The previous three sub-Chapters deal with situations wherein the various combatants all share the same scales of motion. Many combat situations are not so unambiguous. An infantry battle could be going well until the enemy brings in a tank. Soldiers could fire shoulder-mounted missiles at an aircraft. Bombers could be making torpedo runs on capital ships while their escorts duke it out with enemy fighters. In situations wherein combatants from more than one scale of motion are present, combat is considered "mixed-scale" and several special rules apply.
In a mixed-combat situation (sometimes called a "cross-combat" or "cross-scale" situation), the rule is to always use the scale that utilizes the largest spatial increment. This has a negative effect on the movement of any smaller-scale combatants; if the differences in scale are significant enough, smaller-scale combatants may effectively become stationary.
The spatial increments of the varying scales of combat from smallest to largest are as follows:
- Character-scale (Short-Range): 5 meters
- Character-scale (Long-Range): 25 meters
- Land Vehicle-scale: 1 kilometer
- Sea Vehicle-scale: 10 kilometers
- Air Vehicle-scale: 20 kilometers
- Space Vehicle/Capital Ship-scale: 10,000 kilometers**
Space vehicles and capital ships are in a unique situation when it comes to cross-scale combat. Technically, they have the largest spatial scale of any combatant, but the situations in which they could engage a smaller-scale combatant would require them to first enter planetary atmosphere in most cases. In all instances where space vehicles are engaged in cross-scale combat, they should be treated as air vehicles.
In mixed-scale combat, all combatants still determine their Initiative Check values as normal, with one exception: smaller spatial-scale combatants get a +2 Initiative bonus per step smaller than the largest spatial-scale combatant present. Space vehicles/capital ships count as a larger scale than air vehicles in this case (i.e. if an air vehicle was attacking a capital ship, it would get the Initiative bonus) and characters will always use the long-range spatial scale in cross-combat situations. In the event that there are combatants in a situation with multiple scales and terrains, the Initiative bonuses stack up. Take the example a situation wherein a character, a tank, a jet fighter and a capital ship are fighting with one another (not likely, but possible in some cases). In this case, the jet fighter would get +2 by virtue of it being an air vehicle against a capital ship, the tank would get +6 by virtue of it being a land vehicle against a capital ship and the character would get +8 by virtue of it being a character (again at long-range) against a capital ship.
Damage and Scales of Combat
Weapons on larger spatial scales as a rule have a far greater destructive potential than those on smaller spatial scales; a weapon that inflicts one point of damage to a capital ship or vehicle is significantly more powerful than a weapon that inflicts one point of Lethal Damage to a character. For a character to be hit by a weapon designed to damage a vehicle is almost always certain death, while a weapon designed to kill a character may not even dent a vehicle (there are, however, a few very powerful character-scale weapons designed to be used against significantly armored targets and vehicles). When using larger spatial-scale weapons against characters, always assume the weapon does Lethal Damage only.
There is a fixed conversion rate between the character- and vehicle/capital ship-scales of damage. For reference, ten points of Lethal Damage on the character-scale equals one point of damage on the vehicle/capital ship-scales. When converting between the two scales, any decimal remainders from the scale conversion are always rounded up regardless of how small they are. Any conversion between scales should happen after the amount of damage to be inflicted upon a target has been determined, just before it is to be applied. Damage conversion assumes that weapons of different scales are being used - a vehicle that is merely firing off a character-scale weapon at a group of characters would not convert damage to the vehicle-scale first, but a conversion would take place if it was firing on another vehicle instead.
To help offset the inherent greater power of larger spatial-scale combatants, it is assumed they have a harder time targeting any smaller, relatively more nimble combatants. To reflect this, an HD modifier applies in mixed-scale combat situations. This modifier is dependent upon the difference in Size Class between the various combatants. Subtract the Size Class of the smaller combatant from the Size Class of the larger one and add five. The final result is subtracted from the HD of the smaller combatant and added to the HD of the larger combatant. All character-scale combatants will need to subtract eight levels from their Size Class to account for the difference between the character and vehicle/starship Size Class scales (e.g. a Size Class 5 character in combat against a vehicle is considered to be a Vehicle Size Class -3 combatant).
For example, a Dorkathi-class Transport is shooting at an attacking Sabre. The Dorkathi ordinarily has an HD of 38 and a Size Class of 16, while the Sabre ordinarily has an HD of 31 and a Size Class of 10. In this case, the Sabre gains a bonus of eleven to its HD (16-10 = 6, 6 + 5 = 11), bringing its HD down to 20. Conversely, the Dorkathi's HD will increase to 49 when the Sabre makes its inevitable counter-attack.
A target will always take a hit if a critical hit result is rolled regardless of its scale; there are no scale adjustments made to HD for critical hits. Likewise, there are no adjustments for critical misses by a combatant.
Unlike all other forms of weaponry in the game, heavy ordnance shots are not instantaneously resolved. Rather, all heavy ordnance is treated as Size Class 1 space vehicles in their own right, coming into a combat situation upon launch. Launching heavy ordnance requires a successful Ballistics attack roll against the target's BHD; in all cases a lock for any prescribed period must be maintained as with light ordnance. If a critical hit is rolled, the ordnance will do double damage as normal but only after the weapon impacts. Heavy ordnance remains active for a number of rounds equal to its "optimal range". Once launched, heavy ordnance will travel towards its target at the speed indicated in its stats and will hit the target once it enters the same square; it will not turn more than 45 degrees in any given move action. Heavy Ordnance cannot be spoofed but can be targeted by other combatants like any other vehicle. All Heavy Ordnance has HD ratings of 15/29/21, an Evasive Maneuvers score of 5 and an Initiative rating of +11. All forms of heavy ordnance have 300 SHP and 100 AHP. Heavy ordnance follows all other rules for vehicle-scale combat and is subject to the other modifiers to their stats as noted in this sub-Chapter.
Certain combat situations may call for simultaneous combat, which is considered a special type of cross-combat. Simultaneous combat occurs when two or more distinct combat actions must take place at the same time. Examples include boarding actions (a character-scale combat situation taking place at the same time as a vehicle-scale combat situation at sea), mixed-scale combat situations wherein not all of the involved combatants are against one another (e.g. a group of characters finds themselves fighting a battle tank that happens to be inside a capital ship, which itself is fighting other capital ships) and combat happening at the same time in two separate locations. Simultaneous combat can get very complex very fast because factors in one combat action may affect factors - or even the outcome - of the others.
Depending on how the PCs are involved, the GM may have several options as to how to handle a simultaneous combat situation. If the PCs aren't involved at all, the GM can just use Simple Combat (see Chapter 9.1 for details) to determine the outcome of the action; use of goals is strongly encouraged in this case. If at least one PC is involved in combat, the GM may choose whether they want to run their combat action as a side adventure, if they want to treat the combat situations distinctly or if they just want to use Simple Combat.
Character-scale combatants can take crew or officer damage should it be indicated as the result of actions on a larger simultaneous combat scale; should a vehicle or capital ship take crew damage, any combatant inside that craft may take the damage (including PCs). When personnel damage is indicated in combat situations wherein members of the player group are involved, each combatant group rolls 1d10. A member from the group with the lowest throw will take the damage (continue rolling in the event of ties), using the same crew damage schema for vehicles/capital ships. Should it be destroyed, all characters will suffer the normal penalties for a craft's destruction; this includes any PCs that happen to be fighting aboard at the time.
The best way for a GM to deal with a simultaneous combat situation is to resolve actions in whichever action is most critical to the overall situation before going on to the remaining actions. In the event that all involved actions are equally critical, the GM should resolve actions on the largest combat scale involved before proceeding to the smaller scales.