Things represent players, monsters, pick-ups, and projectiles. Inside the game, these are known as "actors." They also represent obstacles, certain decorations, player start positions and teleport landing sites. See thing types for a listing of all things.
DoomEd numbers are the numbers used in the editor to represent an actor. When the map is loaded, an actor that corresponds to that number will be spawned at the location of that map thing. Although many actors have DoomEd numbers, not all of them do. For instance, a blue key card has a DoomEd number, but a rocket flying through the air does not.
Hexen extended upon the things lump. Hexen things may contain an action special which is executed upon death or pickup of the thing (for monsters and items, respectively). Hexen format also introduced true z-clipping, allowing placement of monsters on the z-axis. Finally, Hexen monsters are also able to have a tag similar to sectors. This is called the thing ID or TID.
Offset
Size (bytes)
Description
0
2
Thing id (tid)
2
2
X position
4
2
Y position
6
2
Starting height
8
2
Angle facing
10
2
DoomEd thing type
12
2
Flags
14
1
Hexen action special
15
1
Argument 1
16
1
Argument 2
17
1
Argument 3
18
1
Argument 4
19
1
Argument 5
Note that Hexen things are 20 bytes in size; 10 bytes larger than things in Doom.
Hexen Flags[]
bit
hex
description
0
0x0001
Thing is on skill levels 1 & 2
1
0x0002
Thing is on skill level 3
2
0x0004
Thing is on skill levels 4 & 5
3
0x0008
Thing is deaf
4
0x0010
Thing is dormant - it will not wake up until it is activated using Thing_Activate
5
0x0020
Thing appears only to the Fighter class
6
0x0040
Thing appears only to the Cleric class
7
0x0080
Thing appears only to the Mage class
8
0x0100
Thing appears only in single-player games
9
0x0200
Thing appears only in cooperative games
10
0x0400
Thing appears only in deathmatch games
Strife Format[]
Strife did not alter the thing structure like Hexen did, however it did make use of the unused flag bits.
Strife Flags[]
bit
hex
description
0
0x0001
Thing is on skill levels 1 & 2
1
0x0002
Thing is on skill level 3
2
0x0004
Thing is on skill levels 4 & 5
3
0x0008
Thing stands still (only useful for specific enemies)