Explosions
Explosive Damage to Walls and Objects
Explosive damage to objects (anything that isn't a unit) is constant; grenades will always form the same blast pattern on the same terrain. The peak damage is done at the center and falls off by 10 points per tile radius.
It's known that a Blaster Bomb is the only thing capable of blasting through a UFO outer hull (walls and roof). It does exactly 200 damage at the epicenter and only ever knocks out one tile.
When we boost the power of the humble High Explosive with a game editor we see the following:
- 190 for HE strength is not enough to bust a hull open.
- 200 is, but only one tile wide.
- 210 opens up a hole 3 tiles wide
- 220 opens up a hole 5 tiles wide.
For every 10 points of HE strength above 200, it adds 2 to the width of the hole.
- reposted from discussion, NKF/Jasonred/Zombie, strategycore forums 2005 -JellyfishGreen 02:21, 25 Aug 2005 (PDT)
Blast Propagation
Blaster Bombs impart damage as follows:
Distance From
Ground Zero Damage Range
0 100 - 300
1 90 - 290
2 80 - 280
3 70 - 270
4 60 - 260
5 50 - 250
6 40 - 240
7 30 - 230
8 20 - 220
9 10 - 210
10 0 - 200
Taken from a post by Zombie. Behavior past 10 tiles is not entirely certain.
Notice how the Blaster Bomb is rated at 200 HE damage, and does that - but on average at ground zero. Then the range decreases by 10 per tile away from GZ.
Another way to view damage is relative to its edge (HPs=Health Point damage):
DFE HE MinHPs AveHPs MaxHPs N
1 Gren 0 1.27 5 15
AC-HE 0 2.50 8 10
HC-HE 2 7.90 22 10
SR 8 23.33 42 15
LR 10 24.80 48 15
BB 37 79.44 125 27
2 Gren 1 11.60 20 15
AC-HE 4 12.10 21 10
HC-HE 7 21.10 37 10
SR 12 33.60 57 15
LR 15 36.60 60 15
3 Gren 5 18.47 34 15
SR 17 43.40 70 15
LR 20 47.12 73 17
4 LR 30 60.50 91 2
5 LR 30 56.50 83 2
Where "DFE" equals Distance From Edge (1 is just inside edge of blast radius). The numbers are for Muton Soldiers (armor=10, max Health Points=125) not hit through their Under Armor, in Desert terrain.
Here we see that standard Grenades do very little damage at their edge, but Blaster Bombs are still doing tons and able to kill massive Mutons even there. (The edge for BBs was 13 tiles from GZ for the above.) The numbers also support the idea that BBs continue to decrease by 10; extending the Blast Propagation table to 13 gives 0-170; minus 10 for Muton armor leaves a max of 160; half of that (80) was seen, on average.
Zombie has posted a detailed discussion of the mathematics for blast propagation here.
Ground Zero Effect
Units at ground zero (center of blast) and the eight adjacent tiles (GZ+1; nine tiles in total) receive damage through their Under Armor. All others receive damage to the side facing ground zero (never Under Armor).
This is true regardless of whether using thrown items (grenades, Hi-Ex) or shot/launched explosives (AC-HE, HC-HE, Rockets, Blaster).
Susceptibility
Critters have the following susceptibility or resistance modifiers to explosive damage:
Silacoid 130% Sectopod 80% Zombie 80% Tanks 70% Cyberdisc 60%
So Silacoids are more susceptible, presumably because they are close to the ground.
Blast Diameters
Blast diameters differ according to terrain type. The table below was copied from a post by Zombie. To get radius, subtract 1 and divide by 2:
Grass,
Lawn,
Corn Dirt, Asphalt Polar
Fields,Weeds, Roads, White Snow,
Wheat Desert White Tin Tile Concrete Mars Mtn. Alien
Cost $/HE Weapon HE Fields Sand Shngls Roofs Roofs Walkway Sand Tundra Floors
700 15.9 AC - HE 44 7 7 5 3 1 1 0 0 0
300 6.0 Grenade 50 7 9 7 5 3 3 1 0 0
500 9.6 HC - HE 52 7 7 7 5 3 3 1 0 0
500 7.1 Prox G 70 11 13 11 9 7 7 5 0 0
600 8.0 Small R 75 9 9 9 9 7 7 5 0 0
6700+2E 74.4 Alien G 90 13 13 13 13 11 11 9 3 0
900 9.0 Large R 100 13 13 13 13 13 13 11 5 1
1500 13.6 Hi Ex. 110 13 13 13 13 13 13 13 7 3
8000+3E 40.0 Blaster 200 23 23 23 25 25 23 23 23 21
Tile Armor - Initial 6?* 5? 10 20 10? 20 25-40 40 50
See next section Dead 50? 255 255 255 30? 255 30-255 20 50
*"Wheat" is complex - see Note 3 under Tile Characteristics
Where HE is the High Exposive rating for each round and: "White Shingles" is the roof on the gas station complex, "Mars Sand" is the soil on the Martian surface in Cydonia, "Alien Floors" is the floor of an alien base (alien ships were not checked), and "Concrete Walkway" is sidewalks near buildings or roads. Buy price or manufacturing cost are also shown (part cost only; does not include labor), whether Elerium-115 is needed ("+E"), and "Dollars per HE" (Cost/HE).
For the stun bomb, see here.
Zombie and NKF theorize that terrain "sops up" (or absorbs) a portion of the damage. Each tile from ground-zero absorbs part of the explosion until the damage left is less than tile "armor". So, while the OSG clearly states that damage drops off by 10 per tile radius, apparently the tiles are absorbing some of the damage, as well. Any units or items on the ground directly adjacent to the edge of the blast are not damaged. Blast diamaters are always symmetrically round, unless some of the terrain is "harder" than the rest. For example, if a bomb opens up a hole in a UFO, the blast pattern outside the UFO will be a standard half circle for "outdoors" damage, but inside the UFO, there will be a smaller pattern.
Terrain tile properties (Armor, HE Block, etc.) can be readily seen in DaiShiva's excellent MapView program. Caution: You must install the extensive MicroSoft .NET platform to use MapView; see DaiShiva's site.
Tile Characteristics
This section is mainly for folks doing research on explosion propagation. Values were gathered with DaiShiva's excellent MapView program.
Ini Ded HEB Type _ 80 50 Most UFO floors UFOs AND ALIEN BASES 100 NDT UFO roof 100 220 100 Outer UFO walls 80 50 80 Most inner UFO walls 100 50 100 Inner UFO walls w/crown molding (See Note 1) 100 NDT Partial UFO floor tiles (near corners) 50 50 Base floors 150 50 Green Start tiles 200 50 Red elevator tiles 50 65 Purple (entertainment) floor 90 100 Dark black garden floor _ 25 255 Arctic ground ARCTIC 20 255 Road CITIES 8 255 Smooth grass 10 255 Grass patches and dirt 15 30 Gas station ceiling - 150 Flame 10 30 Gray store floor 15 30 Slate roof for buildings - 160 Flame 18 50 Gray warehouse floor - 155 Flame 15 30 Rough gray concrete store roof - 150 Flame 12 40 Pastel pink(?) indoor tile - 111 Flame 8 255 Flowers 6 50 Pink patterned carpet - Normal 20 Flame, DT 100 Flame _ 40 30 Sand CYDONIA 100 NDT Green Start tiles. All others as for alien bases. _ 5 25 Sand DESERT 5 255 Grass FARM 10 255 Dirt and cultivated fields 6 25 Wood floor - Flame 16 6 25 25 Hay loft ground floor - Normal 12 Flame, DT 25 Flame 10 255 Stable - Flame 10 30 35 Cobblestone floor - 160 Flame _ 10 30 Light green weeds add 8 armor, 25-30 Flame FOREST 8 30 Plants add armor and HEB; see Note 2 JUNGLE 40 20 Normal ground. Death tile only needs 2 TUs! MOUNTAIN 50 NDT 50 Solid mountain walls (full height) _ 15 80 Common pink(?) or gray floors, inc. Access Lift XCOM BASE 10 80 Lighter tile in center of some common floors 12 70 Blue floors 16 80 Hangar floor _ 255 NDT 0 Ramp object. See Note 4. XCOM CRAFT 255 NDT 0 Floor of craft
"Ini" is initial tile armor; "Ded" is tile armor for the next ("dead") tile that appears after the initial one is blown away. If no tile is indicated (DeathTile=0), NDT is put. (I guess this means either nothing will appear, or raw earth will appear.) Also it's not known what a Death Tile of 255 is - this is probably a flag instead of an armor value. Could mean the same as NDT. HEB is the "HE Block" value in MapView. We can only guess exactly how that works, at this point.
Note 1: The inner UFO walls with "crown molding" are the second type of inner wall. The whole third level of battleship is this, and it's also found around the control room in large UFOs.
Most solid floors etc. had no flame ("Flammable") value. Most plants and human buildings did. Some tiles look weird, but make sense when you think about it. For example, cobblestone in farms has a high flame value - but it's found as the first floor of wooden buildings. Also (Note 2:) Most largish plants (shrubs and larger) had HE Block values. The jungle, in particular, has many full trees with HE Block of 20. Don't ask me why the hay loft ground floor has HEB=25.
Note 3 (from Blast Diameters): For what it's worth, the effects of e.g. wheat and flowers in the farm map are actually added to the base tile (and add TUs to it). They are not a separate tile; they are objects. The additional TU costs can be seen in MapView, such as 2 (i.e., +2) for wheat. They also have their own armor ratings. Thus the wheat itself has Initial Armor 6, DT Armor 50 (this one shows burnt crops), which then goes to another DT (dirt) of Armor 255. But the tile it's on has Initial Armor 10, then goes directly to the same final DT as wheat (Armor 255). What this means, I don't know. Zombie, you listed wheat and corn fields in your Diameter table, but everything on the farm looks like wheat to me, and they all point to the same wheat object... ? Also, there are different types of dirt and grass. I assume you meant the common grass on the farm for your tests. I am taking a guess at what your terrain was for some of the columns... some of the descriptions are pretty succinct... probably the best thing is for you to use MapView to get them yourself. Please edit the Blast or Tile tables all you want.
It's very weird how mountain terrain death tile only has TUs of 2. Was I reading it right?? Can't wait to check it out. It looks to me like they messed up. I believe they meant to point to death tile 77, but accidentally pointed to object 76. Perhaps this explains the weirdness NKF mentioned about mountain terrain "weakening" indestructible walls? Especially if there was damage (moving it from Initial tile to the incorrect death object).
Note 4: All ramp-section objects add 4 TUs to underlying terrain except the middle and top of Avenger's ramp only adds 2 TUs. I think Danial has pointed this out before.
I tried my best with these values, but they can be awful hard to tell apart. I even broke out the magnifying glass under /Accessories /Accessibility! (Then, after I was done, I noticed that TopView clarifies just which tile is where, sigh.) Plus that was a lot of numbers to track. I did not methodically get all walls, and there are many (esp. small) objects that can be added to terrain and cause increases(?) in armor and possibly other values. Example: Rocks in the desert are separate objects, with 20 armor. So take these values as a rough guide. If you want to do research on a particular tile, please double-check MapView before spending a lot of time on it! - MTR
Experience Points
Any alien (not under mind control) caught in a blast radius will give experience points toward Firing Accuracy. So one blast can give many Firing experience points. It does not matter if the alien was not harmed (i.e., damage was blocked by armor); you still get experience points if they were in the blast radius. Mind controlled aliens are considered friendly and do not give experience points.
The Small Launcher's stun bomb also gives Firing experience. Again, even if aliens did not actually fall unconscious (or receive any stun at all). Stun bomb radius in desert terrain is 5, diameter 11.
If thrown, one Throwing Accuracy experience point will be given. Note that if no one throws it (it's dropped instead), your first soldier gets the experience (even if a tank or if dead!). Thrown objects are attributed to the last person to throw them, or default to your first soldier "slot". Your tanks always occupy the first slot(s) (but enemy tanks such as the cyberdisc do not occupy your first slot).
If you make a reaction shot with a projectile explosive, you will receive one Reactions experience point, even if many aliens were hit by the blast (giving you many Firing XPs). Technically, you were only reacting to the movement of one of the aliens.
To see how experience points translate into skill points (when combat ends), see here.
NOTE: The Proximity Grenade does NOT give Firing experience to the thrower. Instead, it gives Firing experience to the person that triggers it to explode. Keep this in mind because this tends to make it a poor choice, especially early in the game (SIGH!).
Blaster Bomb Pattern
See Also
- Damage Formula
- Firing Accuracy
- Throwing Accuracy (including throwing distance)
- Reactions
- Weapons
- Health
- Fatal Wounds
- Armor