Posted by Leynok

It might not be a perfect proxy, but in realistic games HP usually scales easy enough. It also helps when you remember that "massless" HP and ST exist, and I've usually treated any "extra" HP added on as a result of magic, or extra because it's Homogeneous as massless HP that won't affect knockback. In the end, you're "knockback" score is a 0 point feature that usually hovers somewhere around HP (or well ST by RAW, but I've also used HP instead).

GURPS can't built core rules on the assumption that a game has neither robots nor golems. That just does not fly. So the rules for knockback, collisions, etc. had to allow for normal, Unliving, and Homogeneous entities whose HP for a given mass can differ by a factor of four.

Are there any published rules which use massless HP? A game which uses them already has that extra Mass secondary statistic which I mentioned, just hidden.

Edit: They were also stuck with the decision that height and weight should be zero-point features without mechanical effects. That may have brought them more customers (and more customers means more suppliments by professional game designers), but that already makes it hard to use a 'physics model' in GURPS.

[Bruno]

Originally Posted by Nereidalbel

As previously noted, the RAW says 1 yard per point of damage rolled for ST 3 or less; 3 HP or less in your games. No such thing as negative knockback or DIV BY ZERO errors.

You know, not only have I repeatedly missed that in the basic set, I misread the quote upthread as being a quote of the OP. Which confused me, because I didn't recall the OP writing that, went back and reread the OP, and still didn't put 2 and 2 together.

Guess I got my own DIV BY ZERO REDO FROM START

[The_Ryujin]

I think a good work around would be basic lift times 0.4 instead of ST -2. If you want even more detail figure the proper ST for your weight and use it's basic lift if diffrent.

[T.K.]

Hmmm...guys...did you even read the rules for knockback on Basic p. 378?!

As RobKamm stated on the second reply to this thread the rules not only explicitly state what happens for ST 3 or less targets but ALSO spill quite clear what happens when a target has no ST score: "(...)If the target has no ST score at all (like a wall), or is not resisting, use its HP instead.(...)"

From there, you can quite easily extrapolate what happens to edge cases...

The rule is completely practical, imo

[Edges]

As a simple house rule to account for encumbrance in Knockback, you could add the encumbrance penalty to ST (or HP if you are using that instead). So, for example, someone with an 11 ST that is heavily encumbered would be treated as having a 14 ST for Knockback purposes.

'Just a thought.

[roguebfl]

ST is used for animate objects cabile f tryin to resist knock back and HP for inanimate object who mass is the Only issue.

[GodlessRose]

Originally Posted by T.K.

Hmmm...guys...did you even read the rules for knockback on Basic p. 378?!

Reading the relevant rules before commenting is a serious violation of the guidelines for this forum.

[Anthony]

The knockback rules don't have a lot of connection to reality, but it's not really possible to generate accurate knockback values if your only data points are damage and target ST/HP. On the other hand, you can generally come close enough by simply removing knockback from your games -- realistically only collisions can cause knockback, and the amount they would cause is almost totally unrelated to the damage they do and should probably be baked into the slam maneuver (a 10 HP man hitting a 10 HP man at move 10 will cause 1d damage, but after the collision both will be moving at an average of move 5, and will travel 2-3 yards before hitting the ground. A 1 hp mouse hitting a 10 hp man at move 100 will also cause 1d damage and will not cause him to move at all, except possibly as a response to pain or mess).

[dfinlay]

Originally Posted by Polydamas

GURPS can't built core rules on the assumption that a game has neither robots nor golems. That just does not fly. So the rules for knockback, collisions, etc. had to allow for normal, Unliving, and Homogeneous entities whose HP for a given mass can differ by a factor of four.

True. That said, this seems like an even larger issue for ST-based knockback. You can easily have 1 tonne robots with 2 ST (they exist in real life) or tiny pixies who magically have 20 ST. Knockback rules wind up absurd for these. When I mentioned URPS using HP as a mass analogue, I was referring largely to the collision and slam rules where they quite clearly do seem to be doing that. Hmm...

Originally Posted by T.K.

Hmmm...guys...did you even read the rules for knockback on Basic p. 378?!

As RobKamm stated on the second reply to this thread the rules not only explicitly state what happens for ST 3 or less targets but ALSO spill quite clear what happens when a target has no ST score: "(...)If the target has no ST score at all (like a wall), or is not resisting, use its HP instead.(...)"

From there, you can quite easily extrapolate what happens to edge cases...

The rule is completely practical, imo

I'm sorry. I was really tired when I posted the OP and did miss these things. As for the "if not resisting, use HP" thing, that's really weird, since HP is often higher than ST. Can I choose not to resist knockback in order to boost my knockback resistance? Additionally, the 0 ST causes a similar problem where the 1 ST, 10 HP creature resists knockback 8 times worse than if he were unable to exert force and had his ST dropped to 0.

Originally Posted by Anthony

realistically only collisions can cause knockback

Not really true. Perhaps most personal weaponry doesn't, but many attacks designed to do knockback, often with no wounding, such as shoves, pressurized water jets, etc. should definitely do knockback and at least without rewriting how those work, need to piggyback on the knockback rules. A few other attacks should as well such as, for example, a cannonball hitting your chest (with a force field letting you survive it), but I'm primarily concerned with things like Shoves.