Knockback against opponents with Flight, Clinging, Catfall
 

Hello, I'm starting a campaign shortly and one of my character's primary attacks is a massive knockback attack. Specifically, it does 2d x 10 (No Wounding, No Blunt Trauma, Double Knockback). If I did my math right, I can potentially send an elephant flying 5 yards or a standard goon around 28 yards.

I was planning to do some playtesting to get a feel for knockback and collision rules, and some interesting questions came up.

If I understand correctly, if the attack is not successfully defended, then my knockback damage applies and there is no resistance roll whatsoever (Go Flying Goon!). Opponents suffering knockback test to see if they fall down at a penalty for each yard of knockback beyond the first. If they collide with anything in the way, they will suffer collision damage.

If the knockback does not bring them into contact with any terrain, do they suffer collision damage with the ground? Any suggestions for my GM on how to calculate that if so?

What if the opponent has an advantage like Flight, Clinging, or Catfall. Can these powers be used to mitigate collision damage or reduce knockback distance? Our campaign involves enough fantasy martial arts and Powers type abilities for me to expect to encounter a situation like this.

Re: Knockback against opponents with Flight, Clinging, Catfall
 

Flight would definitely trump knockback if it could adjust the course in time.

Clinging would come into play under unusual circumstances. Catfal might well apply.

The damage comes from sudden impact, if you went the indicated distance of the Knockback, it's safe to assume you got rid of the acquired kinetic energy safely and hit the ground slowly enough.

OTOH a 5 yard 45 degree downward KB result where the ground is only 2 yards away will hurt.

Re: Knockback against opponents with Flight, Clinging, Catfall
 

I don't think this is the case. I mean, it's roughly similar to someone falling off a motorcycle, you're gonna lose a lot of skin and maybe break some bones. The only thing ablating KE is drag forces, otherwise it's just a factor of how large your initial impulse momentum was and how far you get before gravity manages to pull you into contact with the pavement.

Re: Knockback against opponents with Flight, Clinging, Catfall
 

How do you account for "adjusting the course in time?" Would they be knocked back up to their top flying speed for second and then regain control in mid air on their own turn? As I understand it the knockback distance is also the velocity in yards/sec (as its used to calculate collision damage).

This is assuming our flier is not restricted by Newtonian or winged flight or no hovering.

Would you reduce the knockback distance, by some factor? Perhaps Basic Move would act as DR against Knockback for a flying unit, since that's how much inertial control they have?

Re: Knockback against opponents with Flight, Clinging, Catfall
 

"in time" for knockback purposes is instant. You can't counter knockback any time your ground move is higher than the knockback, I don't see why air move would be any different.Basic catfall might be helpful on a collision, I never thought about it, but It certainly wouldn't reduce the amount of knockback. Clinging is problematic... it transfers the energy that should be expressed as flying off into wherever INTO your body. I'd think that would convert the knockback into some function of direct physical damage as you get "stretched"If you are knocked back the full distance, and then fall, there is no collision, if you hit anything in the span knockback moves you, you are moving at 'full amount of calculated knockback per second' and take ollision damage accordingly

Re: Knockback against opponents with Flight, Clinging, Catfall
 

If someone had flight I'd allow an aerobatics roll to halve damage, with a crit success giving no damage.

Re: Knockback against opponents with Flight, Clinging, Catfall
 

[QUOTE=nerfninja;792997]

No. They'd just kind of skid along the ground until they came to a stop. You need to am for trees and walls behind your target.


Flight wouldn't help except by making it difficult to hit the target in a way that will make it collide with anything. I would say that Clinging would double your ST for resisting knockback...but only if you happen to be standing on a clingable surface (for example, not dirt) and are actually using your clinging (which would of course halve your movement and mean that you are walking kind of funny.) As for Catfall, I think you'd need to make an acrobatics roll or something to bring it into play since you aren't actually falling.

Re: Knockback against opponents with Flight, Clinging, Catfall
 

...In the real world, when you 'just kind of skid along the ground' you're probably going to suffer a lot of superficial injuries, and potentially worse.

Re: Knockback against opponents with Flight, Clinging, Catfall
 

Halve Damage from collision or halve damage from knockback?

Re: Knockback against opponents with Flight, Clinging, Catfall
 

[QUOTE=David Johnston2;793058]Does one actually aim the direction they send someone with knockback? As I understand they simply fly directly away from you. The only way to 'aim' is to position oneself before attacking.

Assuming a 2-dimensional world, that's simple enough, but what if there is some arc to the knockback trajectory? Would they not take falling damage at least based on the max height of the arc?

The motorcycle accident analogy has me convinced. If I were GM'ing which I'm not, I think I'd apply collision damage with the ground, perhaps with some reduction (halve? or double DR?).

Re: Knockback against opponents with Flight, Clinging, Catfall
 

[edit] double post, woops [edit]

And thanks for all the great replies. This forum is a credit to the internet.

Re: Knockback against opponents with Flight, Clinging, Catfall
 

Oh I know. I've wiped out on my motorcycle at highway speed. But it was nothing like what hitting a wall would have been like, and even slight armour was enough to protect me from lasting injury.

Re: Knockback against opponents with Flight, Clinging, Catfall
 

Proper MC gear is excelent for taking the damage from something like that, but normal, non-protective clothing would have left you with lasting damage at that speed.

Re: Knockback against opponents with Flight, Clinging, Catfall
 

This is true, but if I read the OP correctly, the knockback in question is 28 yards for an average goon. That's considerably more than one move. I certainly think that if a character with flight had an action while still flying through the air, they could simply right themselves.

EDIT: And while I'm at it...

I think this would probably apply to catfall and clinging too. If you're knocked back less than your move, you have no time to act. If you're knocked back more than your move, you have an action before you hit the ground and can say something like "I'd like to make an acrobatics roll and use catfall to land softly" or "I'm looking for a tree/wall/buddy to cling to mid flight".

Re: Knockback against opponents with Flight, Clinging, Catfall
 

The goons ground Move has nothing to do with the speed he's flying through the air - that's why he takes collision damage based on 28 yards of move, not based on his ground move. He flies through the air, travelling 28 yards in a second.

There's no time for a character with a movement power to check this movement.

Re: Knockback against opponents with Flight, Clinging, Catfall
 

Derp, it's early. That makes complete sense Bruno.

So then the aforementioned powers don't effect knockback at all?

Re: Knockback against opponents with Flight, Clinging, Catfall
 

Within a second, certainly, but probably in far less than a second. Assuming that the knockback and ground are horizontal he travels 28 yards in the time it takes him to fall to the ground from standing, which is probably less than half a second. 57 miles per hour. Ouch!

Re: Knockback against opponents with Flight, Clinging, Catfall
 

Collision. Knockback is an instantaneous impulse. Collision (with ground) is you tumbling across the ground, which can be reduced by reducing your speed in mid-air via flight. I'd let any applicable talent help with the aerobatics roll, and allow the same thing even if they were headed for a tree or wall, but with some eyeballed penalties to the roll for having less time to react.

Re: Knockback against opponents with Flight, Clinging, Catfall
 

I'm confused now.
Does knockback imply that regardless of distance the victim will travel that far before their next turn (<1 sec)?

If so, then at what point should we start looking at acceleration effects(brownout, tunnel vision, blackout) or damage (accelrating at 100 g is going to have some hellacious effects, granted, you'd need supers to do that, but we can model supers)

If not, why would the victim be unable to take action when their turn comes around? If they can fly and they are in the 2nd second of a 5 second knockback induced journey why wouldn't they be able to affect their velocity?

Re: Knockback against opponents with Flight, Clinging, Catfall
 

Realistically, someone who was knocked back would continue to travel for several seconds if hit with sufficient force (the attack in question would be capable of this). GURPS does not model this.

So yes, the knockback in GURPS is how far a target flies immedately after being hit and before anything else happens. It's part of making combat simpler to resolve (which avoids your last two points).

Re: Knockback against opponents with Flight, Clinging, Catfall
 

You're referring to their sliding across the ground?

A person subject to knockback would continue to travel through the air for several seconds only if the target was launched on an upward trajectory, or if the ground sloped down. Because of the vector addition of acceleration and velocity, motion can be decomposed into orthogonals. So everything from a dropped stone to a bullet fired parallel with teh ground takes the same amount of time to hit the ground: the difference between the bullet and the stone is only how far they travel horizontally in the time it takes them to fall.

So it is with knockback. Unless you launch people upwards they take about half a second to hit the ground, regardless of how fast they are flung away.

Re: Knockback against opponents with Flight, Clinging, Catfall
 

And it should be noted that this attack is the equivalent of the amount of knockback caused by a 2d x 20 crushing attack. That should cover any damage you would realistically take as part of the sudden impulse you were experiencing.

Re: Knockback against opponents with Flight, Clinging, Catfall
 

Since we have rules for this (B468, Bailing Out of a Moving Vehicle), why not apply them to this situation? In other words: "a collision with an immovable object, at the vehicle's speed."

If it's good enough for falling off a motorcycle, it should be good enough for getting knocked off your feet by Tornado Punch.