Multiplayer Interactive-Fiction Game-Design Blog

The NPC-conversation wall

29 August 2006

by Mike Rozak

Discuss on www.mXac.net/forums

I am a mouse running betwixt the feet of elephants. Consequently, I spend inordinate amounts of time figuring out where the elephants will roam.

The elephants (major MMORPGs)

• 
  Armies - Players can hire mercenaries. Standard RTS (real-time strategy) stuff. Armies tie in well with "Castle sieges" and "Pets and henchmen".
  
• 
  Card games (???) - I'm not so sure about this one. Adding card games, chess, etc. encourages socialisation (especially while players are waiting to meet up), which improves stickiness. However, card games are a dime a dozen on the Internet.
  
• 
  Castle sieges - Half the major MMORPGs already have this. Expect more to implement it in the future.
  
• 
  Eye candy - Eye candy not only sells, but it creates a barrier to entry for the smaller companies.
  
• 
  In-game advertising - It'll happen, even in fantasy worlds.
  
• 
  More story - Mainly accomplished by more content and more instancing. "More story" is already well under way in many major MMORPGs.
  
• 
  Pets and henchmen - Just imagine incorporating elements of The Sims (offline) or any of the numerous pet-raising games. Players' pets might stay in the game even when players log off, and inevitably interact with one another... "Your pet dog attacked my virtual-child!" or "Your butler eloped with my Amazon-warrior guard!"
  
• 
  Property game - Why do MMORPGs only let players own one house? Why not dozens? Why not including a property rental/development game? Think of Sim City (or XXX Tycoon), but on a small scale; Who can build the best suburb in Gondor?
  
• 
  Racing - Car racing. Dragon racing. Ship racing. Whatever. This ties in well with "Ship battles".
  
• 
  Ship battles - Either spaceships or sailing ships. One important aspect of ship battles will be ships that are manned by several specialist players (gunner, navigator, etc.) who work together. Being able to walk around the ships is also important. Without these two elements, ships are nothing more than machine-shaped avatars.
  
• 
  Sports - Capture the flag. A game of football between the orcs and elves. Quiddich. Betting. Fixing a match. It's already starting to happen; As Raph Koster pointed out, high-level raids are very sport-like.
  
• 
  Social tools - Built in voice chat. MySpace-like functionality. Move the BBS into the game. "Dating" services designed to hook like-minded players up. Etc.
  
• 
  Trading game - The traditional "crafting" game in MMORPGs already includes some trading aspects, but I can easily imagine a different game: buying a load of dolls so they'll be at market in time for Christmas, shipping them, waiting for the shipment to arrive, hoping that the shipment arrives at all, paying for guards to protect the shipment, finding a retailer, etc.
  
• 
  User-created content - Several MMORPGs are already heading down this road.
  

• 
  Lots of player-vs.-player and player-with-player.
  
• 
  Player-vs.-computer is limited to activities that don't require NPCs to talk much. (I'll discuss this later.)
  
• 
  For the most part, existing single-player games are absorbed into a multiplayer world.
  

Since I am merely a mouse, I also need to watch out for the minor MMORPGs (budgets less than $20M). Here's what I think they'll be up to:

• 
  Alternative financial models - Smaller companies will experiment with financial models that the major MMORPGs won't touch.
  
• 
  Catch-up - Many of the minor MMORPGs have dreams of being major MMORPGs, so they'll spend a lot of time implementing major-MMORPG features, always trailing a few years behind on any given feature.
  
• 
  Exclusivity - Worlds that are by-invitation only, or which are designed so that they "scare away" standard players.
  
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  Game masters - Not just product support personnel within the game, but people with actual power to make in-game events happen.
  
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  Niche communities - These are communities that the major MMORPGs either don't want to attract, or don't bother to cater to.
  
  • 
    Adventure gamers - One or two minor MMORPGs will target adventure gamers. There aren't enough adventure-game players for major MMORPGs to bother with.
    
  • 
    Minor languages/cultures - The major MMORPGs will only ever be translated into the major (six) languages. If you want a Swedish-language MMORPG based on Swedish mythology, you'll be playing in a minor MMORPG.
    
  • 
    Roleplaying -Right now, text-MUDs are a haven for roleplayers. Over the next few years they'll migrate to roleplaying MMORPGs.
    
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  Niche settings - Cyber-punk, 16th century England, an ant's life, etc.
  
• 
  Players can change the world - Major MMORPGs won't let players change the world. Many minor MMORPGs will embrace player participation.
  
  • 
    Player government - A few minor MMORPGs will emphasise player politics, a feature that major MMORPGs are unlikely to include.
    
• 
  Scripting sub-game - Who can write an AI that kills the most orcs? The sub-game is about writing a script to control your avatar, not about controlling your avatar directly.
  

You may have noticed that I failed to include "more intelligent NPCs" in either the major or minor MMORPG list.

There are two kinds of "intelligence", neither of which will be used in MMORPGs (or so I think):

• 
  A.I. that makes the NPCs/monsters better competitors - For example, AI that enables orcs to fight strategically against players.

  This won't happen because (1) AI uses up a lot of expensive CPU on the server, and (2) those players that wanted more of a challenge would take part in PvP.

  
  
• 
  A.I. that provides NPCs with a perceivable personality, and which, by necessity, includes player-to-NPC conversations - Imagine a world where you could wander around and talk to the NPCs. A world where the NPCs weren't just vending machines, but where they had personalities, opinions, laughed, told jokes, got to know you, etc. Unlike real players, NPCs would always stay in character, and would be designed to "selflessly" entertain you, something that a real player would never do.
  

The "NPC-conversation wall" consists of the following elephant-blocking stones:

1. 
   For the most part, players aren't requesting conversational NPCs - They ask for more weapons, more monsters, better graphics, ship-to-ship combat, etc. They either don't think that conversational NPCs are possible, or don't want them (perhaps because the game-player demographic is self-selected to not care about such things).
   
2. 
   Intelligent NPCs require much more server-side CPU - A factor of 10x the server-side CPU currently devoted by MMORPGs is easy to imagine. 100x is also possible.
   
3. 
   Intelligent NPCs require enormously more server-side memory. After all, a NPC won't be realistic if it forgets that it talked to you just yesterday. Just consider of the numbers: An average MMORPG server has 3000 concurrent peak users, which implies 15,000 players, each with 4 characters each, or 60,000 characters. 60,000 characters times 1000 NPCs is 60,000,000 relationships to keep track of! Even if most relationships are only tens-of-bytes of data, many will be several kilobytes.
   
4. 
   Player density must be low - A typical MMORPG NPC can "talk to" a dozen players at once since the NPCs don't really talk; they just display private dialog boxes on each player's screen. A realistic and believable NPC wouldn't be able to do this, and would only be able to talk to one, maybe two, players at a time. This either requires a much lower player density, or many more NPCs, such as several weapons merchants in the same area.
   
5. 
   Text-to-speech - MMORPGs are transitioning from text-based NPC dialogues to recorded speech; recorded speech makes for better eye candy than text, as well as working synergistically with 3D visuals. Unfortunately, recorded speech severely constrains the ability for NPCs to carry on a dialogue because its impossible to record every single utterance that might come out of a NPC's mouth, especially when multiplied by the number of NPCs.

   The only solution to this problem is text-to-speech. Unfortunately, text-to-speech sounds lousy and will scare away most players. It sounds even more lousy when intermixed with recorded speech. Any MMORPG that already uses recorded speech (which will soon be almost all of the major MMORPGs) will find it (nearly) impossible to transition to text-to-speech.

   
   
6. 
   Typed responses or speech recognition - No matter how socially intelligent a NPC is, if a player's responses are limited to a menu of four phrases, the NPC will only have four possible responses, nullifying any advances in intelligence.

   There are two solutions: Either allow the player to type in a response and use natural-language understanding to interpret what the player said, or use speech recognition to transcribe the player's speech before passing it onto the natural-language understanding system.

   Unfortunately, current natural-language understanding requires that players forgive it's limitations; players can't just say anything they like, much as text-adventure players continually run into the "guess the verb" problem.

   Nor do players like to type (or even know how). Sadly, typing is the only option since speech recognition doesn't work well enough yet.

   
   
7. 
   Large number of NPC animations - In games such as Oblivion, where NPCs are smarter than your average MMORPG NPC, you see another problem: Characters have a limited palette of animations that they can perform, mostly involving movement and combat. This limits how much personality can be expressed by the NPCs; Theoretically, one NPC might swagger, while another might daintily sip her tea. Standard MMORPG animations don't include "tea sipping" or "swaggering", let alone "dainty tea sipping". Needless to say, NPC animations are very expensive to produce.
   
8. 
   Faces - Faces are critically important for realistic NPCs. Unfortunately, the following problems arise:
   
   • 
     MMORPG UI needs to be redesigned to that NPC faces are more than just a few pixels high. They actually need to occupy most of the screen.
     
   • 
     As soon as faces are enlarged, players will realise that the faces all look the same. To solve this, MMORPGs will need more complicated and varied facial geometry, textures, hair, jewellery, clothing, etc. This means higher development costs and more memory on graphics cards.
     
   • 
     Attempts at procedural face animation, as in Oblivion, result in characters whose facial animations are so "wrong" that the characters look mentally ill.
     
9. 
   Cut scenes - One important way to express a NPC's personality is to show how they interact with other NPCs, either through scripted actions, or in cut-scene anecdotes of their past. MMORPGs don't have any facility for low-bandwidth cheaply-produced cut-scenes.