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Made in gb
Longtime Dakkanaut






Cheltenham, UK

Obviously, not entirely unconnected to the smoke grenades question, but I'm pondering parabolic fire: that is, the ability to shoot stuff you can see by firing over stuff that's in the way. It may apply to artillery, mortars, grenade launchers or thrown explosive weapons, so has relevance to battle and skirmish gaming.

There have been a few different approaches down the years to how to manage this. Some have used the idea of "shadow zones" - areas around terrain within which someone may be protected from parabolic fire. Some have used various systems of measurement that are more or less complex to establish the actual range to the target. At a skirmish level, you have to worry about how to accommodate targets that are inside buildings or under cover. And then, of course, there's the fun of how to establish scatter.

I've been doing some work on this recently, but I'll be interested to hear what approaches others have taken. Do you allow it? Or simply pretend it can't happen? If you do allow it, do you use shadow zones and, if so, how do you define them? Or is it easier just to let anything in the open be a target?

Speaking of targets, do you require an enemy model to be a target or allow "targetless" shots that might actually hit more enemy with the blast. And, finally, is the GW scatter dice the sine qua non of determining scatter, or do you have another method?


Automatically Appended Next Post:
After a little play-testing, I realized a mistake with the above: parabolic fire is useful even when you *can* see your target, if it is in cover of some sort. Being able to launch missiles over cover, LOS-blocking or not, is pretty handy.

This helped me out a bit, because it meant I could think about parabolic fire as a form of shooting and then modify that somehow to reflect the ability to shoot at unseen targets.

Given the ranges at play on our tables, I decided that measuring range "as the crow flies" seems the simplest solution that doesn't present any obvious inconsistencies with logic. I think the N3 situation in which it was technically possible to shoot people inside buildings was silly, though. Corvus Belli fixed it, somewhat. But I'm still inclined to think that parabolic fire shouldn't be able to target a point under horizontal cover under any circumstances.

I like targetless shooting for parabolic fire, too.

I'm yet to see a better solution for scatter than the GW scatter dice. I have another approach in mind for Zero Dark, but that's one that emerges from other mechanics more naturally than a scatter dice. A scatter dice is still a simpler and very elegant solution overall.

R.

This message was edited 1 time. Last update was at 2017/05/08 12:49:04


   
Made in us
Incorporating Wet-Blending





Houston, TX

The scatter die is pretty rough and I am not a fan, even if it is simple.

I don't like "shadow zones" as they add more complexity than they seem to add. Essentially, they are another layer of LOS calculation. Instead, I would probably simplify by saying if the model is in an open area or can reasonably access one, they can try the shot, lob a grenade, or whatever. Indirect fire through a horizontal surface is also very doable- a tent or branches won't stop a mortar round and a tin roof isn't going to help much. Even tough substance will give under a barrage of explosives, so I would say it is basically the same as firing into cover of the appropriate type. Most recommendation for fortification put penetration distance from indirect fire from 1/2 to 1/3 direct fire (though larger shells tend to penetrate better, as do delayed charges), so maybe the defender gets some sort of bonus.

Also, mortars and the like routinely rely on ranging/bounding fire, so accuracy should probably improve to a degree on subsequent shots if the shooter and target stay put.

For scatter, I would say that the greater the degree of "miss", the greater the distance from target, but scatter should probably be biased away from the shooter. Really, you could probably just treat misses as ineffective fire. If you have a critical failure threshold, then you treat as friendly fire, firing accident, etc. I mean if you don't track overshot and the like with direct fire, why do it with indirect?

To randomize location, it's not too tough. Throw a d3 for distance (short/undershot, close, far/overshot) and a d3 for bias (left, center, right).

This message was edited 1 time. Last update was at 2017/05/08 19:57:54


-James
 
   
Made in gb
Longtime Dakkanaut






Cheltenham, UK

Good point that the firer as well as the target need to have the overhead freedom to admit parabolic fire. Expressions like "if the model is in an open area or can reasonably access one" illustrate part of the challenge, though. You and I know what you mean, but when you release a game into the wild, we start having to define what we mean by "open" or "reasonably". But that's just a question of semantics - fun for people like me, but not good for a discussion.

I like the point about ranging fire. Not relevant, so much, to skirmish games but very relevant to battle-level games using this sort of shooting. In Horizon Wars I avoided the issue entirely by requiring indirect (parabolic or remotely-guided) shooting to have a "spotter" element with normal LOS. But the idea of make the fire more accurate for subsequent shots wasn't something that occurred to me.

Your point about overshot is a good one, although I take a slightly different perspective, believing that you should - especially at skirmish level - track overshots with both direct and indirect fire.

Interesting solution on the question of randomized location. Not one I'd thought of before. Would you be inclined to tie this in with the skill of the shooting unit? And do you have in mind a fixed degree of failure, or think that another dice should be rolled to determine the actual tabletop distance missed? Perhaps with the right sort of stat line, you could have a fixed "miss" distance reduced by an amount equal to the firing element's shooting stat...

R.

   
Made in us
Krazed Killa Kan





SoCal

If you have a scifi game, one way I handle this is that parabolic fire is subject to countermeasures more than other systems are.

So, if you fire something with Parabolic fire, you're subject to a 20% base chance of the shot being destroyed or reduced in effectiveness. If you're using parabolic fire while in range of a point defense or countermeasures system on the table, that chance is much higher.

   
Made in gb
Longtime Dakkanaut






Cheltenham, UK

Nice! I like the idea of counter-measures against parabolic fire. Infinity has something similar in the ability of hackers to disrupt guided ammunition, which is indirect if not parabolic.

I already have the concept of point defences - sentry guns and mines - in Zero Dark, so adding a version to oppose parabolic/indirect fire is a great idea.

   
Made in us
Incorporating Wet-Blending





Houston, TX

I would tie the degree of scatter to the firer's skill as well as the accuracy of the shot. So, for example, if the firing model is unskilled, it will tend to drift more than a trained shooter. So very skilled shooters with good spotters and gear aren't going to be drifting all over the table and likely putting it pretty close on most of the time. OTOH, unskilled shooters are much more likely to have wild shots without some luck, which makes them risky if you have friendlies nearby, but still pretty good if firing into areas where there are lots of enemies.

Counter fire is a very good consideration. Even for lower tech man portable mortars, it is a concern.

This message was edited 1 time. Last update was at 2017/05/10 14:01:06


-James
 
   
Made in gb
Longtime Dakkanaut






Cheltenham, UK

I'm currently play-testing an approach in Zero Dark. I decided - and welcome your thoughts - to tie accuracy to the Acuity (roughly intelligence) of the shooter, as their Fight (usually used for shooting) combines both accuracy and volume of fire, which I didn't feel applied to parabolic shots. Because parabolic shooting is necessarily inaccurate and difficult, the test is performed at -2 (on a scale of 1-6), so characters with an Acuity of 2 or less simply aren't smart enough to work out how to make parabolic attacks (or might be temporarily "stupid" as a result of stunning or wounding).

Like Horizon Wars you roll against a target number on d12s, generating a number of hits by forming groups of dice that exceed the target number. If you get at least one "hit" result, the player then rolls two more d12s. The higher one indicates a distance, whilst the lower one indicates the clockface direction (with 6 pointing at the shooting character) - another great reason I love d12s. The final impact point is in the direction and distance indicated from the intended target point.

If the character rolls two or more "hits", then the direction/distance dice are switched (lower one is distance, higher one is direction).

If the direction/distance dice roll the same result, the hit is perfectly on target.

If the character rolls three or more hits than for each additional hit, the player rolls and extra d12 alongside the distance/direction roll and if *any* of the results match, the shot is perfectly on target.

This means: one roll to hit; one roll for scatter; and *sometimes* a third roll alongside the scatter.

I think this works. Whether I'll count straight-up misses as duds and mis-fires or auto-scatters, I'm not sure yet.

   
Made in us
Incorporating Wet-Blending





Houston, TX

Sounds like a very workable approach. The d12 does give you a nice scatter "clock".

It sounds like in your system a straight up miss is pretty bad, since you have degrees of hits (hit with lots of scatter, some scatter, and no scatter). In that case, I would probably make the straight up miss pretty harsh like a premature detonation (place blast on firer) or let the opponent place the shot within range (friendly fire). This would thematically fit the mechanics as you are basing the attempt on Acuity, so a bad roll indicates a screw up in understanding the basics or misidentifying the target. It would also discourage loading artillery on low quality shooters unless you don't really care about friendly casualties. Which makes sense, especially for close fire.

-James
 
   
Made in us
Krazed Killa Kan





SoCal

Keep in mind, you want to have parabolic fire be somewhat effective still, and not too complicated to use/resolve.

If you look at Infinity, you get a situation where everyone is on rooftops because there's no reason not to, that puts them outside the normal area of play into places where it's hard for normal troops to engage them. Parabolic fire should help deal with this since being on a rooftop should expose them to more fire from above. However, Infinity makes it very difficult to hit with it, and time consuming too.

Meanwhile, games like Warmachine are horribly bogged down with templates, scatter rolls, and more.

   
Made in gb
Longtime Dakkanaut






Cheltenham, UK

I always found indirect fire in Infinity to be ineffective for its points cost, but I was never sure if that was mathematical or just my awful dice-rolling!

So far, the solution for ZD works nicely with 2 or 3 dice rolls to resolve, although we did need to refer to my notes to remember the effects of all the dice for the first couple of uses. The only fly in that ointment, at the moment, is what to do about missed shots.

Calling them duds is simple, but feels cowardly. I might put an experimental "missed shot" resolver in the appendix...

   
Made in gb
Sword-Bearing Inquisitorial Crusader





Near London, UK

 precinctomega wrote:
This helped me out a bit, because it meant I could think about parabolic fire as a form of shooting and then modify that somehow to reflect the ability to shoot at unseen targets.
I'd say that's generally a good idea; it keeps things as simple as possible, and it is ultimately pretty accurate to real life (the laws of physics are the same for both direct and indirect fire, but you can usually ignore or simplify certain factors in the maths for direct fire).

For my IRE project, I intentionally made it so that rather than indirect fire having a set of scatter mechanics all to itself (as it was in the original Inquisitor rules), the core scatter mechanics were adapted to work for both direct and indirect fire; by making the margin of failure more significant in calculating scatter distances, a simple hit penalty means that indirect fire is harder to hit with and, on average, scatters further.

In IRE's case, that penalty is set by the gamesmaster, based on the difficulty of the attack (throwing a stun grenade around a corner might be only -20, complex trick shots could be -60 or more), so the exact implementation wouldn't work in most games, but I do feel that it is the way to go.

That said, whether you want to consider scatter on misses at all is an important question, and depends on exactly what degree of rules crunch is worth it. It's one thing for a really detailed game like Inquisitor, and perhaps meaningful in a game where the table is fairly densely packed with models (like WH40K), but when the table is only sparsely populated, it's generally just a waste of time.
Back when Infinity did have scatter on parabolic fire, I think I saw maybe one game out of ten or twenty where a missed grenade actually hit anything else (and at least once that was due to the odd quirk of the scatter mechanics, when a model with BS 14 used a light grenade launcher in their 8-16" optimum range, rolled a 16 and scattered the shot straight back at themselves).

That's not too surprising - a 4 foot square table with only a couple of dozen models on it means there's a lot more "nothing" for a scatter to hit than actual targets. With that in mind, I would actually argue that it's something I think should be excluded from skirmish games unless they're deliberately going for levels of detail bordering on anality.

DR:80S(GT)G(FAQ)M++++B++I+Pinq01/f+D++A++/sWD236R++++T(S)DM+
Project log - Leander, 54mm scale Mars pattern Warhound titan 
   
Made in gb
Longtime Dakkanaut






Cheltenham, UK

Building on from the Explosive discussion, I'm thinking that missed ordnance will be discounted for gameplay purposes, but abandoning unexploded ordnance, botching shots and accidentally blowing up civic infrastructure will carry a campaign penalty rather than an in-game penalty.

   
 
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