Skip to main content

Simulationist Pitfalls: The Mixed Fidelity Ruse

Articles like this "Clunky Mechanics in 5E", "Flank You Very Much: Tactical Play in D&D", and others, start to address tactical, aka simulationist concerns in the new D&D Next / D&D 5e ruleset.  One particular rule, flanking, has been a controversial subject since the beginning.  I'm going to pick on this particular example to explore an important aspect of simulation, namely fidelity.  Simulation is one of the few areas I would consider myself an expert in, so I think this discussion is warranted.

Simulation is the representation of a specific system using a series of mathematical relationships.  Simulation allows us to predict the outcome of the system without having to have a real system.  Fidelity is the level of detail that we include in a simulation.  Up to a point, fidelity can decrease the uncertainty in the prediction we make.  At some point, however, too much detail in a simulation simply clouds the uncertainty of the result with all of the uncertainty in the parameters used as inputs to the simulation.  Picking the right fidelity is usually key when putting together any kind of simulation so the right answer can be attained with the least amount of resources of computation.

Mixed fidelity is when we simulate certain aspects in great detail while we gloss over the details in other areas.  Mixed fidelity is a danger, because the low fidelity uncertainty can easily swamp out the detailed simulation, resulting in an imbalance of prediction.  The result is a simulation that may not predict anything realistic.

So let's jump back to our example.  Back in D&D 3.5 / Pathfinder we could get a +2 attack bonus for flanking.  However, in both D&D 5 and 3.5/Pathfinder, there is no facing. Without facing, we can now start to get unrealistic scenarios like the following:
Here we have four blue attackers all getting flanking bonus off a single partner, the blue guy in the center.  The reality of the situation is that the blue guy in the center is in serious trouble and not a really good flanking partner.  No worries -- he's also getting a flanking bonus for all 4 of the red guys that can attack him from his 4 blue attackers.  Without facing, it's easy to see that flanking bonus becomes unrealistic.  And why does this happen?  Because we have chosen to include one high fidelity component, i.e. flanking, when we didn't include another element of similar element of fidelity, i.e. facing.

Ultimately, this is what makes rule systems like D&D 5e better.  They have eliminated some of the fidelity that was both overwhelming and unmatched in the rule system.  The new streamlined rules allow for complete segments of rules to be swapped in and out, per the DMG, in order to change the fidelity, while trying to balance the overall fidelity in each approach.  I think GMs need to keep this in mind as they start tinkering with rule systems so they an understand the pitfalls of various changes they may make.  I also think looking at this example illustrated the elegance of D&D 5e and how it has fixed some of the mixed fidelity pitfalls of previous editions.

Comments

Popular posts from this blog

5E Starting Gold and Equipment for Higher Levels

The DMG has a rough recommendation for starting gold and equipment for higher levels, but with my groups running one-shots, we wanted to nail it down to level by level. Here's my DMG-inspired table. Generally I allow equipment to be traded in during character creation for half book value, where applicable. I also, as a GM, offer to make custom magic items for players who can't choose. A list of magical items by rarity can be found here  with stats available in the DMG. I also generally allow players to buy healing potions (2d4+2) for 50gp and greater healing potions for 250gp (4d4+4). PHB items are available at book cost at creation. I do not allow other equipment to be purchased except in game. This is generally based off the "high magic" campaign. Level Starting Gold Starting Equipment / Magic Items 1 - 160gp  OR Standard starting equipment 2 210gp Standard starting equipment 3 285gp Standard starting equipment 4 365gp Standard sta

Rules for Flying Creatures in 5E

I'm not one for just throwing my players willy-nilly into something new without an idea of how it would work.  Flying races are on the horizon for one of my games, so here are my clarifications for flying creatures: A flying creatures requires a minimum space of at least 3 times their height in all directions in order to flight. For example, a 6 ft tall flying creature requires a room to be at least 18 ft in all dimensions before they can fly in it. A flying creature can attempt to grapple a creature.  If the the target or grappler are flying, grapple attempts are at disadvantage. If neither are flying, grapples are per RAW.  The state of flying or walking is determined by the last square you have moved.  To change between walking and/or flying, you must use at least 1 space of movement.  Movement rules per RAW apply (PHB pg 190 "Using Different Speeds") A successful grapple check by a flying creature can allow the flying creature to potentially carry the creature

Exploiting Weakness in D&D 5e: A Guide for the Evil Plotting GM

I wrote a similar article to this on Pathfinder, and though this is a pretty evil topic, it has been of use to a lot of folks out there.  So, now, I think, is the time to start a similar article for D&D 5e.  This will be a living document to be updated with suggestions and more information as I find better methods. In general, 5e is a lot more challenging for a GM, because the classes are reasonably balanced and because the game mechanics don't have a lot of scale over the 20 levels. Here's a general list of things to increase the difficulty for the party: Increase the number of foes and the CR (ignore the book CR system if it isn't offering a challenge) Spells against the PCs low saves.  A high level sleep spell, for example, could take out a party with no elves. Drag out the opportunity for the long rest.  After 2 short rests, the 3rd battle of the day is tough. Hit the most vulnerable PC first. It almost always forces another teammate to take an action to a