Low Visibility

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This is a mod for the HBS BattleTech game that introduces a new layer of depth into the detection mechanics of the game. These changes are influenced by the double-blind rules from MaxTech, but have been heavily adapted to the video game mechanics.

Low Visibility[edit | edit source]

Are you seeing a bunch of ??? ? Are you having contacts with no models? You can't see enemy details? Well look no further! Welcome to Low Visibility!

This is a mod for the HBS BattleTech game that introduces a new layer of depth into the detection mechanics of the game. These changes are influenced by the double-blind rules from MaxTech, but have been heavily adapted to the video game mechanics.

This mod has been designed to work with RogueTech. In theory is should work without that mod, but your mileage may vary.

WARNING: THIS MOD LIKELY BREAKS SKIRMISH MULTIPLAYER. It has not been tested, but all due to the way it's been implemented my guess is that it won't work. You have been warned!

Summary[edit | edit source]

This mod is comprehensive, but a short summary of changes in the mod include:

  • Sensor blips can now be targeted and attacked, allowing long range builds to be more viable.
  • ECM bubbles provide protection for allies and reduce enemy sensors.
  • Enemy details are hidden and are only revealed to strong sensors and/or pilots with high Tactics.
  • The environment can reduce visibility due to snow, rain, night, etc. This makes sensors critical to success on those maps.
  • Stealth can hide enemy mechs (and your own!) allowing you to close range safely.

Target Detection[edit | edit source]

What you can detect is defined by your unit's visual lock or sensor lock. Visual Lock occurs when your unit can visually identify a target, while Sensor Lock occurs when your unit can identify a target using electronics. A unit can have one, both or no lock to a target, depending on various factors (described below).

Visual Locks[edit | edit source]

Visual Locks offer the least information, providing little more than the target chassis and it's location. At long ranges all you will be able to say is that a target is an Atlas, Catapult, or Missile Carrier but you won't be able to tell which variant it is, or what it's carrying. At close range (typically within 5 hexes or so) the pilot can approximate some values such as armor and weapon types, but these are best guesses and can't always be trusted.

Information from visual locks is shared between all friendly units. The player and allied units share visual locks, while neutral and enemy units only share visual locks between their 'faction'.

Sensor Locks[edit | edit source]

Sensor Locks offer more information at a further distance. Experienced pilots and advanced equipment can use their sensors to identify fine details of a target. Some examples include exact armor values, component locations and possibly even the pilot name.

Sensor locks only share the location and outline of a target with their allies. Each unit has to rely upon their own sensors for the detailed breakdown of weapons, armor and equipment on the target. Specialized equipment can bypass this restriction and allow allied units to share detailed information as well as general location data.

Sensor Lock Checks[edit | edit source]

Sensor Locks aren't reliable; they depend on the pilot's ability to interpret results amidst a changing electronic battlefield. At the start of each round, every unit makes a sensor range and sensor detail check.

The sensor range check influences how far out the unit can detect targets. A good roll increases the range, while a poor roll reduces it. The check result acts as a multiplier to the total sensor range of the model, after any component multipliers or additions are included.

The sensor detail check influences what information you are presented on the target when you select them. If the roll is failed, you're unable to determine any specifics of the target and have to shoot blindly at them. Successes will reveal information such as their actual weapon load-out and armor status.

The results of your current check are displayed in a tool-tip in the status bar of each player mech. Check the icons in the bottom left corner, over the armor paperdoll, for a detailed breakdown.

Electronic Warfare Equipment[edit | edit source]

ECM components generate interference in a bubble around the unit, which makes the sensor check of enemy units within that bubble more difficult. Units within the range of a friendly ECM are harder to detect as well. Powerful ECM can completely shutdown a unit's sensors, forcing them to rely upon visual lock for targeting purposes.

Stealth components makes the equipped unit harder to detect. They require an ECM component to operate, but disable the ECM bubble effects.

Active Probe components improve the quality of the units' sensors, and can break through ECM and Stealth if they are powerful enough.

Narc Beacon weapons attach a powerful transmitter to targets. For a short duration, they will emit a signal that friendly units can use to identify the target's location at any range. This signal is opposed by friendly ECM, and may be disabled if enough ECM is present to overcome it's signal.

TAG weapons identify the location and details of the target for all friendly units that receive the signal. This effect persists until the unit moves away from the position it was identified. Friendly ECM has no impact on this signal.

Implementation Details[edit | edit source]

This section contains describes how to customize the mod's behavior. The values below impact various mechanics used through the mod to control visibility and detection.

While not necessary, it's suggested that you are familiar with the information in the Low Visibility Design Doc. Since this is a lot more complex then normal.

Visual Detection[edit | edit source]

The range of visual detection in LowVisibility is typically much less than vanilla. Because sensor locks allow targeting and attacks, visual ranges have been reduced. Hopefully this provides a verisimilitude of an environment where both are necessary to survival.

No matter the circumstances, vision range cannot drop below a number of hexes equal to VisionRangeMinimum.

Visual Identification[edit | edit source]

In LowVisibility many opponent details are hidden to simulate the uncertainty pilots would experience on the BattleTech battlefield. Sensors are the best way to gain detailed information on your opponent (see the Sensor Info section below), but the Mk.1 eyeball can be useful as well.

If a unit has visual lock to a target and is within a short distance, they can approximate many target details. Units within Visual Range (which defaults to 5 hexes) will treat any opponent unit as if they have Surface Analysis.

Environmental Modifiers[edit | edit source]

Visual Lock is heavily influenced by the environment of the map. Each map contains one or more mood tags that influence the vision range on that map. When each map is loaded, a base vision range is calculated for every unit from these tags. Flags related to the ambient light the a base vision range, while flags related to obscurement provide a multiplier that reduces this range.

Base Vision Range Light Tags
15 hexes (450m) bright mood_timeMorning, mood_timeNoon, mood_timeAfternoon, mood_timeDay
11 hexes (330m) dim mood_timeSunrise, mood_timeSunset, mood_timeTwilight
7 hexes (210m) dark mood_timeNight
Vision Multiplier Tags
x0.7 mood_weatherRain, mood_weatherSnow
x0.5 mood_fogLight
x0.3 mood_fogHeavy

A map with dim light and rain has a vision range of 11 hexes * 30.0m * 0.7 = 231m. Any SpottingVisibilityMultiplier or SpottingVisibilityAbsolute modifiers on the unit increase this base range as normal.

Sensor Detection[edit | edit source]

At the start of every combat round, every unit (player or AI) makes two sensor checks. Each check is a random value between -14 to +14, assigned as per a normal distribution (aka a bell curve). The distribution uses mu=-2 and a sigma=4 value, resulting in a wide curve that's centered at the -2 result.

Check distribution.png

Each check is further modified by the source unit's tactics skill, as per the table below. (Skills 11-13 are for RogueTech elite units).

Skill 1 2 3 4 5 6 7 8 9 10 11 12 13
Modifier +0 +1 +1 +2 +2 +3 +3 +4 +4 +5 +6 +7 +8
w/ Lvl 5 Ability +0 +1 +1 +2 +3 +4 +4 +5 +5 +6 +7 +8 +9
w/ Lvl 8 Ability +0 +1 +1 +2 +4 +5 +5 +6 +6 +7 +8 +9 +10

Sensor Range[edit | edit source]

The first check (the range check) is used to determine the unit's sensor range this turn. Each unit has a base sensor range determined by its type, as given in the table below. This range is increased by SensorDistanceMultiplier and SensorDistanceAbsolute values normally, allowing variation in unit sensor ranges.

Type Base Sensor Range
Mech 12 hexes * 30m = 360m
Vehicle 9 hexes * 30m = 270m
Turret 15 hexes * 30m = 450m
Others 6 hexes * 30m = 180m

The range check result is divided by ten, then used as a multiplier against the unit's sensor range. A range check result of +3 yields a sensor range multiplier of (1 + 3/10) = 1.3x. A negative range check of -2 would result in a multiplier of (1.0 - 2/10) = 0.8x.

No matter the circumstances, sensors range cannot drop below a number of hexes equal to SensorRangeMinimum.

Target Signature[edit | edit source]

A unit's sensors define the range at which they can see a standard target in normal conditions. Equipment and environment can result in a target that's easier or harder to see, which is expressed through their signature rating. This rating is typically hidden, though components in the MechLab will indicate any increases or reductions in signature.

Target signatures act as a multiplier to the sensor range. If a unit has a sensor range check that resulted in sensors range 400:

  • A hard to detect target with signature 0.5 would only be detectable at 200m or closer.
  • A standard target with signature 1.0 would be detectable at 400m or closer.
  • An easy to detect target with signature 1.2 would be detectable at 480m.

Their signature can reduce your effective range without you ever knowing.

Players should note that forests provide a 0.8 signature, while water applies a 1.2.

Sensor Info[edit | edit source]

The second check (the info check) determines how much target information the unit will receive this round. This check is applicable for optimal conditions - enemy ECM and other effects can reduce this value on a target by target basis. The range of check results is given below:

Info Check Detail Level Details shown
< 0 No Info Failed sensor check, no information shown
0 Location Target location (3d arrow), but unknown name
1 Type As above, but type defined (mech/vehicle/turret)
2 Silhouette As above, with Chassis as name (Atlas, Catapult)
3 Vector As above, adding Evasion Pips
4 or 5 Surface Scan As above, adding Armor & Structure percentages, paperdoll
6 or 7 Surface Analysis As above, adding Weapon Types (as colored ???)
8 Weapon Analysis As above, with Weapon Names defined. Name is Chassis + Model (Atlas AS7-D, CPLT-C1)
9 Structure Analysis As above, plus current heat & stability, summary info (tonnage, jump jets, etc). Armor & structure includes current and max values. Name is Chassis + Variant name (Atlas ASS-HAT Foo, Catapult CPLT-C1 Bar)
10 Deep Scan As above plus component location, buffs and debuffs
11 Dental Records As above plus pilot name, info

First Turn Protection[edit | edit source]

On the very first turn of every combat, every unit (friendly, neutral, or foe) always fail their range check. This ensures players can move away from their deployment zone before the AI has a chance to attack them.

Components[edit | edit source]

The sections below define behaviors exposed through components, such as equipment and weapons.

ECM[edit | edit source]

ECM components emit a bubble around the unit. After every movement occurs, all units are checked to see if they are within the ECM bubble of another unit.

If they are within an enemy ECM bubble, they gain an ECM jamming modifier equal to the strength of the emitter. This reduces both Detection checks by the emitter strength.

If the unit is within a friendly ECM bubble it gains ECM protection. This adds the friendly emitter's strength as a negative modifier to any Detection Info checks made against the target.

If there are multiple ECM emitters covering a target, the strongest modifier will be applied. Each additional emitter will add +1 strength to the strongest emitter's modifier.

If an enemy unit within an ECM bubble is attempting to detect a friendly unit protected by the bubble, both modifiers apply. If there are two overlapping bubbles of jammer emitters, the enemy would have a total -4 -1 = -5 penalty from being jammed, and a further -4 -1 = -5 modifier due to the target having protection. Their checks would have a -10 modifier to detect the unit protected by both bubbles.

Active Probes[edit | edit source]

Some components apply a modifier to the unit's Sensors Range Check and Sensors Info Check. These generally add a bonus that increases sensors range, and improves resolution of target details.

These modifiers apply to both range and info. If you only want longer ranged sensors, use the SensorRangeMultiplier and SensorDistanceAbsolute on the component instead.

Stealth[edit | edit source]

Stealth components reduce an opponent's ability to sensor lock the protected unit. Stealth only applied to the unit directly, and has no effect when the enemy attempts to detect other friendly units. Stealth generally applies a penalty to the opponent's check, which reduces the Sensors Info Check. Stealth does not impact an opponent's Sensors Range Check.

Effects[edit | edit source]

The sections below discuss electronic warfare effects allowed by LowVisibility.

Narc Effect[edit | edit source]

Narc beacons launch a small transmitter that attaches to the target and broadcasts their location. LowVisibility provides an effect tag that mimics this effect by providing a strong bonus to sensor detect checks for targets that have been NARC'd.

Any effect that attaches the NARC Effect tag will apply X as a modifier to sensor checks against the unit under the effect. If this modifier is greater than the affected unit's ECM protection the unit will be marked as a sensor blip regardless of sensor range. Units within sensor range will apply the difference as a modifier to any sensor info checks.

TAG Effect[edit | edit source]

TAG emitters are special sensors that provide deep information on a target so long as they can be targeted with a laser-like beam. LowVisibility mimics this effect by providing a sensor info modifier that decays as the target moves. TAG effects are NOT impacted by ECM protection, which provides a way for players to fight against opponents with strong ECM.

Any effect that incorporates the TAG effect provides a sensor check equal to the duration of the effect. Any friendly unit applies this bonus to their sensor info check.

Attack Modifiers[edit | edit source]

Once a target has been detected it can be attacked normally, though attacks may suffer penalties based upon how strong of a lock they have to the target.

If an attacker only has sensor lock to the target, they suffer a Sensors Only attack penalty of +2 (SensorsOnlyPenalty).

If an attacker only has visual lock to the target, they suffer a Vision Only attack penalty based upon their distance to the target. For every 3 hexes away (VisionOnlyRangeStep) the attacker suffers a +1 attack penalty (VisionOnlyPenalty), regardless of the weapon used.

Zoom Vision[edit | edit source]

BattleTech has a long standing tradition of zoom vision being a standard feature on cockpits. To support this, equipment with extra zoom levels apply an attack bonus that decays over distance. Each point of X applies as a -1 bonus to the attack roll. For each Y hexes between the attacker and the target, the bonus is reduced by one, until no bonus is provided.

This bonus only applies ranged attacks. This bonus does not stack with other vision bonuses. An attacker with multiple visual enhancement components applies the highest bonus to an attack, plus +1 for each addition visual enhancement component that provides a bonus.

Heat Vision[edit | edit source]

Like zoom vision, detecting an opponent through thermal vision has been a stable of BattleTech games back to MW2. Components capable of "Heat Vision" mimic this effect by applying an attack bonus that increases the as the target heats up. The attacker gains a -X bonus to their attack for each Y points of heat the target currently has.

This bonus only applies ranged attacks. This bonus does not stack with other vision bonuses. An attacker with multiple visual enhancement components applies the highest bonus to an attack, plus +1 for each addition visual enhancement component that provides a bonus.