Difference between revisions of "Destroying Terrain"

Revision as of 08:52, 28 November 2013

Most terrain features found on the battlescape can, with sufficient firepower, be destroyed. UFO outer hulls can be breached with a Blaster Bomb, inner UFO hulls can sometimes be breached by a Heavy Plasma, and weaker structures can be destroyed by more conventional weaponry, such as Grenades or sometimes even Rifles.

Being able to clear terrain in this manner is of great value. Aliens can lurk behind a wide variety of structures, ready to ambush you the second you enter their sight. Destroying terrain flushes the aliens out into the open, where they can be engaged far more safely. Entering rooms via breached walls is also usually far safer than coming in through an existing door — a common ambush point.

Damage vs. terrain

The general rule is that explosions will do a fixed 50% of their rated damage to a terrain feature, and projectile/beam weapons will do between 25% and 75% of their rated damage. The 50% damage for explosions is at the center of the explosion; damage will decrease by a constant amount the further away from the center you go. For more information on explosions in general, see Explosions.

If the damage dealt exceeds the terrain's damage rating (or "armor"), the terrain will be damaged or even destroyed. If the damage is equal or less than the terrain's damage rating, the terrain will be completely unharmed. See Explosions#Tile Characteristics for a table detailing several terrain types and their damage ratings.

UFO walls

The outer hull of a UFO has a damage rating of 100 points: as a result of this, only Blaster Bombs (Damage = 200) can breach them. Inner hulls and doors have a damage rating of 80 points. Heavy Plasmas, with a base damage of 115, can do between 28.75 and 86.25 points of damage to terrain. 6.25 values out of a range of 57.5 possible values (6.25 / 57.5) is 0.1087, which would mean Heavy Plasma shots will breach inner UFO walls 10.87% of the time. (Initial testing suggests this figure is correct, or nearly so: 250 Heavy Plasma shots breached 32 inner walls, for an average of 12.8%.) Expressed a different way, it should take an average of 9.2 Heavy Plasma shots to breach a UFO wall; three shots (one auto shot) have only a 29% chance of creating a breach, and even a full clip (35 shots) has a 1.78% chance of failing to break through.

Tank/Laser Cannon and Hovertank/Plasma both have a base damage of 110, which translates to a range of 27.5 to 82.5 against terrain objects. (2.5 / 55) is 0.0455, so these tanks should be able to breach inner UFO walls 4.55% of the time. It should take an average of 22 shots to breach a wall with either of these weapons.

The Hovertank/Launcher's fusion ball munition has an explosive damage of 140. 50% of 140 is 70, which means a Launcher tank can never breach inner UFO walls, although they can breach "vulnerable walls."

Security walls

Certain inner UFO walls and doors are more durable than the average inner wall. These so-called "security walls" have a damage rating of 100, like UFO outer walls, and can only be breached with the use of a Blaster Bomb. Security walls have a smooth, unsegmented appearance, with several bands running along the top. Security doors are darker than normal UFO doors and do not have a line running down their centers. The upper level of Battleships are constructed solely with security walls, although security doors are only used to enclose the central lift. See image below.

Vulnerable walls

A few wall types in UFOs are far easier to breach than normal inner walls. Most UFO navigation rooms (i.e., the bridge) have a few walls sporting a green and black computer display (see image above). These walls have a damage rating of 70 (versus 80 for normal inner walls) and can be more easily breached by a Heavy Plasma. They can even be breached by a direct hit from a Launcher tank's Fusion Ball.

Weaker still (60 damage) are the orange or blue flashing Alien Entertainment walls found in certain areas. The outer northern and western walls of alien base command centers are constructed of these walls (see image below), and are easy to breach — making for a safer entry point than the doors on the western face. Furthermore, on the northern side of the inner wall, there is a single computer panel wall which is easy to breach (all the other sections are "security walls" and can only be breached by a Blaster Bomb).

UFO floors

Like walls, floor tiles can be breached. Normal metal UFO floors have a damage rating of 80, but cannot be bypassed until they are fully destroyed. This requires two shots at a minimum: one to damage the floor, and another to destroy it. A damaged UFO floor has a damage rating of only 50, so it is not terribly hard to fully breach a UFO floor.

Breaching floors is useful in much the same way as breaching walls is: it allows your soldiers an alternative and often safer entry point into a room which may contain several aliens. Floors both above and below your soldiers can be breached. To shoot the floor above you (in essence, the ceiling), you must aim at a point on the level above you. To shoot at the floor of your current level, just shoot at a square not bordered by any walls (or else the walls will be shot at instead of the floor). Naturally, soldiers in Flying Suits are needed to take fullest advantage of a hole in the ceiling.

Shooting through the ceiling may be of greatest use when storming an alien base command center. The command center's purple floors are weaker than the metal variety (50 intact/65 damaged — Heavy Plasma works well), and if you pick the right location, you can come up hidden behind an object. You may also be able to see and attack aliens on the upper floor once the ceiling is shot out, which is a much less risky approach than taking the lift up blindly into their midst.

Breaching walls and line of sight

If you shoot through a wall (or ceiling) and find yourself facing an alien, the alien will often return fire as soon as it sees you. To minimize this danger, it is best to shoot at walls from an oblique angle, keeping the shooter out of the aliens' line of sight. Return fire will only be directed at the shooter (if visible); other units standing in front of the breach will not be fired upon until they act, allowing you to get in the first shot at any aliens you discover on the other side.

Terrain structures

These figures were researched using the MCDEdit program.

Many structures found in one terrain set will be used by another terrain set, with identical properties. For instance, UFOs and Alien Bases contain a large number of common items.

UFO structures

Terrain Object	Damage Rating
Outer Wall/Door/Ceiling	100
Inner Wall/Door	80
Security Wall/Door	100
UFO Power Source	50
Elerium-115*	20
Blue Chair	60
Navigation Console (wall)	40
Navigation Table (octagonal)	15
Round Fuel Pod	20
Oblong Fuel Pod	30
Flashing Wall (Alien Entertainment)	60
Pulsing Globe	20
Green on Black Computer Panel	70
Intact Metal Floor	80
Damaged Metal Floor	50
Intact Purple Floor	50
Damaged Purple Floor	65

* Do not use explosive munitions near a UFO Power Source if you wish to collect the Elerium contained within it.

X-COM Craft structures

Terrain Object	Damage Rating
All surfaces	255

X-COM craft are meant to be indestructible (thank goodness!)... but see Explosions#Mile-High_Madness

Alien base structures

Terrain Object	Damage Rating
Dirt Wall (surface)	100
Dirt Wall (interior)	100
Metal Wall	80
Windowed Wall	100
Display Cases	10
4-space Vats	60
1-space Vats	30
Command Center Table (octagonal)	15
Alien Plants	5-40*

* Green ones are 5-14, more colorful ones 20-40 depending on size

X-COM base structures

Terrain Object	Damage Rating
Wall	80
Dirt Wall (interior)	60
Door	50
Hangar/Access Lift/General Stores Door	75
Fuel Drum	12
Missile	20

Farm structures

Terrain Object	Damage Rating
Wooden Wall	12
Door	12
Brick Wall	25
Stairway(lower)	16
Stairway(upper)	20
Wheat	6
Hay Bale	4
Flowers	8
Vegetables	10
Apple Tree	16
Normal Tree	22
Damaged Tree	15
Stone Wall	25
Hedge	12
Fence	11

Forest structures

Terrain Object	Damage Rating
Trees/Logs (various)	13-18
Large Tree (trunk)	24
Large Tree (branches)	18
Bushes	12
Hill	30

Urban structures

Terrain Object	Damage Rating
Grey Brick Wall	25
White Wood Wall	14
White/Blue Doors	12
Yellow Inner Walls	25
Beige Warehouse Wall	30
Crates	20
Stairway	25
Green Door	30
Smooth Grey Wall	30
Glass Door	15
Misc. Retail Objects	5-16
Misc. Furniture	4-22
White Picket Fence	8
Grey Metal Fence	20
Brown Wood Wall	11
Hedge	8
Fruit Tree	20
Flowers (incl. Planter)	8
Pillar	35
Fuel Pump	18
Light Post	20
Garbage Can	15
Red Post Box	14
Hydrant	30
Phone Booth	25

Polar structures

Terrain Object	Damage Rating
All Surfaces	25

Desert structures

Terrain Object	Damage Rating
Cacti	15-20
Tree	16
Damaged Tree	24
Hills (dunes)	30

Jungle structures

Terrain Object	Damage Rating
Small Trees	12-20
Small Ferns/Fronds	5-12
Large Ferns/Fronds	16-20
Large Tree (trunk)	25-26
Large Tree (fronds)	8
Large Tree (branches)	20

Mountain structures

Terrain Object	Damage Rating
Rocks	20-30
Hills	30-50
Trunks/Logs	20

Cydonia structures

Terrain Object	Damage Rating
Rocks	40-80
Small Crater	40
Large Crater	70
Pyramid	70-80
Pyramid Windows	60
Brain	40

Weapon damage ranges

Projectile/energy weapons

These are the damage ranges of these weapons vs. terrain objects (0.25 to 0.75 their normal rated damage). Their damage range vs. living creatures is between zero and twice rated damage.

Pistol	6.5 - 19.5
Rifle	7.5 - 22.5
Autocannon-AP	10.5 - 31.5
Laser Pistol	11.5 - 34.5
Plasma Pistol	13 - 39
Heavy Cannon-AP	14 - 42
Laser Rifle	15 - 45
HWP Cannon	15 - 45
Plasma Rifle	20 - 60
Heavy Laser	21.25 - 63.75
HWP Laser or Plasma	27.5 - 82.5
Heavy Plasma	28.75 - 86.25

Explosive weapons

Damage listed is for center of explosion, decreasing with distance. Damage range vs. living creatures is between one to three times these values.

Autocannon-HE	22
Grenade	25
Heavy Cannon-HE	26
Proximity Grenade	35
Small Rocket	37.5
HWP Rocket	42.5
Alien Grenade	45
Large Rocket	50
High Explosive	55
HWP Fusion Bomb	70
Blaster Bomb	100

Built-in alien weapons