Today we’re continuing our series about combat geometry with our resident Sins designer, Conor Harris (Sovereign Echo).
Missiles are a unique weapon in Sins of a Solar Empire 2. They are closer to a unit in many respects, with distinct interactions at both the physics simulation and mathematical damage layers of the combat system.
As with the previous Combat Geometry dev diary, we will begin with an obvious yet an important statement:
Missiles must strike their target in order to deal damage.
Against a static and defenseless target, missiles are guaranteed to strike and deal damage, but there are a number of ways that a missile can fail to strike its target:
Point Defense shoots the missile down early.
The movement of the target causes it to evade the missile.
The missile runs out of fuel and self-destructs.
Point Defense (PD):
PD weapons are light weapons designed to hit small and fast targets like missiles. As one of only two weapon types able to even target missiles (the other being Fighter weapons), PD weaponry provides a unique defense mechanism - it can destroy an incoming missile outright. A destroyed missile never strikes its target, and so never deals damage.
Evasion:
Evading a missile is extremely difficult under most circumstances, as the missiles in Sins 2 are programmed to follow very efficient pursuit courses. However, not all missiles are made with maneuverability in mind, and small, agile targets like Corvettes engaged in an orbit attack pattern will often evade a missile for a long time, or even entirely.
Fuel:
Missiles have limited fuel and cannot keep pursuing a target forever. If a target can evade or fly directly away from a missile for long enough, the missile may run out of fuel, at which point it self-destructs harmlessly. All missiles have more than enough fuel to reach their maximum firing range under normal conditions - this isn’t something the attacker should be expected to worry about most of the time. It primarily comes into play when firing missiles at a retreating enemy, especially if the enemy is moving quickly.
The Geometry:
Successfully defending against missiles is all about geometry and velocity. The longer a missile is within the range and firing arc of PD weaponry, the more time the PD weapon has to attack the missile, the more likely the missile is to be destroyed.
This has a few consequences:
A faster missile will be exposed to PD for a shorter time, and therefore will be safer.
PD units can maximize firing time by positioning themselves at the midpoint between the missile launcher and the target of the missiles.
Conversely, PD units hiding right next to the thing they are defending cut their effective engagement time in half.
Any ability that can slow missiles down in flight, like Magnetic Singularity on the Dunov or the Vasari Gravity Anchor item, greatly increases the effectiveness of nearby point defense.
Range is a key stat to improve for PD weaponry - more range means missiles spend more time vulnerable to interception.
Notably, missiles also take time to reach their maximum speed after firing, leaving them slightly more vulnerable as they leave the tube. Because of this, aggressive positioning by PD equipped units can generate better interception rates.
Saturation Tactics:
The geometry of missile interception can have advantages for the missiles as well. Missiles fired in large, coordinated salvos all pass through the danger zone of PD weapons at the same time. In practice, this means that PD only has approximately the same time to intercept as if it was engaging a single missile.
Point Defense grids can also be significantly degraded in effectiveness through the use of other strike craft - TEC and Vasari bombers both also fire missiles, and in fairly large quantities, while themselves being a priority target for PD as well. Every shot fired at a bomber missile or a strike craft is one that could have been fired at a more dangerous incoming missile.
Armored Missiles:
As well as saturation attacks, it is also possible to use certain missiles, like the heavily armored Breaker Missile fired by an ability on the Javelis, to draw PD fire and otherwise augment a salvo. With careful timing, this can result in many more missiles getting past PD than otherwise would have, dealing significant damage to the target.
Missiles make up for all their complexity and many potential failure points by having some of the best combinations of damage and pierce of any weapon.