skill specificity; in which I come full circle

So how general should a character’s skills be? This is a battle I have fought on ever side of but I think I’m getting close to an answer I like.

Traveller (Tabletop Game) - TV Tropes

At first (say 1978, playing Traveller) I would have said “very specific” because that felt realistic to me. I suspect I felt something else I didn’t have words for yet as well, but I would. But skills were so specific in Traveller that there wasn’t even a general rule for determining success — pretty much every skill had its own paragraph describing how to use it. That’s mighty specific!

As I matured, or at least grew older, and started to think about game design I started to appreciate the verisimilitude of generalization — or at least categorization. How much difference was there really between a submachine gun and an automatic rifle? Did they really need different skill? Even if they were different, don’t you think you could pick up the skill pretty fast if you already knew something similar? So at this point I was digging the Traveller Mercenary (Book 4) abstraction (available only for military careers though, so in a sense this is just a bucket of skills with a new name) of “combat rifleman”.

As time and experience moved forward I came to really like generalization. In degrees. Eventually I’d be very happy with “Violence” as a skill that subsumed all of that combat shit. Sure, there are different skills involved in real life usage of fists, a knife, a rocket launcher, but verisimilitude was no longer my goal, at least not through strict simulation. I felt (and still feel, for these games) that if you the player want your character to be great at rocket launchers and shitty at barfights, then don’t get into barfights. Or don’t use Violence when you’re in one. Or use a rocket launcher. That is, you can fabricate this background detail of specificity yourself. The machine doesn’t need to know it in order to crank out resolution effects.

I still like this though it’s no longer an axiom of taste but rather just another kind of game I like to play. I’m long past claiming only one game or one kind of game will satisfy me. There are too many cool things out there to sit in a corner with that one you liked when you were 12 and deny all others.

So recently we’ve been playing some classic Traveller. Here’s my character:

Brad (Mickey “The Wrench” Doberman)

Mickey is distinctly below average in all respects, but remains the hero of his own story.

UPP: 465766

Cutlass-1 Brawling-1 Mechanical-2 Ship’s Boat-2 Vacc-1

TAS Membership, Pinnace to call my own (The Stephen Foster)


That’s not a lot of skills. You’d think it would benefit from a ton of generalization. But you have to look at all features of the character, especially skills, in ways other than just how they mechanically operate in play. They are also defining characteristics — they don’t just tell you how the character will engage mechanically but also who they are.

See, Mickey sucks. He’s below average in every stat but intelligence, where he’s perfectly average. He’s not gifted by birth at anything — he’s weak, he’s slow, he’s got a nasty cough that won’t go away, he dropped out of high school, and his parents were nobodies. But on the other hand, that’s a lot of information! How come he’s so weak and sickly? Maybe the fact that he’s a Belter has something to do with that. Maybe it’s the cigars he loves. How come he dropped out of school when he had the brains to pursue it at least a little further? What kind of nobodies were his parents? Why?

Mmm, derived detail. That’s my thing. I love random values and then trying to make sense of them. Lots of people prefer to throw up their hands and say “that’s ridiculous”, “that’s impossible”, “that’s unbelievable” but I always prefer to look at stats and say “I wonder so hard how that could be that I am now making up a plausible reason”. Weird stats are stories.

Since I started by talking about skills, look at Mickey and think about that.

But let’s look at something simpler. I recently rolled a character up with a random generator and got a character with Rifle-2, SMG-2, and … Hovercraft-2.

Look at that hovercraft.

Now here’s a skill problem I have confronted many times and usually my perspective is poisoned by a need for verisimilitude rather than a consideration of what else it delivers to the game. So anyway here it is. If you can drive a hovercraft, what else can you drive? What can’t you drive?

This is the essence in finding a category or generalization: looking at “hovercraft” and deciding what acceptable siblings it might have.

And then we have to wonder, if you don’t have Hovercraft as a skill, what would happen if you tried to drive one? Could you do it badly (a kind of gradated skill, like throwing a ball, where anyone can give it a shot and get some kind of result) or can you not even try (a qualified skill, like driving or surgery, where there’s a minimum knowledge you need to even figure out where to start)?

But that’s not what’s interesting about Hovercraft as a skill. It used to be but it matters less to me than the power of it: who is this person who only knows about hovercraft? Where do you come from where this is something you know to the exclusion of all other vehicles? Who is this Hovercraft Person?

And then in play, when I play Hovercraft Hero, look what happens. Whatever we are doing in the story, if I want to exercise my agency I need to make it about either gunfire or hovercrafts. Everything that happens in game, I am steering towards gunfire or hovercraft. Or both.

These two things are what makes a game go: who am I and what will I do? Specificity makes these a puzzle with some powerful clues. I am Hovercraft Hero. I am going to fucking hovercraft this problem.

elephants and rooms

Okay it’s time to talk about D&D.

Yesterday I wrote about what I want. In that essay I took a stab at a few mechanizable points by identifying who or what is best positioned in a (fairly trad) game to provide the sauce. The purpose of this, obviously perhaps, is to both start thinking about mechanism (here are starting points) and start thinking about alternatives (here are things we could subvert). I use this method a lot, where I identify norms in order to find things to question and subvert. I am certain that it’s pretty annoying in a lot of circumstances but I find it fruitful for myself.

So in terms of market share, if you round off at, say, three significant figures, there’s really only one role-playing game. D&D. Its dominance in the market is so thorough that it needs to be examined. However, most attempts to understand this take the obvious approach of wondering why this is the case. I think this has yielded little actionable result and is also pretty old hat — you’ve seen it before. You might have done it before.

So instead of wondering why D&D is so huge, let’s ignore that. It’s not actually interesting any more (partially because it’s old ground but partially because it’s not something you can reproduce even if you figure it out). Instead let’s look at the fact of it. D&D is huge. That’s just true. So given that fact, what opportunities does it present? What is true about it that you can subvert to make your own work at least distinctive, given that you can’t reliably produce a genuine competitor without becoming equally dull (a thesis I’ll explore another time but let’s just pretend you agree with that)? You can’t compete, so what else can you be?

The obvious thing to subvert, the thing you can change that D&D can’t, a simple axis of rotation that D&D is fixed on, is the genre. The Euro-fantasy melting pot that has become self-defining. Wizards and dragons, good and evil, fabricating motivation that is best solved by beating things dead and taking their possessions. Yes I know you can do different things with the game (of course you can — the act of play is so very close to the act of game design hinging mostly on what you choose to write down after a session) but there are selling points to the game that are fixed by the text and those are magic, moral disambiguation, and combat scenes. Those are knobs you can twirl that D&D can’t. Again, you can in your D&D game; please don’t come at me with “D&D can do everything” — that’s really just an assertion of your own free will and that’s a different discussion (hint: I largely disagree that we have any).

Knobs so far:

  • magical setting
  • moral disambiguation
  • elaborate combat mechanism
  • adventure as armed robbery

The social design of D&D is also very rigid: it cannot easily deviate from a strict ref/player boundary where the ref holds many secrets (sometimes even keeping the rules secret which is super weird the more you think about it). The “players” (that is, not the ref) are largely homogenous socially though the usual leader/support/asleep sub-categories inevitably arise. But the ref is saddled with the job of establishing the atmosphere, establishing (somehow; this is never clear but it’s usually just based on hope and not mechanism) character motivations, and preparing all of the supporting material to allow play. Maps, stat blocks, and so on. This is of course marketing genius since the ref’s job is so onerous that you can sell them support tools like adventure books. Lots and lots of them!

You can subvert these too. So far then:

  • magical setting
  • moral disambiguation
  • elaborate combat mechanism
  • adventure as armed robbery
  • ref/player role distinction
  • 1:many ref:player ratio
  • motivation in ref’s creative space
  • mood in ref’s creative space
  • play material (maps &c.) in ref’s creative space

Lots of great games subvert many or even all of these. That last in particular tends to generate a lot of pats on the back when it’s upended well because it’s really a frustrating thing to get stuck with: collaborative world building is one way to do it. Creating the map as part of the main phase of play is another. This knob is particularly fun to fiddle with. If D&D is missing a major gimmick that could vastly improve it, I think this is it.

Mechanically D&D has some basics that often go unquestioned. “Stats” that define innate ability. Some mechanism of defining trained ability (D&D is weirdly incoherent here having and connecting “skills” and “levels”). A measure of how dead you’re not (so death is on the table as a failure result: we can tinker with that too). Some moderately rich simulation tools to resolve combat (how fast you are, how hard you are to hit, how easy it is for you to hit others, a list of super powers). It also insists on a fairly finely granular simulation of money (counting actual coins) and it treats equipment as part of the way you improve your character (especially their ability to murder efficiently). An awful lot of games adopt these unquestioningly and I think they merit much more serious attention. Plenty of games do without or radically change some or all to great effect.

And of course we have the progression system which is maybe the most often unexamined component when people start to design new games. The idea of progression is very infrequently examined and toyed with. Progression is a very weird one for me because it very unsatisfying: when you peek through the curtain you notice that the environment is constantly scaling with your progression meaning the numbers all get higher but little fundamentally changes. The only disparity that stays constant is that your character constantly becomes more powerful with respect to commoners. I find that disparity as a goal somewhere between weird and deeply disturbing. That is, the biggest reward to levelling up is becoming even more powerful than the vast majority of the people in the world.

So let’s summarize again. Now we have:

  • magical setting
  • moral disambiguation
  • elaborate combat mechanism
  • adventure as armed robbery
  • ref/player role distinction
  • 1:many ref:player ratio
  • motivation in ref’s creative space
  • mood in ref’s creative space
  • play material (maps &c.) in ref’s creative space
  • separation of innate and trained capability
  • hit points
  • combat simulation tools (armor, speed, &c.)
  • lists of super powers
  • lists of equipment
  • shopping as a scene
  • literal money simulation system (you count your money and buy things with it)
  • equipment as progression
  • power progression
  • antagonists keep pace with power progression
  • common folk do not keep pace with power progression

These are all ways you can deviate (sometimes dramatically) from D&D. There are many more, but I’ve tried to find categories where I can rather than deep dive on details (I also think that encourages people to think that they have turned a knob from 4 to 11 by renaming “hit points” — we need categories to understand the possible scope of change). I will emphasize again that I think you should because competing meaningfully with D&D is a bullshit goal. I don’t think you can achieve it by aiming at it. The next big thing, if there ever is one, will be a big thing because of two things: a boatload of accidents no one controls and a significant deviation from the status quo. Focus on the thing you control. You might even accidentally create some art along the way.

what do i want?

So I was trying today to distill what I want from a role-playing game in the hopes that by digging down to really basic principles I could get a better understanding for what the rules need to do to suit my needs. This is a little thought-on-the-fly and a little planned, so bear with me as I both derive and discover this.


One of the things I most want to experience while playing (and deliver if I’m running a game) is awe. I want there to be something that makes you gasp even if it’s just in your head. Now this seems to be something that is in principle in the hands of the ref or the setting material. Let’s note that:

  • delivered by the ref
  • delivered by the setting material

But what is it that delivers awe? My gut instinct is that it has to do with outrageous magnitude. The impossibly huge inspires awe. Niven’s Ringworld inspires awe, for example. In this novel Niven posits a place where at the orbital radius of a world like earth is not a planet but rather a ring surrounds the sun at that distance. It contains millions of worlds of space. It’s terrifyingly huge and the size of it is apparent from inside it, where the world forms an arch over your head. Even Iain Banks’ comparatively small orbitals, space stations that contain only a few planets worth of surface area, are big enough to make you draw a breath. Things that are too big to contain in your head give you inexpensive awe.

Age gives you awe. Things that are immensely old, like the sleeping hegemonic swarm in Vernor Vinge’s A Fire Upon The Deep or even Pham Nuwen himself in Vinge’s A Deepness In The Sky (and fractionally in ‘Deep too) inspire awe. The fact that Pham is a “normal” human who has spent a lot of time at relativistic speeds means he’s physically not all that old but he’s seen tens or even hundreds of thousands of years pass on the worlds he’s visited.

I have in my notes that improbability gives you awe but now I don’t think that’s right. Or maybe it’s another layer deeper — the really huge is partially awe-creating because it’s improbable. Same with the really old. It doesn’t have to actually be improbable, it just have to seem like it. So since I can’t think of any independent examples of this let’s throw it away. Maybe you have some insight.

Power also gives you awe but power is a tricky one, especially in games. First it’s kind of cheap and leads to escalating power struggles that swiftly become ridiculous. I used to use this a lot but it’s a dangerous game. D&D nicely codifies it with levels, handing out the toys in a regulated manner and escalating the opposition in order to create awe. But your power is mostly what’s awesome since everything else is scaling to your needs — it’s weirdly awesome to you the player, though for your character it might be commonplace. I guess my real issue with power as an awe-source is the way the whole story has to cope with it by trivializing things that are too far below the power scale — which frequently leaves things behind that I don’t want to lose. What I mean is, if you’re a 20th level wizard fighting giant astral demon fetuses (a real monster in D&D 3e, the last revision I really played out) then the every day conflicts of city life become eroded in importance. Zero level barkeeps pretty much to whatever you tell them to do. Power as a knob to turn is transformative: it changes the whole game. It’s useful for awe but it’s a spice you want to be very careful with. It changes the whole dish.


I want things to be difficult in my game. One of the songs that used to really inspire me to craft situations in games when I was a kid was Yes’ song South Side of the Sky from Fragile. Look at these lyrics:

Move forward was my friend's only cry
In deeper to somewhere we could lie
And rest for the the day with cold in the way
Were we ever colder on that day
A million miles away
It seemed from all eternity

Winter winds, desperately moving forwards hoping for safety, enduring the impossible. This is something that games generally do really badly. I would love to find a game that made you feel this kind of desperation without simply ticking off hit points. I want a narrative solution that I feel in my guts. This is a bit of a grail for me; I don’t have a solution. I think I caught a piece of it with the RESCUE method in The King Machine just because it makes the scenario happen where people need to be saved, and makes it immediate and risky. I think that’s a space I want to explore more. I think RESCUE is a flash of genius even if I say so myself and I regret removing it from the current Diaspora work.

It’s funny that this one has been so boiled away in gaming, abstracting it to, say, how many hit points you have left. Or whether you make a saving throw. It’s essential if not the whole point of most fiction. It’s usually replaced with endless fights. That doesn’t interest me as a solution though I get why it is: it’s an easy replacement. But it’s far too specific for my taste. Almost nothing in real life is a fist fight. And only slightly more is even credibly analogous to one. A fight is a very small and unusual case of the superset of hardship.

Hardship has to be delivered by the ref and by the mechanism I think.

  • delivered by the ref
  • delivered by mechanism


We need a purpose. As the actor famously demands, “What’s my motivation?!” As a player I am not content to be handed missions; this is too mechanical now and I always imagine a giant yellow exclamation point over and NPC’s head. It can be a mission, but not in a sprawling sandbox game. A game that’s about missions, that uses the mission as an episodic structure to tell tales, well I am onboard for that. That’s Hollowpoint. And it’s an elegant but somewhat specific solution.

But where else can purpose come from? The mechanism can supply it as we’ve seen. The ref can supply it via NPCs. But real motivation, real purpose, is not actually in the ref’s hands. It’s in the players’ because they need to buy in. I think the first time I realized this was when I first read a copy of Burning Wheel. In this game character creation demands that each character have a few BELIEFS — statements about the things that will motivate the character to act (and mechanically will pay the player for doing so). If you have a belief like “Arthur is the true and righteous king of the land” then you are motivated to act on anything that threatens that. It sells itself.

The problem with doing it from any other angle is that the player needs to buy in, and that’s why it generally only works when it’s the core premise (you are secret agents on a mission and here’s your mission) or when everyone’s happy with a more contrived quest-giving landscape of NPCs. It’s got to come from the player, supported by mechanism (a way to declare your motivations) and an observant ref (pressing the buttons the player laid out clearly on the character sheet).

  • delivered by the player
  • supported by the mechanism
  • supported by the ref


This is something I only recently realized how badly I want in a game. I want to feel for everyone. I want to care what happens in the world around me and not just to my character or my compatriots. Again, swinging back to The King Machine, this is why the SPILLOVER risk is important: it pushes the ref to threaten the well-being of innocents when player characters act, and therefore make a conscious decision about how much they care. It creates an active, mechanical opportunity to find compassion in play.

I think compassion is really important because it can be absent in games without anyone deliberately removing it. Back to our poor barkeep being pushed around by the 20th level wizard, we generally don’t care that she has a family to feed. These things are either beneath us or so far outside the scope of our motivations that we don’t address them since we have bigger fish (giant demon babies) to fry. But I want to care when I play. I want all of the people to have a potential story — not necessarily to tell it, but to be impacted in a way I am forced to feel.

I think compassion is very much a shared burden. The ref has to deliver it. The mechanism should support it in same way, giving it focus, making it an issue. And the players have to buy in — they have to care what happens to the barkeep.

  • delivered by the ref
  • supported by mechanism
  • supported by the player

testing the new editor

Caption test. I am captioning now.

Hmm, well here we go. I only ever type and then add an image, so let’s see if that does what I want.

Hmm. Seems okay. More steps to do what I want and more noise in front of me as I type, but okay.

It does ignore my style’s captioning option so that sucks.

As usual, an upgrade that seems to be aimed at fulfilling the need to apparently improve by changing things and adding options that are not especially valuable, while removing functionality in the original. Unimpressive, WordPress. But that’s the software development pattern: appear to be improving. Change as often as possible in order to sell assistance.


This is a bit of a deviation because it’s not about tabletop games, but rather about video games. Specifically big multiplayer “role-playing” games and a specific element of them: the guild. And honestly there’s a little political science in here because I think some people misunderstand the politics in them because they are not remotely like real world politics at their core. The drama is of course the same.

izh_classicWe want to look at power and at legitimacy. Legitimacy is the part that works similarly to the real world (in that there are no game mechanics to create legitimacy) except that it is so easy and so cheap to change your guild, that abandoning a failed leadership is not remotely the same as in real life. The end result of that is that there is no real need for democracy to establish legitimacy because the consequence of a failed leadership is not actually all that interesting. In part this is because there is very limited power.

A guild leadership cannot imprison you. It can’t take your stuff. It can’t injure, torture, or kill you. And if it does anything you dislike outside those bounds (like demand your stuff, ghost you out of events, or be cruel to you verbally) you can leave. So even the game mechanical power that is held over you (like inviting you to raids, determining what loot you can get, removing your ability to invite/kick members) is transient. You can always go somewhere else. This is something that a lot of guild leadership has not embraced: the incredible weakness of their position.

Things that increase the power of a guild leadership are social and organizational and not game mechanical then.

So if you have a guild that is regularly running large raids (which are a substantial organizational challenge) then being allowed in that raid is a desirable thing that can be withdrawn. So that’s a real power over a subset of the membership. Finding another guild that is achieving the same things is not as easy as just finding another guild. But it’s not all that hard either, and so this power is not as strong as we sometimes imagine. The mechanical power here is in the distribution of loot and is restricted to raid behaviour. And you can get what you want elsewhere.

If you have a guild that creates a comfortable, welcoming, and safe social environment in some ways you have even more power since that is somewhat more rare than a solid raiding behaviour. This develops some genuine loyalty (rather than the material loyalty that raiding offers — if someone offers you more, absent any social element, you of course take it) that has some durability. You come to like the people you are playing with and you want to continue associating with them. And the mechanical power a guild has here is the threat of ostracization: you can be kicked from the guild and therefore its social space (chat window, discord server, and so on). But again, you can get what you want elsewhere. But it can be much harder to find a safe friendly and active social environment than a raiding environment that delivers loot.

So a guild controls weakly access to loot. It controls strongly the social environment.

fact 1A successful guild then has to be competitive in raid management (if that’s your schtick) but there are potentially more gains to be had by excelling at social management. Of course there are people who don’t care about the social environment, but because of the very limited power a guild has through loot control alone, these players will move between guilds at will anyway. There is nothing you can do to keep them that someone else can’t do as well or better. The people who are likely to stick, are going to stick because of other reasons. And those are the people you want to stick anyway.

This also means that the work of the guild members to expand a guild is social work. Not just the leadership, but the whole guild. People have to prefer being in your guild even if it’s less attractive for loot generation than another guild (because that is certainly the case) and the only attraction there is social. That also means that the membership that does not raid (and therefore does not impact loot availability) is at least as important as the membership that does. A guild that leverages their social power necessarily attends to its whole membership.

It is easy to forget the social element when you are concentrating on raiding. But that is where your core is and if you reflect on your time in game (what you find fun, who you interact with, what you say and do that’s not raiding) you’ll see that that is true.

Any competent player can get into a raid. Not everyone can find a home.


Okay so now we can talk about delta-v (∆v from now on because it looks cool) in a larger context. We can see from the last post that the thing that really matters in space travel is how much you can change your velocity before you run out of gas. And I’ve talked previously about orbital mechanics. Let’s tie these together. First a diagram I have lifted from a much more detailed article about the topic at Wikipedia:


This is a map of the solar system from Earth to Mars assuming you are travelling using orbital transfers — that is, you don’t care how long it takes and your plan is to burn just enough to enter the orbit of your target eventually. Exactly which way you point and how long you travel depends on many factors that are largely out of your control — at a given time with a given rocket you have essentially one choice.

The numbers on that map are not distances but rather costs in ∆v. And this is why ∆v is the critical resource both tactically and strategically in Diaspora Anabasis: it’s the only resource that matters for planning. Everything else is roughly fixed. Everything you might do to influence travel is going to boil down to changing your ∆v resource or cost.

So to get from the surface of the earth to Low Earth Orbit (LEO) you need to go 9.3 kilometers per second faster than when you started. Soak that in. Notice that almost every other transfer is somewhere between cheaper and vastly cheaper. This is why starting your trip on a planet is so incredibly expensive and why space and low-gravity-planetoid bases are essential to industrialized (and certainly private) space travel: this is an unnecessary expense that dominates everything.

If you have a space craft with 11km/s ∆v in resources, you can reach orbit and sit there. If you built the same ship in orbit, however, you could go to Mars with resources to spare. LEO is 2km away. Mars at its closest is 56,000,000km away. It’s 20 million times more efficient to travel with orbital transfers from Earth orbit than it is to orbit the Earth. When people talk about how hard it is to go to Mars and how we so handily went to the moon remember that: those Mercury and Gemini project orbits were actually the very hardest part of the whole endeavour. Everything after that is vastly simpler.

Now what if you don’t use orbital transfers? What if you want to spend less than 18 months to go to Mars? Well, you spend more ∆v. You can speed up any orbital transfer by burning harder at the start and burning again at the end to slow down. It changes the path of the transfer substantially — you’ll get there faster because you’re going faster but also because you’ll take a physically shorter path — your lazy elliptical arc will straighten as you dump reaction mass into the fire. But it costs twice as much because you have to slow down at the end.

You can think of an orbital transfer as basically matching courses with your destination (since planets are moving too). Imagine you want to catch up with a skier further down the slope than you. You can dig in the poles a little so you’re going faster and take an arcing path down the hill so that you slowly catch up, with friction equalizing your speed at intercept. It’s a lot of calculation and might need a little correction and it’s not the fastest path but it takes very little energy. That’s the orbital intercept.

Or you can drive on your snowmobile straight at your target. You’ll have to correct continuously as they move but you will arrive much sooner. You’ll also have to figure out how to slow down or you won’t be matching courses at all. That’s a “hyperbolic” intercept.

The other interesting thing on that map is the “aerobrake”. This is a way to steal ∆v from planets with an atmosphere: you can use that friction to slow down. We know that slowing down is just ∆v spent pointing backwards. So friction is free ∆v for slowing down! In the last post we talked about slingshotting, which steals ∆v from planets for speeding up. So the natural universe provides a landscape that can lighten the load and this is where strategic play will happen: we have a determination problem in that the math tightly constrains exactly how much ∆v a maneuver costs and you ship defines how much you have — so where are the player choices? What knobs can you turn to defy (rely manipulate) the math? The natural environment provides two.

We’ll talk about how the artificial environment can help next time.

moving space ships

Let’s say we have a space ship and it’s moving at some velocity. It’s not accelerating — its drives are off — it’s just drifting. There is nothing to slow it down in space (no air resistance or other interesting friction sources) and nothing to speed it up. There’s no reason for it to change direction. It’s just going to keep going at this speed in this direction forever. For simplicity we’ll use units of meters per second and consider time in 1 second increments.

We can represent this situation like so:

It just goes ON like this.

On the right is our space ship and on the left is a vector indicating its velocity. In one second, the ship will be at the end of the arrow: its length indicates how far the ship will move in our 1 second tick. It’s predicting  the future for our space ship. This will go on forever.

Now if we want to turn, we can’t just steer — there’s no surface to get traction on, no wheels to redirect our momentum. The only tools we have are rotation and thrust. So that’s what we do. We rotate and we turn on the drive for a while, adding more velocity which we represent as a second vector in the direction of our burn. We can use the vector to find out where we’ll be next: we add a vector to the end of the existing one but at the angle of our burn.

I want to turn left 40 degrees so let’s just rotate 40 degrees and burn, right?

So where will we be after our next tick? Well the trick with vectors is you add them nose to tail, preserving the angles, and then find the hypotenuse (sticking two vectors together gives you two sides of a triangle, and your new vector is the missing side of it!)

Imagine our little space ship travelling along that new line forever.


And we’ll see that with that little 40-odd degree turn and burn (adding velocity!) our new vector has us starting to turn to the left. But we are also going faster than before! And we’re not pointing in the direction we’re travelling. This, in my opinion, summarizes a great deal of what’s weird about travelling in space compared to a road vehicle — you can only add velocity, the direction you’re pointing in determines the direction of acceleration and nothing else, and you need to spend an awful lot of fuel to make an interesting change of direction. Let’s try that turn again but much more sharply.

Burn baby burn!

We’re really cranking the wheel over here! The same rules for adding vectors apply of course so we get a final vector of:

Again, we should imagine little triangle space ship forever moving in the direction of the arrow, at a speed indicated by the arrow’s length, and oriented at a sharp angle to the direction of travel. Forever.

Well that’s a tighter turn! Notice a few things. We’re totally pointing away from our direction of travel for one. For another, our vector is shorter: we’ve managed to slow down by adding velocity in a direction that partially opposes our initial vector. So now we know that the only way to slow down is the same as everything else in space travel: add velocity.

This is why in the latest rev of Diaspora we only track a space craft’s “delta-v” or its total ability to change its velocity. Everything about how it moves, how fast it moves, and where it goes depends on this value. It’s how you start, how you steer, and how you stop. And, when you’re out, you just follow that vector forever.

Well surely not forever. What if there’s a planet in the way? I’m glad you asked. Same rules.

So when you travel near another significant mass, it continuously adds a vector for you, whether you accelerate or not. So let’s say we’re passing by a planet. We have our existing vector but we also add a new one that points to the center of the mass and has a size (magnitude, we say) related to the total mass. Planets add pretty big vectors.

We just wanted to fly by this featureless planet but apparently the universe does not allow such things. Note that it’s only by happenstance that the gravitational vector touches the planet. It could be any length depending only on the mass of the planet.

And the result is:

Planets are powerful attractors! It’s going to be close.

Wow! Notice a few things here. First, you don’t fall into the planet if you already have a big enough vector. If we had a smaller (or no) vector, we’d splat on the surface. But we fall past it! Precisely choosing altitude and vector is how we go into orbit: we just keep falling forever around the planet. But that’s not what this maneuver is going to do. The other thing to notice is that we are going way way faster than before — we’ve taken a ton of delta-v from the planet itself! Since delta-v is in such short supply, this has to be a useful move! We sometimes call it a slingshot maneuver, and it’s a very common way to get real spacecraft long distances in a relatively short period of time. Let’s look at the next second in this picture.

So now our two vectors are our original vector and the gravitational vector, which points to the center of mass of our planet:

Now we are going to be going around this planet a bit but way too fast to orbit it.

Which gives us a result of:

Zoom! If you do the next iteration yourself you might be surprised at the result.

We are going even faster now! All for free! And in a radically new direction.

Now, reality doesn’t actually progress in one second increments, so to find our actual path of travel we’d need to start looking at smaller increments. Do the vector addition every tenth of a second, every millionth of a second, refining and refining the path. This would be calculus, and we would see our actual path is a smooth curve. But the principle is the same and the result we care about is the same: we can steal velocity from planets.

In space all you can control is the change in your velocity, but you can steal velocity from planets. Another time we’ll talk about stealing negative velocity.

a note on gaming

This post is not about a game. You could game this way — it’s easy to see how you could do that, using counters or miniatures. It’s already been done too — Traveller, Triplanetary, Mayday, and even in 3-dimensional space in Vector-3. It’s not news for gaming. But my game targets people who don’t know the physics and maybe don’t care about it, but need a context to understand the design decisions that are based on physics. I will be leaning heavily into abstraction but you need to understand what you’re abstracting first.

splitting an infinitive

Why not?

Well these days (as opposed to a hundred (good to one sig fig) year period of conservatism around which the language is fluid as hell) that’s maybe not a useful question. We do what we please with English and the language is sort of famous for surviving it. For a long time, however, and currently amongst the sort of pedant that has a strong opinion about Oxford commas, the split infinitive was Not Allowed.

But English is really good for splitting infinitives.

The infinitive form of a verb is its naked form, unconjugated. So in English the infinitive “to go” is conjugated as “she goes, we go, they go, you go”. That infinitive is apparently never allowed to have a word inserted between “to” and “go”. It’s to be treated as though it’s un-fucking-divisible. A single word with a space inside it that apparently acts like a letter.

This is, I think, mostly an effort at linguistic political correctness to avoid drawing attention to the fact that many (maybe most) lesser languages do not have this feature. Their infinitives (aller, for example, en Français) are really one word. Which means they do not have the tonal equivalent of “to boldly go” which delivers a mood distinct (to my ear anyway) from “boldly to go” or, worse, “to go boldly”. It’s perhaps the proscription itself that lends this tone (which totally undermines my argument by making the proscription necessary in order to have the feature) by undermining the formality of the “correct” structures. Kirk in the Star Trek opener is established by his linguistic choice as an everyman who doesn’t give a rat’s ass about ancient style guides nor, by extension, Robert’s Rules of Order. We know in our viscera before we even see him that he’s a hero we get to aspire to be. He shirked his way through college and the academy (which later we find out is true). He must have.

And some infinitive busting structures don’t even have correct variants. Consider “I’m going to fucking shoot you in the face.” It’s distinct from “I’m going to shoot you in the fucking face” in that the rude word modifies face instead of shoot. And obvious you can’t say “I’m going fucking to shoot you in the face.” Then you just get laughed at. You’ve descended below the low bar of lovable rogue to incomprehensible villain. “I’m fucking going to shoot you in the face” is weird acceptable, modifies the wrong word, and seems like a grammatically worse choice than splitting the infinitive even though it’s fine. It’s more of a hipster bandit move; an attempt to get you to argue with their usage so they can produce evidence it’s correct. Before shooting you in the face.

So let me suggest that we need not be polite to our compatriot languages who are stuck with indivisible verbs. Our verbs are naturally divisible and this division begs for modifiers. Every space is a possibility for a slightly different tone. It does not invite confusion but rather establishes the writer’s intent clearly and efficiently. The space in the middle of our infinitives is a tool to be wielded however we like to use tools.

Of course, once we get to this point we have to wonder what the “to” is for anyway. What does “to go” mean, decomposed? What work does the “to” do? In the phrase “I’m going to go” it seems to have more to do with “going” than “go” to my ear. That is, as the sentence proceeds, “I’m going to…” is still sensible — I’m certainly going somewhere and to is a somewhere word. I’m going to the store. I’m going to outer space. I’m going to sleep. The “to” is independent — it doesn’t need a verb at all to be useful.

So rather than knuckle under to linguistic equivalentists who would hobble English in order to put it on equal footing withe French or, heaven forbid, Latin, let’s instead celebrate the feature of the English infinitive. Split it at will. It’s already split.

factions as a template

So I was thinking about how to make a generic faction, like for any game at all, and around the time I was thinking about it Takuma Okada tweeted something similar and pointed at Apocalypse World style moves. This is very smart, obviously: moves are certainly a great way to generically encode what things do without having to address specific system mechanisms because the ref’s moves in AW are not really part of the mechanism, per se. They have only narrative structure, giving the ref permission to make a particular thing happen in the story. They don’t engage dice (though that can obviously cascade on from the move when a player reacts) or remove points or add points. They pivot the story. Well that’s as generic as you ca get, so here’s a faction template. My “methods” are moves.

This is a quick hack. What’s it missing?

Alien space bug faction needs fleshing out.

Faction Name

Start with a description here of the faction. Get flowery. Add a little micro (really micro mind you) fiction maybe. Good place for your illustration. Anything in this spindly typeface should be replaced with your own text. Also the title, unless “Faction Name” is in fact the name of your faction.


This section outlines the things your campaign needs to provide to make this faction work: just because it’s generic doesn’t mean it actually fits anywhere. State these up front so that a potential user can quickly disqualify it if it’s inappropriate.


What terrain does the faction need to make work? Where are they headquartered? Robin Hood needs a forest. Rogue Armor Five needs a space station. Deepness Sentinels need a mine in a remote mountain.

Necessary allies

Is there anyone that has to be on their side? Think in general terms — a leader with certain characteristics, a revolutionary organization?

Necessary enemies

Is there anyone that has to be opposed to them? Can the user just plug in any old opposition and it will make sense?

Magic requirements

Are we assuming magic? Are we assuming certain kinds of magic?

Technology requirements

Are we assuming technology? Are we assuming certain levels of technology?


What is the faction trying to accomplish? Keep it generic; the most specific you should get is to reference a “necessary ally” or “necessary enemy”.


What sort of organizations oppose this faction? Keep it generic; the most specific you should get is to reference a “necessary ally” or “necessary enemy”.


How tough is this faction? Can it field armies or only lone assassins? Estimate its membership and its influence.


What kind of strength can the faction bring to bear in a military context?


What kind of strength can the faction bring to bear in terms of bureaucracy, diplomacy, espionage?


What kind of strength can the faction draw from the common people?


How much money or local equivalent can this faction bring to bear on a problem?


Add methods if you need to but at least name and expand on the following ones so that they suit the specific ways and means of the faction. Take into account the Strength parameters to add detail: a militarily weak faction won’t act militarily — they will act to their strengths and protect and disguise their weaknesses. The ref can pull any faction method out and stuff it in the narrative whenever they feel that seems like a swell idea.

Wreck a plan

The faction ruins a player plan by doing something — inadvertantly or otherwise — that undermines their assumptions. Of course, the players won’t know the back entrance is full of Deepness Sentinels on their own mission until the players pry off the sewage grate.

Impede travel

The faction is interrupting a regular travel route, ideally one the players want to use or are expecting news or goods from. This must affect the party to be deployed. It’s not just a news story, it causes the players grief.


The faction tries to recruit the party.

Harm a faction you care about

The faction does some harm to a faction the players are allied with. Maybe the players themselves! Burn down the magic college. Call the cops on the oxygen hoarders.

Be the villain

In a surprise twist, this faction is the real enemy!