TERRAIN

This folder contains the information used for tiles in the battlescape view, both statistical and graphical.

Each of the three files used for each tileset contains a variable amount of records. PCK files and their respective TAB files should always contain an equal amount of records.

MCD

General Information

• MCD stands for Map Control Data.
• MCD files have a variable amount of records, each of 62 bytes.
• Each record defines one of four possible terrain items (see [54]):
  • ground tile,
  • north wall,
  • west wall, or
  • object
• For example, DESERT.MCD defines a number of desert terrain items such as sand (ground tiles), sand dunes, rocks, and cacti.
• The PCK and TAB files work hand-in-hand with MCD records to define what each terrain item looks like.
• These MCD terrain items are subsequently combined to make "3D" maplets in the MAPS\DESERTnn.MAP 10x10 or 20x20 tilesets.
• The MAP tilesets are then selected from, to make a "random" desert map when a new battlescape is created.
• Sometimes more than one collection is used for a given map type; farms are made from the CULTIVAT (fields) and BARN (farmhouse) sets.
• More complex terrain types, especially UFOs and bases, tend to have many more MCD records (terrain items) and/or more than one MCD set. The maximum total cannot excede 256 records.
• Most MCD files are accompanied by respective PCK & TAB files, and vice versa.

Structure

0-7 / 00-07: Animation of the tile.

The eight bytes refer to images on the PCK files which are used in a sequence (from the first byte to the last) to animate tiles. This animation is used by several tiles on both games, such as doors (see [46]), bubbles on TFTD, blinking lifts, etc. If all eight frames are the same, it's a static tile.

8-19 / 08-13: Line Of Fire Template (LOFT) for the tile. 12 values, each references into LOFTEMPS.DAT file.

Each LOFT record is a 16x16 grid; these are stacked one over the other, with mcd[8] being the bottom. Used to create a 3D map (16x16x12) of the tile, for LOS. For more info, see LOFTEMPS.DAT.

20-21 / 14-15: Reference into SCANG.DAT file. Two-byte integer ([20] + [21] * 256 + 35 = offset). 4x4 bmp images for the top-down map; see SCANG.DAT.

22-29 / 16-1D: Unknown.

30 / 1E: Boolean: Is sliding door? See [46]

31 / 1F: Boolean: Can't be seen through?

32 / 20: Boolean: Can't be stood on? For ground tiles: non-flying units fall through. Only two ground tiles have this set: BLANKS MCD id 0 and UFO1 MCD id 0

33 / 21: Boolean: Is Wall? Used for Objects intended to act as Walls; used to make UFO, Skyranger, and Avenger outer "walls" that aren't otherwise possible as "real" North or West walls. Used for a few other things, too. Called "BigWall" in MapView.

34 / 22: Boolean: Is Grav lift? Up/Down of Lifts is determined by whether there is another one above or below in the .MAP.

35 / 23: Boolean: Is hinged door? See [46]

36 / 24: Boolean: Blocks fire?

37 / 25: Boolean: Blocks smoke?

38 / 26: Unknown - Always 3.

39 / 27: Time units used to walk across the tile. (255 means unpassable)

40 / 28: Time units used to slide across the tile. (255 means unpassable)

41 / 29: Time units used to fly across the tile. (255 means unpassable)

For [39] to [41], values range from 0 to 8, or are 255. There are only a few places where they are not all the same ([39]=[40]=[41]):

Walk Slide Fly File    Description

  2   0    2   Avenger Middle ramp object

 255 255   4   Arctic  Water pools in ice (18 ground MCDs) 

  2   2    0   U_Base  Death objects for large round containers in alien bases (four quadrants)...
                       thus, their remnants don't add TUs for fliers

  1   1    0   U_Base  Little green plant objects found on black "base garden" flooring

  2   2    0   Urbits  Two death objects (splinters on ground) for city's tall green picket fence 
                       (one is a North-wall fence, the other is a West-wall fence)

Which of the three movement types a given unit uses is determined by UnitRef[11]. Note that by default, ALL units are "walkers".

42 / 2A: Armor of tile.

• Tile must take this amount of damage to be destroyed, at which point it changes to mcd[44].
• Terrain items do not "remember" damage (like units); terrain is either destroyed (if damage >= armor) or not.
• Some things are set to 255 to mean "indestructible" but actually, anything >100 is indestructible in a non-hacked game, and anything >127 (for explosives, 255/2) or >191 (firearms, 255x.75) cannot be destroyed, even in a hacked game (see Damage re: Damage to terrain).
• With explosions, all four terrain items in the tile are hit by the same strength, but firearm shots target only one of them.
• For a loopy exception to explosions being equally applied (due to erroneous data), see Mountain Madness.
• NKF: I suppose you could make a gate out of this by creating two tiles, each easily destroyed, which change to the other when hit. One could be walked across, the other could not.

43 / 2B: HE Blockage

44 / 2C: Tile becomes a tile of this type (i.e., this other MCD record in the same MCD file) when destroyed. Also known as the death tile. Also see [53].

Note: If [44]=0, it means there is no death tile per se; it reverts to a "raw earth" (BLANKS[01]) tile if on ground, or nothing if in air. (It does not revert to the MCD id 0 record in the current collection.)

45 / 2D: The higher this is, the less likely the tile will be set on fire.

46 / 2E: If the tile is a door ([30] or [35]), the tile will become this tile number when opened. Animation [0] (see [0] to [7]) is shown until someone walks through the door, in which case it cycles through its animation stopping and holding Animation [7]. Then it will return to a closed door next turn.

47 / 2F: Unknown - Always 0. MCDEdit calls this "Keycode".

48 / 30: Signed value; add this to the graphical Y offset of units or objects on this tile. A.k.a. terrain level.

49 / 31: Subtract this value from the graphical Y offset of the tile image (used for hills).

50 / 32: Unknown - Always 0.

51 / 33: From 0 to 10, amount of light blocked by tile.

 0 Blocks no light.
... up to ...
10 Blocks all light.

52 / 34: Footstep sound effect. Most likely an index to the .CAT file RAW wave -BladeFireLight

0 Not used in XCOM (makes a metal sound if hacked); is used on TFTD for some objects -Hobbes
1 Metal
2 Normal (Grass, Wood, Dirt)
3 Three mountain ground tiles, and some city apt. furniture objects that can't be walked on?
  (six furniture objects might've been - but they're death tiles that nothing points to)
  Uses same sound as 6.
4 Pool of water (Not used in XCOM)
5 Sand (Desert)
6 Martian
7 Snow (Not used in XCOM, Arctic actually uses 2)

53 / 35: Tile type:

0 Floor
1 West Wall
2 North Wall
3 Object

In the map, there are four bytes per tile: One each for the floor, west wall, north wall and object. If one of those changes (eg Is destroyed, or in the case of a door, opened), it is removed from the map and a new object is placed instead. This byte is used to work out which of the four map bytes should recieve the new object.

For example, in the mountains, if you destroy the ground tile you get an object (tree stump). The new tile gets written into the fourth byte of the map record, even though the original tile that was destroyed belonged in the first byte.

As for the potential for change in tile type when becoming death tile ([44]): There are 22 instances of Mountain Madness (ground to object), 1 instance of North Wall becoming an object (XCOM1 northwall door becomes rubble), one MCD record with tile type of 10 (Barn 7 which looks like a North Wall and becomes northwall when killed; obviously a typo'd Tile Type), and 31 total instances on 18 different tilesets where objects become ground upon dying (probably to "scorched earth", but this was not checked).

54 / 36: Explosive type; [55] must be >0:

0 HE
1 Smoke

Notes:

1. To see explosive objects in XCOM, see Explosions#Explosive Map Objects.
2. Type 0 (HE) explosions follow the usual rules for explosions (average damage to units decreases by 10 per tile outward, etc.).
3. Hackers: Type 0 (HE) terrain items with little or no armor ([42]=0) are obliterated before exploding (i.e., they won't explode, no matter how high [55] is). Probably also depends on, if it was a very big blast relative to the armor.
4. Chain reactions are exceedingly difficult to set up (per Hobbes). Most of the time when you see e.g. the four sections of the Navigator's table explode, it's because you used explosives that actually set off each one individually. It has to do with a balance of, among other things, not obliterating the object (see previous point).
5. Type 1 (Smoke) explosives are strange, and mainly only affect aliens - and very haphazardly at that. XCOM units are only very rarely affected; I could only get it to work if they were 1) unarmored, 2) on a diagonal, and 3) no other objects are "in the way" between the blast moving "over and up" or "up and over" to the diagonal (blast propagation never moves directly diagonally per se; see Explosions#Playing With Fire). -MTR
6. Chain reactions are not possible with Type 1 (Smoke) explosive objects.
7. Also, when dealing with smoke damage, remember that if there is already tons of smoke on the map (filling up the smoke table) such that no new smoke can appear, you might get unexpected results (or no effect). Hobbes: One strange thing that can happen when there's already too much smoke on the map and an object with [54]=1 explodes is that the alien dies and in the dying animation there's smoke on that square. Just in the dying animation, not after he's down? -MTR - I can't remember right now if the smoke remains afterward. Next time it happens I will check it Hobbes 12:00, 18 Nov 2005 (PST)
8. There are no "naturally occuring" HE explosives tiles in UFO. All explosive objects are MCD[54]=1.
9. TFTD uses both values for [54], 0 (more common, like the barrels on Port) and 1 (the Synomium device on Grunge/Artifact Site).

55 / 37: Strength of explosion when tile is destroyed.

56 / 38: Smoke blockage. This is set to 0 for all UFO tiles!

Perhaps [36] is used only? A varying [56] might have been where the 2 un-used smoke sprites would have come in. --Danial

57 / 39: The amount of turns this tile will burn for.

58 / 3A: Brightness of tile. Amount of light produced.

11 MCDs produce light: 7 alien base objects (several pulsing fuel pods and several 4-part round "museum containers"), 2 XCOM base ground tiles, and 2 city objects (street lamp and large standing room lamp). See Night Missions for pictures. Oddly, values range from 1 for the street lamp to 16 for the alien base museum containers, so lower values must be brighter. The distances of projected light have yet to be determined, but note that flares and personal lighting ignore vertical distance... at night, a soldier can see aliens on the ground exactly 9 tiles away, regardless of whether the soldier is at ground level or 4 levels high.

In practise, it seems if this is not zero then the tile will be fully illuminated regardless of the value. - Bomb Bloke 06:48, 20 June 2008 (PDT)

59 / 3B: Special properties of tile. Determines what is salvaged at end of mission:

 0 No Special Properties
 1 Starting Point (place to Abort mission)
 2 UFO Power Source
 3 UFO Navigation
 4 UFO Construction
 5 Alien Food
 6 Alien Reproduction
 7 Alien Entertainment
 8 Alien Surgery
 9 Examination Room
10 Alien Alloys
11 Alien Habitat
12 Dead Tile
13 End Point (from surface of Mars to base)
14 Alien Brain  (final mission victory condition)

60 / 3C: Set to 1 for most (but not all) non-death-tile XCOM base objects (TileType=3). All other MCD records set to 0. MCDEdit calls this "Victory Points" - so presumably you lose VPs based on how much of your base is destroyed?

61 / 3D: Almost half (560 of 1317) MCD records have widely varying values here, from 1 to 255 with no apparent pattern or preferred value. The remaining MCD records are 0. Some kind of pointer?

List of MCD Files

Here are the 27 MCD files in XCOM. Here's a list of the number of MCD records in each (1,317 total):

File            Terrain              Records
avenger         Avenger                 59
barn            Farm                    29
blanks          All                      2
brain           Alien Base               4	
cultitav        Farm                    37
desert          Desert                  66
forest          Forest                  83
frniture        City                    26
jungle          Jungle                  82
lightnin        Lightning               42
mars            Cydonia                 36
mount           Mountain                78
plane           Skyranger               65
polar           Polar                   81
roads           City                    23
ufo1            Small Scout             20	
urban           City                   112
urbits          City                    25
u_base          Alien Base              67
u_bits          UFOs                     8
u_disec2        UFOs                    17
u_ext02         UFOs                    34	
u_oper2         UFOs                    15	
u_pods          UFO/Alien Base          11	
u_wall02        UFO/Alien Base/Cydonia  47
xbase1          X-COM Base              97
xbase2          X-COM Base              62

And here's the same list for TFTD:

File            Terrain              Records
asunk		Sunken Galleon		50
atlantis	Atlantis		77
barracud	Barracuda		46
blanks          All                      2
cargo1		Cargo Ship	       103		
cargo2		Cargo Ship		13
cargo3		Cargo Ship		 6
coral		Coral			28		
crypt1		Crypt			45		
crypt2		Crypt			49
crypt3		Crypt			12		
crypt4		Crypt			 7
debris		Seabed			50
deckc		Liner Ship (Top)	18				
entry		Entry			12		
grunge1    	Artifact Site		38		
grunge2      	Artifact Site		 8
grunge3     	Artifact Site		10
grunge4      	Artifact Site		37
hammer		Hammerhead		44		
island1       	Island			50
island2       	Island			50
island3       	Island			35
leviath       	Leviathan		47
linera		Liner Ship		99
linerb		Liner Ship		24
linerc		Liner Ship		40
linerd		Liner Ship		23
manta		Manta			44	
msunk1		Sunken Ship		50
msunk2		Sunken Ship		29
mu		Mu			80
organic1	Alien Base/Level/Entry	96
organic2	Alien Base/Level	10
organic3	Alien Base/Level	 4
pipes		Pipes			55
planes		Sunken Plane		79
port01		Port			95	
port02		Port			78
psynom		Alien Base/Level	 2
pyramid       	Artifact		24
rocks	       	Artifact/Seabed/Galleon	15
sand	      	several			20
sea          	several			18	
triton		Triton			46
uext1		?			 4
uext2		USO/Entry		 9
uext3		USO/Entry		25
ufobits       	several			 5
uint1		USO			41
uint2		USO			11
uint3		USO			14
volc		Volcanic		80
weeds		Artifact/Coral/Seabed	10
xbases1      	X-COM Base		87
xbases2     	X-COM Base		42
xbases3       	X-COM Base		37
xbases4       	X-COM Base		43
xbases5       	X-COM Base		42
xbits		Cargo Ship		39

Additional Information

MikeTheRed's MCD Database

An Acccess 2000 copy of all MCD data is here. It's from X-COM DOS 1.4, but AFAIK, all X-COM versions use the same data (even down to the buggy Mile-High Madness MCD record). You will need to use this wiki page to understand it; I did not name the fields. They're just called by their offset address (see above). This Access database can be readily exported to Excel if you want. Or contact me. There are also a few files giving overall stats; the "Exclude" field for tblFileTypes only means, I excluded them for most counts I've made. There are also a few queries that might or might not be helpful.

BladeFireLight's MCD Info

Another in-depth look at MCD (and more) can be found on this message by BladeFireLight. His post also contains a HexWorkshop template for viewing MCD files in a logical manner.

MCD Editor

Koralt's MCDEdit can view or modify MCD files. Find it here: mcdedit.zip. To see a screencap, scroll to the very bottom of BladeFireLight's MCD posting (above). MCDEdit needs vbrun200 to run!

MapView

DaiShiva has an excellent utility called MapView for viewing or editing maps. However, it does not allow editing of MCD terrain items per se, AFAIK; just moving/placement of them. Caution: You must install the extensive Microsoft .NET platform to use MapView; see DaiShiva's site.

BombBloke's Hacked Desert Terrain

Bomb Bloke has a numerical (ground) tileset which makes weapon damage blast testing easy as pie. It also has a little applet that lets you edit MCD variables Armor [42], HE Block [43], and Explosion Strength [55] (but not type, [54]), and it includes all four types of terrain item. Find his hacked terrain here or bundled with a savegame here. To see a screencap of the tiles in action, see this message.