BMDev 4: Wargame Combat Design

From the present moment onwards, it is important to see and understand TTRPGs as wargames in every sense. If the gameworld has the opportunity for conflict and the requisite freedom of action inherent to TTRPGs, we will necessarily encounter large conflicts. Though BMD is a game explicitly focused on humans vs. aliens warfare, this principle applies even to TTRPGs focused on other aspects.

From a designer’s standpoint, it is our role to acknowledge this and to support players with procedures and rules that allow them to explore this idea efficiently. Let’s examine the design philosophy behind this endeavor by seeing how BMD tackles its combat design.

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The Wages of Freedom

Players in a TTRPG have the capability of creating an unfathomable number and variety of situations. Outcomes in most of these situations are clear. Players climb to the top of a hill to see beyond it; they burn a letter to conceal the message it held—no one questions the implied resolutions in these actions.

But the “drawback” of creative freedom is that many circumstances will be complex enough to create explicit questions that require something more. This is where the rules come into play—when it is not “obvious” what should be done.

Combat resolution is consistently a heavy hitter when it comes to procedures and rules in TTRPGs, largely owing to wargames heritage. BMD is certainly a combat-oriented game, and its designs are a good launching point for an outline of wargames design.

BMD is aimed at supporting theater-of-the-mind to the highest degree possible in every circumstance. However, there are times when we all want more granularity and a more concrete sense of what happened. In some cases, this is just for fun. A more pointed concern is that the rules enable players to answer questions more carefully if it is deemed necessary. This is accomplished by creating a set of gameplay constructs that players can map onto their situation—whether that is a simple mental model or a full-blown tabletop play-by-play.

But how do we source these constructs? When designing elements of a game, how do we know what ideas to include and what to handwave or ignore?

The Onion Philosophy of Combat Resolution

The defense industry is a bottomless well of amusing, puzzling, and incomprehensible charts and infographics. Though much maligned, the “Integrated Survivability Onion” graphic is a brilliant example of when things accidentally go right.

This poses the problem of surviving an attack as a hierarchy of defense concepts ordered by effectiveness.

1. Don’t be seen

2. Don’t be acquired

3. Don’t be hit

4. Don’t be penetrated

5. Don’t be killed

We can reverse these statements into a line of complementary questions from an attacker’s point of view.

1. Can I see them?

2. Can I acquire them?

3. Can I hit them?

4. Can a hit overcome their defenses?

5. Can overcoming their defenses kill them?

This is the perfect ordering of considerations for building a simulationist-oriented combat system. It addresses the central ideas (general enough to apply to any game with combat) in such a way that a “No” answer represents a stopping point and a release of tension, signaling that the players involved can move on from the attack. But a string of “Yes” answers is something the players can plan and plot toward. Each “Yes” escalates play into a new threat level, with death looming at the final step.

1. Can I see them?

This question is general enough that there are many possible interpretations to its meaning. This makes it easy to apply to any game. In BMD, we actually use two different interpretations of this question to inform the game’s design.

a. Surprise

We first consider the awareness gap between Forces present—is one side unaware of the other? I particularly like how this consideration highlights the distinction between gameplay and rules. There are few rules required to say “you can’t attack those targets because you have no idea they exist,” but a great library of gameplay will naturally revolve around achieving this outcome.

When Encounters¹ are being set up, the most impactful factors are the initiative and deployment advantages. In many cases, a Response roll is required to determine which side has one or both of these advantages. But if players successfully orchestrate an ambush on an enemy Force, there would be no need to roll!

In concrete terms, having deployment advantage means our side deploys no units until the opposing side has deployed every unit—total positional dominance. Having initiative advantage means our side gets to go through a whole round of actions before the opposing side ever gets to act. The combination of these two advantages shows the raw power of opposing Forces being unaware of our Force.

b. Line of Sight

In more typical scenarios, the question “Can I see them?” is asking about the terrain and circumstantial visibility. Here we get into obstructions, light and heavy terrain, and other LOS issues.

Summary of basic LOS configurations in BMD

In BMD, we provide a few simple LOS concepts that players can map onto any situation. Intervening obstructions block LOS and provide a clear “No.” Obstructions cannot be occupied like Light or Heavy terrain. Intervening Light terrain does not affect LOS (unless the line would be drawn through multiple Light terrain instances), whereas Heavy terrain blocks LOS completely just like an obstruction.

If a unit occupies a piece of terrain, that terrain no longer counts against drawing LOS to that unit; the unit instead gets cover if the terrain would ordinarily block LOS.

There is equipment which can overcome many of these limitations, but this is the starting point.

2. Can I acquire them?

If we can see a bird flying far off in the distance, could we theoretically hit it with a baseball bat? A rock? A bullet? A guided missile?

Target acquisition is more than just knowing a target is in the area—it is about having sufficient knowledge of the target so that our weapons system can function effectively. If our weapons system is a club and our information is “the target is right next to us,” that’s a suitable match. A sling vs. a distant fighter jet is another story.

Range

In BMD, the first consideration for acquisition is a weapon’s Range score. If a proposed target is a distance over 2 × Range, any attack automatically misses—simple!

Targeting Systems

Complex weaponry like orbital lasers or missile launchers don’t have an operator to aim them and thus require automated targeting systems. These platforms have a Range score and operate on the same Range-based principle for automatic misses. But any of their attacks will also automatically miss if the weapon platform’s targeting system is destroyed or disabled.

3. Can I hit them?

After identifying and acquiring a target, this next question addresses the more quantitative aspects of an attack. In BMD, there is an Accuracy test (using D10 + Accuracy) for every kind of attack².

In order to hit a target, an attacking figure needs to get a 10 or better (10+) on this test. Improving the Accuracy score of the operator (or the targeting system) will improve the chance to hit.

There are two common complications: Evasion and terrain. If the target unit has an Evasion score (as a special ability from training, stealth gear etc.), the attacker’s Accuracy will be reduced by that amount. Intervening terrain causes an Accuracy penalty of -1, though advanced targeting equipment can mitigate this. Occupied terrain counts as intervening terrain for this purpose.

4. Can a hit overcome their defenses?

Every attack in BMD has an associated Coverage (COV) score that is unleashed when the attacker manages a hit. An attack’s Coverage represents the ease of applying meaningful damage during the typical 1-minute round. A weapon that has COV 3 rolls three dice, and a weapon with COV 10 rolls ten dice—an important score!

Visual summary of BMD’s attack mechanics

These Coverage dice are rolled as a pool, looking for results of 10+ again—this time using the weapon’s Lethality score as a bonus. Any successes are tallied and counted as Damage at the end. The goal for an attack is always to achieve as much Damage as possible. The target’s ability to deal with Damage is very limited—thus piling it high is the path to victory.

a. Weapon Platforms

We can improve Damage output by improving the weapon—that’s the source of the Lethality and Coverage scores. In BMD, players have ready access to basic weapons and equipment left over from a previous failed Terran polity. Low-rank commanders will want to focus on gaining improved equipment at the beginning. However, there is nothing like a “gear treadmill” producing weapons with ever-increasing scores.