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SHIP BEHAVIOR: NON-COMBATANT

This type of ship follows a "prey" model. This would be merchants, scouts, and general civilians. In general they just want to get away. Taking inspiration from the Wikipedia article on Antipredator Adaption I would suggest a few techniques.

Avoiding Detection. The Imperium requires ships to broadcast transponder signals at all times. That makes it kind of hard to be completely invisible. However keeping the energy signature of the power plant to a minimum, or not using active scan, would draw less attention to a ship. It more depends on how, in the game, you do ship detection. Whatever it is, work out what actions a ship can take to subvert it, and that's the strategy.

Avoiding Attack. This involves trying to prove that you aren't worth attacking. Bascially that the effort required to subdue the ship exceedes the reward for doing so. This can go two ways.
A ship can try to convince them that the effort is too high. It may, for example, broadcast a (possibly inflated) list of its armaments in hopes that it is more than the attacker was expecting, or do a little spin about to show how maneuverable or agile the ship is, or broadcast how connected they are with the local mafia/navy/nobility  and that if they mess with them a contract will be taken out on them.
To convince an attacker the reward is too low, they my broadcast a (possibly deflated) manifest of what they are carrying. Or, if they think that they are going for a ransom, the low class status of their passengers, the negative balance of their bank account, etc.

Avoiding Capture. Several strategies here. Ships might specialize in good scanners and maneuver drives instead of armaments. These "skittish" ships would have a low threat threshold; if they detect another suspect ship moving towards them they immediately move away pre-emptively.
Merchant ships plying certain routes can "herd" into convoys. Moving collectively gives them many more guns with which to deter other single ships from attacking any one of them. These may sync up with Naval patrols to and from the jump points for additional protection. (I use this as a plot device in two of my novels!)
Alternatively, a "herd" of ships could choose to scatter when attacked, leaving the attacking ship to only choose a single, small target. Sucks to be them, but the group, in general, does better. Even better if the "lame duck" left behind is actually a disguised Navy vessel.

Avoiding Consumption. Once a ship has been immobilized, there are still tactics it can use to mitigate the damage.
If it's got rock-solid armor, or lots of interior bulkheads with all the outer surfaces comprised of fuel tanks, it can buy time while the attacker has to blast its way in. Or, it can jettison its cargo (al la Elite). If that's what the attacker was going for it now has to slow down and pick it all up rather than blow the carrier up. A variant of that is to "surrender with terms". If the pursuer promises no further violence, the ship will heave to and cooperate in the transfer of the cargo and/or passengers. They write it off as an insurance loss, and prevent further damage.
Another last resort is offering ransom. Missiles and repairs are expensive for both sides. If an attacker can demonstrate clear superiority, it is a fair resolution for the defender to offer to wire over a chunk of "protection money" in return for being unharassed. As with handing over cargo, there has to be some basis of trust. How exactly you track the repuation of people who turn against the law is going to be very specific to the game. But if there is a way they can firmly identify with a specific clan or group, and there are repercussions to breaking your word, it can work.

All together, each of the above strategies can be taken as a spectrum that a ship could run through in the course of an attack. Or, ships can be design to be particularly good one one or more of them, and favor that tactic.

Wow, great reading for me this morning!  Thanks for helping to inspire us here in AI development land.  I think it's probably worth adding a few thoughts that reading both jjaquinta and Flatfingers has inspired me:

1. jjaquinta's ideas of role-based "passive" behaviour is definately the right direction. local ships is definitely something I am working on because we want "politics" of various factions + races to play a big part in NPC's attack/defend/feel logic.

2. Flatfingers tactics vs. strategy is also right on.  I see it the same way, the tactic of a ship is based on it's type and it's "mood", as well as its opponent, and the landscape (e.g. nearby planets/asteroids, starbases, etc.).  the strategy of a faction or a group of ships is more complex and is a "guiding coordinating principle" behind an objective.  I'm doing this by giving ships a tactic, creating groups of ships that follow a commander, and giving commanders the ability to over-ride the tactics of an individual ship and set the course for that ship based on the strategy.   All this is being coded right now, as I've only just finished the "passive" behaviours, and now moving on to active behaviours.

3. RE: Coordinate systems/ NPC Movement, there are very few shortcuts I can implement right now.  it may be possible to use hash tables, and more later, but for now, I'm doing everything by the numbers.  I do have a few "3D vs 2D" shortcuts, I can't tell you about yet… but in general, the math is the math.  I have to do it this way, because our huge variety of ships, ships speeds, random objects in space, moving objects in space, etc… and my desire to make ships behave "as close to players as possible".. means I can't take shortcuts.  (at least not until we are solidified on all the ship types and objects, etc… even then, shortcut code may not be worth it, as server capacity is a non-issue).

Hope this continues to give insight, and very much appreciate the thoughts and feedback!  You guys are inspiring for sure!  (now go tell your friends you are helping design a game, and spread the word!)

Post edited 7:46 pm – April 25, 2011 by Flatfingers

Another novel, coming right up!

A. NPC Combat Tactics
  1. "Tactics" != "Strategy"

One things I enjoy discussing is the point that tactics are about the exploitation of local environmental phenomena for short-term advantage. This is very different from strategy, which is about planning for large-scale operations over a long period of time with logistics playing a signficant role. (http://flatfingers-theory.blog…..ctics.html) This distinction is worth making because it means that focusing on real tactical gameplay makes it possible to create real strategic gameplay as well, which confusing the two doesn't permit.

I'd love for NPC tactics to be generated dynamically to support the larger strategic objectives of the faction to which each NPC belongs (if any). A lone Aslan ship might behave aggressively if it's gone rogue, but it might bug out quickly if it's a recon ship for an ihatei fleet.

  2. Rich Environment

At an absolute minimum, "tactics" should mean more than just spamming the F3 key to apply a character's magic power on a cooldown timer. It should be more than "buffs/debuffs"; it should be more than cloning the tank/DPS/healer convention so that combat is really no more than an abstract game of "aggro management."

This requires space to be full of "stuff." The local environment of a tactical encounter needs to be rich enough in distinctively different phenomena to allow ships to use those phenomena for offensive or defensive benefits. (It would also give value to the various types of sensors and sensor operations described in the Traveller universe.)

I've written a lot on this subject for a certain other MMORPG (http://flatfingers-theory.blog…..nline.html), so I won't belabor the point. Just please provide things in space that we can hide in and behind, and that have various effects on sensors so as to create "terrain" that can be used offensively and defensively.

  3. Solo and Group Tactics

Another area that's regularly ignored in space MMORPGs is combat AI for individual ships versus groups of ships. Individual ships can jink and hide and ration out shots versus firing an alpha strike, but what about calling for help and attacking from two sides and (as noted in today's dev blog) luring unsuspecting players into an ambush?

Multiple allied ships should present the appearance (if not the reality) of communicating with each other to execute a tactical plan led by a command ship within the group. In gameplay design terms, players in search of a challenge should be able to find it not just in going up against an "elite" ship that's only more powerful because it's larded with more weapons, but in encountering relatively small ships in groups. Such groups should be a real threat, but that threat should come from the power of coordinated actions, not just bigger numbers.

Oh, and it would be nice if the Traveller "Fleet Tactics" skill had some value in Traveller AR for both PC and NPC fleets. Heh. :) (That brings up the question of whether players will be able to band together in large-scale fleets as in guilds/corps from other MMORPGs, as well as in ad hoc groups. Different thread, perhaps.)

  4. Difficulty Level

To the actual point of today's dev blog, how do you design a Traveller MMORPG so that players can find an acceptable level of challenge? The conventional approach is to create a magical "level" number for player characters (or ships) and NPCs, and then define equally-magical "zones" containing NPCs whose levels fall within a range band.

I hope Traveller AR's designers can be a little more innovative than that! Not merely for the sake of innovation, but to avoid straying too far from the source IP.

In Traveller, there are some locations (such as Imperial depots) where you would reasonably expect some targets to be extremely challenging. But for the most part, anyone of any strength could show up anywhere, so that pretty much eliminates the notion of static zones with defined ranges of specific-level mobs. Instead, I suspect that Traveller AR will need to dynamically generate opponents based on the calculated strength of the player ship or grouped ships and their crews.

Anyone feel like taking a swing at what such a calculation might look like?

B. NPC Non-Combat Behaviors
  1. Agendas

Non-hostile NPCs should be more than window dressing if possible. That means they need to have goals, and they need to have a distinct palette of actions they can take that give the appearance of moving them toward achieving those goals.

  2. Factions

The notion of "faction" is woefully underused in today's MMORPGs. In a Traveller MMORPG it could be used to determine an NPC's individual goals, as well as to support a large-scale storyline.

C. NPC Local Movement

To discuss this in any useful way, don't we need to know more about how player ships will move? Specifically, will movement be real-time player piloting through open space (which might be appropriate for a handheld device), or point-and-click to dynamic waypoints in space (which might make more sense for a Traveller game)?

If player movement is from waypoint to waypoint, AND if it's fast enough that in-system objects are essentially in fixed positions, that could simplify NPC ship movement considerably. I imagine something like dynamically creating and updating four waypoints in space for each large space object: one ahead and one behind the direction of rotation around the system's primary star (in the plane of the system's average ecliptic), and two waypoints (in the same plane) at 90 degrees to the two other waypoints. In other words, if you were looking down on the whole star system from above or below, and focused on one object and its associated waypoints, you'd see four of them equally spaced around the object, each about one diameter of the object away from the object: one leading, one trailing, one closest to the primary and one farthest away.

The purpose of this would be to make maneuvering calculations easier. For transit to a space object, you'd plot a path from your current waypoint to the waypoint on the side of the object where you are relative to the primary star. For flying past a space object, you would create a list of waypoint to fly to in such a way as to minimize deviation from a straight line between your current waypoint and your target waypoint. By dynamically updating the position of all four of an object's waypoints to an absolute X, Y (relative to that star system) every time the position of the object itself is updated, you minimize the math that has to be done during path calculation.

If player movement is real-time through open space, then some variant on dynamic waypoints might still be possible. Create and update waypoints around space objects, but just make them invisible so that only NPC ships use them for maneuvering.

Obviously this only seems simple to me because I have no clue how Traveller AR is actually implementing this part of the game. :)

Any other thoughts on this?

I remember hearing about this over at Rock, Paper, Shotgun in a comment thread discussing Gratuitous Space Battles: http://www.rockpapershotgun.co…..-prattles/ . I'd been a fan of Doug Lenat's work since college, but somehow despite being interested in both AI and Traveller I'd never heard this story about Eurisko.

After some research, the most helpful link found was this one, which may be the one (or a copy of the one) you're thinking of: http://aliciapatterson.org/APF…..hnson.html

It also got mentioned a while back on the CotI board here: http://www.travellerrpg.com/Co…..php?t=3128 and here: http://www.travellerrpg.com/Co…..hp?t=15850 (the latter of which has some excellent additional information as well as some good old-fashioned "I coulda beaten it!" chest-thumping  ).

Incidentally, Cycorp, the company that Lenat started in order to market Cyc, is headquartered in Austin. An interesting opportunity there…?