Flashpoint Campaigns Southern Storm - Dev Log #4
If You Can See It, You Can Kill It
Today we will dive deeper into the game's spotting, shooting, and ammo mechanics to get a better feel for how those actions work and what to expect when playing the game.
Spotting per Sensor per Platform
We do a 3D line-of-sight check for each unit and each sensor in that unit. We distinguish between a line-of-sight passing through objects in the hex and a line-of-sight passing over objects in the hex.
For line-of-sight calculations, the terrain is treated as many plateaus, each containing objects on their terrain and atmosphere above them. The objects and the atmosphere above it have different properties concerning blocking/attenuating the (optical, thermal, RADAR) line of sight. See the image below.
Various Lines-of-sight, taking into account the atmosphere (hatched) above hexes and the objects in the hex.
Spotting enemy units are impacted by the time of day. Dawn and Dusk impact the effectiveness of thermal sights as the ambient temperature passes the surface temperature of objects in the environment. Night presents a challenge as the moon's low illumination directly affects the various sensors' visibility ranges.
As seen in the image above, each unit selected for Line of Sight (LOS) shows highlighted hexes visible from their current location, range rings for Enemy Detection, Classification, and Identification for the best active sensor on the platform. As noted above, how far you can see is based on the visibility, time of day/Illumination, sensor, and the actual terrain and hindering objects.
Speaking of the weather and Illumination, you can find that information in the weather panel. The panels have a different look depending on the time of day and the weather. These changes can be seen in the images below. As the sun rises and sets during the game, the level of illumination will change, these panels change colors, and the map has an overall color to match.
We have some LOS tools so you can see both individual units (below is an M1A1 on a hill will very good LOS) and an overlay for All Units of your force.
Above is the All LOS view, and the currently selected unit LOS is highlighted on the overlay. You can also SHIFT-Click on an empty hex to see the LOS from that location.
One other type of spotting beyond optical and thermal is radar. We have air and ground search radars modeled in the game (ground search is new to the game system). The wavy orange lines and the small orange dot on the counter indicate an active radar emitter. The highlighted hexes show the radar LOS from the emitter. The emitter can be set on or off. Where ground radars (GSRs) help paint a picture of where an enemy may be, the units themselves do not have weapons to engage spotted units. Other forces will need to be maneuvered to spot and engage enemies.
Using sensors and eyeballs to scan for targets is only one part of the spotting equation. The other end of it is how spottable the enemy units are. The range at which a unit may be visible to an enemy is based on several factors, such as unit size, unit movement, shooting or not, weather, and terrain effects. All of these can change from location to location. The ranges also depend on the type of spot, such as visually, thermally, or by radar. Other factors that can impact are the type of unit (recon can hide better) and special abilities like stealth or camouflage.
A Review of the Red Storm Combat Model
We’ve done a major uplift on the direct fire model going from Red Storm (RS) to Southern Storm (SS) and beyond. Let’s outline the Red Storm view of things and also list some areas of dissatisfaction.
Direct fire in Red Storm is highly aggregated and simplified.
Subunits are grouped by type (infantry squad shoots separately from a machinegun team, T-80 with ATGM ammo shoots separately from T-80 without missile rounds).
The grouping is done for shooters and targets, so all the shooters of a specific type only engage one target subunit type in a combat event.
We calculate the chance of a kill, then multiply by the number of shooters. This can be more than a 100% chance, so we roll a die only for the remainder. (example: 4 shooters, chance to kill is 40%. Aggregated, that is 240%, which is 2 kills and a 40% chance at a third.
There was no model for control and distribution of fire.
That means there is no attempt at limiting overkill (everyone in a platoon may well end up shooting at the same single enemy subunit).
It’s assumed every subunit in the target unit is visible to every subunit in the attacking unit.
Ammunition on a platform is aggregated into a total “shot count”. For fighting vehicles (tanks and infantry fighting vehicles), this is a combination of machinegun ammo, main gun ammo, and ATGMs. For Attack helicopters, it’s often a combination of machine gun/autocannon, ATGMs, and rockets. Ammo state is an aggregate percentage of remaining shots, with no tracking by type of ammo.
We observed that all the above result in a few things that are a bit unrealistic:
Basic loads of ammunition (what a unit can carry on their vehicles for a battle) lasts, typically, only a third to half a battle.
Units frequently incur incapacitating losses in a single engagement (in way too many cases, entire companies are annihilated in a single volley).
It wasn’t possible to implement some finer, low level tactical doctrine that has an impact on the fight. These are things like medium strength ATGMs (like the M47 Dragon) were to be used against MBTs (Main Battle Tanks) using flank/rear shots only and light anti-tank weapons were to be fired in volleys of three or four against MBTs, even from the flank/rear.
While metal armor has a close fit to a few “rules of thumb” (for example, frontal/flank/rear/top thickness ratios), those don’t hold up when considering “armor enhancers” like composite armor and reactive armor. Another inconsistency is turret vs hull, both in size (and so, what can be hit) and armor thickness.
ADL (Air Defense Limited) systems weren’t really limited enough, both in range and engagement geometry. In RS, ADL basically meant “can shoot at helos”.
Low ammo state is a real problem. We absolutely didn’t want to see units killing more tanks that the amount of tank killing ammo they could carry. That was very tricky to do well without building all the stuff to track ammo by type. The trade-off we made was to have units not engage based on a low percentage of remaining ammo, which means some units wouldn’t fire when the really should.
Enter the Southern Storm Model
The key changes that really address the worst of the above deficiency list are listed below. We’ll address each of these in detail later in this Log.
Do all shoots on a Subunit vs Subunit basis.
Do a spotting check at the Subunit level. A unit being spotted doesn’t mean every shooting unit has a target at the moment of the shoot. And it doesn’t mean that are no Subunits in the target Unit that aren’t engageable by any Subunit in the shooting unit. At that moment in time, some shooters have no targets and some targets are hidden from all shooters.
Track all ammo in a round by round, Subunit by Subunit basis.
The secondary list of improvements is:
Add geometry constraints to ADL systems shooting at helicopters. Now, these are range, helo motion, and engagement aspect.
Range: this is largely due ADL systems having a primary role of attacking ground targets. Additionally, helos tend to move at much higher speeds that ground targets and even when hovering, can radically reposition is a time much shorter than ADLs time to conduct and engagement. To this end, ADL systems are limited and can’t shoot their maximum weapon range against helos. The rule of thumb here is under 1500 meters (less for machineguns).
Helo motion and Aspect: Due to their speed, helos are extremely difficult to engage in crossing or opening (flying away from the shooter) shots. We limit ADL engagements to either hovering helos or the 60 degree frontal arc for moving helos.
Medium ATGMs and Target Aspect: By the late 1980s, both the US and Soviets had a number of ATGMs that were earmarked for replacement, but still in service. These were unlikely to be effective against the frontal armor of MBTs. We do a check of warhead versus situational protection of the target and disallow some frontal engagements. Flank or rear engagements against ground targets happen either by a surprise shot (target unit has not yet spotted the firing unit) or by same-hex combat in locations with high concealment and cover. So systems like the M57 Dragon might not engage even when a tank target is in range. They are plenty strong to engage lightly armored targets from all aspects within the full range band.
Improved Armor Protection Model: Armor enhancements (skirts, reactive armor, composite armor, etc) now have separate turret and hull ratings by aspect (front, flank, top, rear). Turret size and base armor are now factored into the vehicle protection rating.
Overkill Model: In a perfect world, one does not have two people/systems engage the same target unless directly ordered to do so. Alas, the world is imperfect and combat is rushed, chaotic, and extremely difficult to coordinate, let alone synchronize and optimize. We added a fire control and distribution model that has an overkill cap of 2, meaning that up to two shooters may end up engaging the same target Subunit.
Subunit Level Combat Resolution
In the Red Storm model, if the attacker had a good enough Pk (probability of kill) by type and enough shooting platforms of that type, there would be some “automatic kills” and then a small variance. So, that gets you on the far right side of the Bell Curve on that. There was no such thing as “most missed” or “all missed”. Ammo expenditure was uniform, too.
The following changes were made to the system:
Shoots are set up so a shooting platform targets a specific Subunit in the target unit.
We “roll the dice” on each shoot. Hit or miss, kill or survived is one-for-one. No automatic kills, and it’s quite possible for all to miss. A large number of low percentage shoots won’t necessarily equate to a kill in every engagement.
Fire Control and Distribution
A direct fire engagement is but a fraction of a minute long. Shooters and targets are “somewhere in a 500 meter hex”. It’s unrealistic to the point of affecting outcomes to assume everyone can see each other. So we do a modified spotting check to determine which of the Subunits in the target unit a shooting Subunit can see. That is the beginning of the shooters target list. And that feeds into the basics of a Unit’s control and distribution of fire in an engagement.
This is a multi-step process and the key points are:
Determine which Subunits in the target unit each shooting subunit can see.
Filter out target Subunits that aren’t engageable due to range constraints, weapon/ammo capabilities (rifle vs tank or out of main gun rounds, for example). These are vulnerable targets that are visible to the shooter.
Identify which visible targets are threatening (can kill the shooter), as humans tend to prioritize these.
Cross vulnerable, visible, and threatening targets. These are the top priority for a given shooter subunit.
At the Unit level, start assigning (randomly) shooters to targets, keeping in mind, no more than 2 shooters per target and first priority for a shooter is visible, vulnerable, and threating and second priority is visible and vulnerable.
In many cases of a platoon sized Unit engaging a Company sized unit, it may look textbook. As the size ratio gets closer to 1:1, expect to see more overkill (two shooters on one target). When there are more shooters than targets, the overkill cap means some shooters that see the targets will hold their fire.
Tracking Ammo by Round and Setting Loadouts
Discreet Ammo Tracking was a lot of work to build into the new game engine for Southern Storm. In Red Storm, we said, “this platform has this weapon, and the weapon has that many shots, and the ammo types it has are these.” Ammo was tracked at the Unit level as just the total number of shots. So a Bradley IFV might have 90 shots of 25mm autocannon, 120 shots of 7.62mm coax machine gun, and 7 TOW missiles for a total of 217 generic shots. Each engagement consumed a shot. When the number of remaining shots dropped low enough, we disallowed TOW shots. There was no differentiation between the 25mm HE and AP rounds. Same with tanks and artillery systems. We had to do better this time to have a more detailed simulation.
In Southern Storm, each weapon has a basic loadout. Where there are multiple ammo types for gun/tube and rocket pod weapon systems, we specify how many of each. We do place constraints on ammo/target-type matchups. For example, we use HEAT from a tank main gun against lightly armored targets as long as the HEAT ammo lasts. That’s what trained human crews do, after all.
Overall Combat Improvements:
A few more Developer Blogs detailing more features will be coming in the following weeks as we ramp up to release. Please feel free to comment and ask questions on the Southern Storm Forum on the Matrix Games site. We will circle back to Blog #4 on the AI next time.
Until then, have a great week!