The Aurora RPG Engine – Part 13

Postscript 4 – MoS Counting

It’s somewhat thorny to get an idea of an average numerical value for MoS that includes the possibility of failure, since both failure and an MoS of 0 calculate as zero.  However, if we look at mechanics for using MoS either in cumulative or extended tasks, or when it is used to determine damage or an outcome against an opponent, we can calculate some useful guidelines (and get a window on how to use those values in our game).

There are two prime methods to use MoS in this way.  The first is to have a success (MoS of 0) count as 1, plus 1 additional per point of MoS.  So a success with an MoS of 2 would result in a value of 3, whether that be 3 points of damage/effect, or 3 points added to the cumulative pool towards completing a task or achieving an aim.

Using this, we can determine the average MoS expected for a particular dice pool that includes failure:

An alternate way is to re-work the success ladder presented earlier to make an MoS of 0 a little more precarious by making it a Minimal success:

MoS Quality of Result
0 Minimal Success
1 Solid Success
2 Notable Success
3 Brilliant Success
4 Stunning Success
5 Sublime Success
6 Legendary Success

Thus a Minimal success is a case where the character has just, barely, succeeded at the task.  For example:

  • If a character is leaping between buildings, their foot lands right on the edge of the parapet. They made it, but their heart is certainly beating hard now!
  • If this leap was part of a chase, it may cause them to stumble a bit, which, depending on how their quarry rolls, might make them lose a bit of ground.
  • If the character was attempting to haggle for an item, they only manage to get a minor discount.
  • If the character was researching something, they confirm its existence and the overall, general information about the thing, but nothing very detailed.
  • If the character was fixing an engine, they get it running in the nick of time, but it was looking dodgy right up until the last moment!

This is opposed to the next rung up the ladder, where a Solid success is an unambiguous one:  a character lands firmly on the roof beyond the parapet; they achieve a worthy discount; they gain a new piece knowledge that will aid them going forward, or they get things running and are sure that things won’t break again.

The value of making a distinction between Minimal and Solid success is mostly one of RP – it’s to narrate a bare success.  It also helps to make each of the levels above a Solid success more distinct and thus easier for the GM to craft mechanical and narratively appropriate outcomes (and thus also more RP-rich).

Minimal success can also be used to tweak the cumulative/damage mechanics by having the value be equal to the MoS, with the special case that an MoS of 0 counts as a value of ½.  This makes things more elegant and straightforward* to calculate as there’s a more direct line between the MoS and the value (when compared to calculating it as the 1 + MoS method above).

Using this Minimal success method, here is the matrix to determine the average MoS expected for a particular dice pool:

*While keeping track of ½ points of success might seem to add back some inelegance, but as the system is already tracking ½ values for the dice pool the context for ½ points already exists.  Much like modifiers described above, it could be recorded using boxes, where a ½ result is marked by placing a single slash in the box and a full point is marked either with an X in the box or by completely filling in the box.

← Postscript – Further Probabilities & Hidden Rolls & Discoveries | Index

The Aurora RPG Engine – Part 12 Redux

So… when I first posted this Part 12 about further probabilities and the “amazing niftiness” of Aurora being bidirectional… I goofed.  Embarrassingly so, and doubly embarrassing for someone who has rolled many a D&D character under good ol’ 4d6 drop lowest.  I very much led myself astray, and I think it was because I became heavily enamoured with the idea/hope that the system was bidirectional, which led me to not examine my probability assumptions.  Mea culpa.

Having finally realized my error, I’ve gone back and crunched the numbers.  Here are the proper, actual, honest, expanding probabilities tables, hidden rolls, and discoveries.

Postscript 2 – Further Probabilities

First, the possibilities for each MoS:

Then the chances of getting at least MoS of X:

Here’s the average MoS expected on a success (if you succeed, this is the average MoS you can expect):

Postscript 3 – Hidden Rolls and Discoveries

Unfortunately, as the above shows, the system is not, in fact, bidirectional.  But some number crunching can get us a little bit of the way there, at least in equivalency.  Here’s a re-written version:

Typically, the difficulty of a task is handled by adjusting the base dice pool.  This allows the player to viscerally feel their chances and properly size up the situation, thus letting them make appropriate choices (and fully RP it out).  However, there are certain instances where it might be more desirable to not “give away” the difficulty of a task to the player and to have them roll blind.  In certain campaign and genre styles – such as one where the characters are expected to be over their heads or one where it is a grim and failure-heavy milieu – this may apply to most of the tests/rolls.  For others, this may be saved for more uncommon circumstances where the level of tension is heightened by explicitly being uncertain and not in the know.

Blind rolling can also be useful for areas like perception, discerning realities, intuition, investigations, and similar, where the GM may not want to tip their hand that something is there (by specifying there is a penalty).  It can be used such that the overall margin of success determines the amount or exactness of the information gained or discovered.  Star Trek Adventures does a version of this for many types of searching, sensor, and similar tests, giving a basic amount of information on a success and allowing the player to spend Momentum (their version of MoS) to give additional and more exacting details and information.  Under Aurora terms, an MoS of 0 would give the base level of information, while an MoS of 1 would reveal something more obscure and an MoS of 3 might divulge everything.

To set an equivalent MoS for a Blind Test, use the following equivalency table:

(Note that these equivalency values change and drop if a character’s dice pool is very high when compared to the MoS required.  For example, a character who has a pool of 7½d and needs an MoS of 3 only actually suffers an equivalent difficulty of -1d instead of the -2d indicated on the chart above.  This is unlikely to have a major impact in most scenarios, but if a character’s pool is large and gauging against a low MoS equivalency, consider stepping up the required MoS by one if you’re finding characters succeeding more often than expected and appropriate for the campaign.)

Postscript – Breaking the Core Mechanic | Index | Postscript – MoS Counting

Gaming Thursday: Cortex Clocks and Complication Mods

Two quick Cortex Prime mods tonight that we’ve used in our game and liked for what they bring to the table.  Enjoy!

Complication Mod: Cortex Clocks

A Clock is a mechanic employed in a number of recent RPGs (most notably in Forged in the Dark-based games). It is simply a method to track either progress towards overcoming an obstacle or, more importantly here, the approach and/or fruition of impending trouble.

This Cortex Mod is a new way to generate a Complication. Rather than being something that affects the characters right now (by being included in opposition pools when appropriate), it is instead a countdown to something occurring on the level of the narrative. A classic example is a clock that represents “The guards have been discovered an intruder” during an infiltration-type scenario. Every little snag along the way, represented by a Complication, further alerts the guards that something is amiss. This could be marks on the door from a lockpicking session, noise made while darting down a hallway, a piece of equipment that fell out of a pouch, and so on.

Clocks in Cortex forgo the typical drawing of the clock and instead use dice in a similar manner to Complications. When the Clock is created, place the die (the larger in stature, the better!) in the centre of the table. As the Clock ticks upward (as described below), replace the die with the newer size. Once the Clock is stepped up beyond d12 the peril comes home to roost for the characters. The situation has changed, and the characters now have to deal with it. To follow the example above, the facility might go on lockdown, providing bonus dice to opposition pools, and/or increasing the number of tests required, and/or having to deal with guards looking for them, and/or shutting down certain options to the characters, and/or could also prevent a clean getaway and thus lead to further challenges (and RP opportunity!) in the coming days.

There are two main ways to handle ticking up the Clock:

Method 1 – Complication Escalation. This follows the standard Cortex method for increasing a Complication, based on the test’s effect die. If the die size is less than or equal to the current Clock level, the clock increments by one; if the die size is greater higher then the Clock level is set to that die size. As such, this Clock can shift from manageable to a crisis in a single test.

Method 2 – Incremental Escalation. This replicates the behaviour of traditional clock mechanics. Under this style, when a Clock is first activated, it begins at a particular die value and incrementally steps up one die at a time for every additional Complication (irrespective of the Effect Die). In this way, the total “length” of the Clock is known, and the peril ratchets up in a more predictable manner.

Choose the starting die based on how many ‘ticks’ needed to fill the Clock:

d4      –     6

d6      –     5

d8      –     4

d10    –    3

d12    –    2

(An 8-tick Clock could be created by putting down two d8s; both must be stepped up beyond d12 for the Clock to be complete.)

Two additional options to this style of Clock:

When the Clock is ticked up, if the test was a Botch then step up the die twice.

On a Heroic Success, a character may spend 1 PP to step down the Clock die.

Complication Mod: Stepping Down an Asset

Rather than adding or stepping up a traditional Complication, this Mod allows the option to instead step down an Asset or Personal Asset. This could represent the opponent negating a scene-created Asset (whether Test or PP created), damage to a physical signature asset, the weakening of bonds, character doubt, depleted powers, overuse of a resource, and the like.

Step down the Asset based on the Effect Die:

d4     –      1 Step

d6     –      1 Step

d8      –     2 Steps

d10    –    3 Steps

d12    –    4 Steps

If an Asset is stepped down below a d6, it is removed from play. (The GM may determine if it can be recreated, and if so, whether it becomes more difficult to do so.)

If a Signature Asset is stepped down below a d6, it is temporarily shut down. The character loses access to it until it is recovered.

As with standard Complications, how a stepped down Asset or Signature Asset recovers depends on the narrative and situation at hand. Some may recover automatically in increments over time, others may require characters to perform certain actions and/or may require a Test. For example, a damaged piece of equipment may be able to be repaired with a Test, or be automatically restored to full if the character can return to their lab (with any corresponding narrative implications for doing so).

[[Sidebar: Whether this is more or less harsh than a regular complication I’m not sure of yet. My initial thought is that it might be less harsh (rolling a d6 instead of a d8 rather than having test difficulties gain an entire additional d6, for example), but at the same time I don’t think that’s a problem. It can be very appropriate in the narrative and flavourful for the character, is easier to administer than adding another die to an opposition pool, and per my musings on Complications a few months ago given that Hitches are plentiful another option that feels different could well be welcomed, even if its drawbacks are technically mechanically less.]]

Gaming Thursday – Cortex of FATE

As mentioned last week, I’ve been digging through the Cortex Prime ruleset.  We’ve been using it in a narrative-forward campaign that was originally conceived and played in the FATE ruleset.  So far it’s been going well, and I’ve discovered a few things that I prefer within Cortex.  For starters, nearly every test in Cortex involves/includes one of the character’s Distinction in the pool, whereas in FATE a character’s Aspects (essentially the same as a Distinction) only come into play if you spend a Fate Point.  While the latter might be more dramatically highlighting, outside of those Point spends there’s less to distinguish one character’s skill or approach or flavour from another.  By including a Distinction with every test, however, a character’s flair and flavour is likewise included and reinforced.  Another neat bit is how, by leveraging Cortex’s unusual die mechanics, there are several slick ways that can be used to resolve different kinds challenges or encounters or situations.  There’s a streamlined way to run obstacles or swarms or large-scale events, a way to craft interesting one-on-one contests, and another that allows for tracked action/reaction encounters.  Each unique yet still tied to the same mechanics, and each of them are evocative and allow for plenty of player creativity that highlights a character’s schtick and personality.  Lastly (for this post), there are slightly more reminders and perhaps incentive to invoke against yourself and therefore keep the meta currency economy flowing.*

Even with all the neat stuff in Cortex, however, there are some features of FATE that I do find missing within the base Cortex Prime ruleset, especially around the larger and more impactful narrative-altering use of Aspects and Fate Point spends.  Hmmm… why not take those ideas/concepts and incorporate them into the Cortex experience?

And lo, the Cortex of FATE mod was born!

To be clear, this is not an attempt to model or reproduce FATE within Cortex Prime – even using this mod the game still plays and feels like Cortex.  Instead, the additions are intended to enhance the narrative oomph of a campaign, primarily by adding additional uses for Distinctions and Plot Points and by porting over Approaches as a new Prime Set.  All in all, the goal is to entice greater storytelling opportunities.

We’ve been playtesting these mods in our Broken Lands campaign and thus far they’ve been working great.  If this piques your interest check it out, and I hope they help fuel wondrous and engaging stories for all those around your table.

* To be complete here, let me mention that I find there are also some downsides with the interesting dice mechanics.  Beyond the one I already spoke of last week, the principal issue is that in building a pool mechanic that both a) uses so many different die types as well as b) adding only two of them together to determine the result, it becomes quite difficult to get a grasp of the probabilities and outcomes.  This can be especially acute for the GM to set difficulties; if the base is 2d8 difficulty, how much harder does it make it if you add a d6 to the mix?  Or for players, is it better to go with a pool of 1d6|2d8|1d10, or a pool of 1d6|4d8?  With the d10, the former certainly allows for potentially greater success, both in a higher total as well as in choice of effect die, but will the latter, with its higher number of dice, equate to a higher average roll and thus higher chance of at least marginal success?  It gets worse when you realize that both the GM and the Player is rolling each time, with no static target numbers, and each with pools of dice that might be different each time… it will take a while to get a feel for “power levels”.

Gaming Thrusday: Cortex Complications

As I noted a little while back, our group has delved into the Cortex Prime ruleset for our current campaign.  I’d tried out Cortex a bit in Firefly, but this is my first deep foray into the system and thus far I’m really liking it.  There’s a lot to it that does a good job of facilitating a narrative-heavy style of play, with each character having plenty of latitude to accomplish things in their own way which helps make them feel distinct, interesting, and open for lots of RP.  Good stuff!  And that the first “complete” Cortex Prime RPG has just been released (as opposed to the Cortex Prime rulebook which is a giant toolbox) in the form of Tales of Xadia there’s plenty more chances for people to try out the system, and I’m excited for its spread.

However, there is one aspect of the system that threw us a bit for a loop:  Generally, building a larger pool* is desirable as, obviously, makes it more likely to get a high result and thus achieve success.  Perhaps counterintuitively though, that same larger pool also means more chances to roll a hitch and therefore more chances for a complication.  Thus, the better your chances equally better is your chance to have something detrimental come out of it.  This seemed both weird (in that counterintuitive sense) as well as punishing, and we bumped on it for a while.  However!  In yet another one of those “walking through the house” epiphanies, I got what I was missing to see it in a much more useful light:

  1. Rolling a hitch always removes the die from your pool. However, AND THIS IS THE BIG THING, it is up to the GM whether to ‘activate’ it as a complication, or not.  Not every hitch HAS to be activated into a complication.
  2. IF the GM activates, you get a PP. This is important as it is one of the primary ways to enable and ensure the meta-currency economy.
  3. So if you do get the complication you also get something to help you get out of it if you need to… and if you don’t, excellent! You get to save that meta currency for extra awesomeness later.
  4. In addition, if the GM creates a complication based on the hitch, then, in general, that complication should LAST NO MORE THAN THE SCENE. It mucks things up in the moment, but it isn’t “sticky.” They are a narrative setback that are a niggle only for the moment.  (Lingering and sticky effects should mostly be the result of a failed test or contest or go to the stress track if using that mod.)
  5. (As an aside, if there is a case where it might be good to include a complication as something that lingers, then it can act like a clock, filling up until it triggers something. For example, a hitch on a test to infiltrate a facility could begin a complication called “Compound Alerted”, which might increase the base difficulty of future tests, and if the complication is stepped up above a d12 then compound goes onto lockdown.)
  6. It is also good to remember that complications don’t necessarily apply on every test going forward, only on tests where the complication would apply or have an impact. This can entice players to find alternate and creative ways to work around the complication, leading to more drama and dramatic action.
  7. Overall, the intention behind this mechanic might be to “balance” large pools somewhat. In other words, if you can build up a big pool the increased chance of hitches helps keep it in check and keeps things narratively interesting.
  8. I think a good hitch activation rate might be between 1/3 to 1/2 of the time. This allows for the narrative drama without it becoming a frustration for the player or, worse, feeling feel like punishment for when your character is really good at something (ie, when you have a tonne of dice in your pool).  It also alleviates the GM from having to continually come up with interesting complications.
  9. (For clock-like hitches it might be OK to activate them more often…)
  10. It’s also worth thinking about when to step up an existing complication, and when to create a new one. Roughly, I think stepping up only once per scene (which keeps it from potentially becoming overwhelming) is a good baseline before activating a new complication.

As an additional bit, and I don’t know if it’s explicit in the Cortex Prime rules or not, but I would allow the players the choice of whether to include an opponent’s complications or stress dice in their pool or not.  If they are forced to, and they hitch on that die, then once again it can elicit frustration and annoyance.  Alternately, or in conjunction, as a GM I’d have a light touch on activating complications that arise from including an opponent’s complication or stress dice in the player pool.

With all of the above in mind now this quirk of the system sticks less in my craw.  It becomes an opportunity for something, and like so much else at the table it is an opening for conversation.  What would be cool here?   What would make for the “best” story?  What’s dramatically appropriate?  Out of that will come whether or not to create a complication and, if so, what complication to create, all in service of the action and drama and story.


* Briefly, if you’re not familiar with the system, the base mechanic is to build a pool of dice (of differing sizes depending on what’s going into the pool), roll, and keep two to determine your total.  Any die that rolls a 1 is not only removed from the pool but, crucially, allows the GM to create a complication for the character.  These complications come with their own die rating and actively hinder the character.

Wonder Wednesday

There’s something about these AI-generated pieces of art that are quite neat…. certainly not photorealistic by any stretch of the imagination, but certainly images that do indeed stretch the imagination.  They’re very much like abstract concept art, which I think is perfect to use for tabletop RPG games to set a mood, feel, tone, or theme.  They’re evocative and let the player’s imaginations run free, which can be even stronger than a full polished piece.  Plus, they don’t tie you or the players to something so specific it creates an inadvertent straight jacket.

Check out more examples at this forum thread here, or try it out yourself!  (Click on “Start Creating” at the upper right to do it on the website.)

Gaming Thursday: Broken Lands

My gaming group and I are getting ready to return to the Broken Lands, a campaign some of us had started many years ago that unfortunately ended soon thereafter as the main GM and another player had drop out.  Back then we ran the campaign in FATE, but this time I’m shifting us to using Cortex Prime with some hacks to bring a few more FATE-like elements into the game.

Also back then I, no surprise, made a character sheet for our game.  This time around we’ll likely be keeping most of our records in our shared OneNote instead, especially since we’ll be mostly remotely gaming… But, do you think THAT would keep my completely non-obsessive and totally healthy character sheet design mania at bay?

Of course not!  What fun would that be?  And so:

I’d probably tweak it some more, but given the uncertainty as to how much use it would actually get, this is probably a good place to leave it for the moment.

(As an aside, I am a bit enamoured with Cortex Prime right now, there’s a bunch of nifty aspects to it, and it is one heck of a wide and extensive toolbox.   I’m looking forward to seeing how it plays out at the table.)

Gaming Thursday: The Troubleshooters Aurora Casefiles

The Troubleshooters RPG is a game based on the action, adventure, and mystery genre of Franco-Belgian graphic novels (aka bandes dessinées), especially those of Tintin and Spirou & Fantasio.  Now, if you’re like me, just that tagline is enough to excite you!  And if it does, you’ll be equally excited to know that the game is now out for all.  It’s a definite beaut, well put together with art and layout that do a great job to evoke the genre.  Even better, so do its rules, with the core system being solid enough and with some nice mechanical nods that provide support towards playing and creating those types of stories we love.

Having backed the Kickstarter, I received the PDF a few months ago and have greatly enjoyed diving into it.  And while I have no major issues with the base system, I immediately began wondering how it might play using the Aurora RPG Engine.

I think you can see where this is going…

Enter: The Aurora Casefiles!  A conversion that aims to bring the advantages of both Aurora’s dice mechanics as well as its narrative tools to the world of the Troubleshooters.   This is not attempting to design the game from the ground up; rather it strictly keeps as much of the core Troubleshooters rules and all its nifty subsystems (such as dice flipping, karma, dice challenges, duels, story points, and more) intact.  It’s the best of both worlds!

Snag your copy here (and the Aurora Engine document if you haven’t already), pack your camera, bring along your favourite white dog, a few companions, and let the adventure begin…

(Note that this conversion document only contains the bits that are necessary to modify the base Troubleshooters core rules to use the resolution mechanics of the Aurora Engine.  As such, you will need a copy of the core Troubleshooters RPG, which you can get direct from Helmgast here or also from