There has been a fair bit of confusion on how to add the DOM gametype to a UO map, so hopefully this will help you by clarifying what you need to do.

First, we need to think about our map layout, and decide on 3 things

1) Where the Allies Base will be
2) Where the Axis Base will be
3) Where we are going to position our flags

Once we have that roughly in our minds - then we are ready to proceed

For simplicity - we are going to assume that our map looks like the following:

A
1
2
3
4
5
X

(ya...i know...a straight line map...woohoo....but it will do for this situation)

In the above we will make

A = Allies Base
1 = Flag Capture Area 1 (Allies advanced spawn)
2 = Flag Capture Area 2 (Allies secondary advanced spawn)
3 = Flag Capture Area 3 (Allies and Axis SHARED secondary spawn ... usually the center flag)
4 = Flag Capture Area 4 (Axis secondary advanced spawn)
5 = Flag Capture Area 5 (Axis advanced spawn)
X = Axis Base

Allies Base

In the area that the Allies are going to start in we are going to place some spawnpoints

Right click in the 2d grid in the general area that you want to place a spawn and select mp --> uo_spawn_allies

Press "N" to bring down the entity editor and enter the key / value pair
script_gameobjectname / dom

*This makes it so that these spawns are used in the dom gametype

Position the spawn where you want it and use the spacebar to replicate it, placing spawns around the base (I create between 6 and 10...it will all depend on how many people your map is designed for)

Now we have our Allies Base ready...

Axis Base

In the area that the Axis are going to start in we are going to place some spawnpoints

Right click in the 2d grid in the general area that you want to place a spawn and select mp --> uo_spawn_axis

Press "N" to bring down the entity editor and enter the key / value pair

script_gameobjectname / dom

*This makes it so that these spawns are used in the dom gametype

Position the spawn where you want it and use the spacebar to replicate it, placing spawns around the base (I create between 6 and 10...it will all depend on how many people your map is designed for)

Now we have our Axis Base ready...

Creating The Flags

Neutral Flag

Locate the position in both 2d and 3d where we are going to place our first flag

Right click in the 2d grid and select script --> model

For simplicity, we are not going to browse for the xmodels, rather we are going to enter them manually, so close the xmodel browser.

Press "N" to bring down the entity editor and click on the model key

In the bottom of the entity editor where it says Value enter this information...
xmodel/mp_ctf_flag_gmi60
overwriting what is existing...so that your key / value pair will be as follows

model / xmodel/mp_ctf_flag_gmi60

Now enter the key / value pairs

script_gameobjectname / dom
targetname / flag1_neutral

Axis Flag

Now, without deselecting anything, press the spacebar and position the replicated flag over the first one

Press "N" to bring down the entity editor and click on the model key

In the bottom of the entity editor where it says Value enter this information...
xmodel/mp_ctf_flag_ge60
overwriting what is existing...so that your key / value pair will be as follows

model / xmodel/mp_ctf_flag_ge60

Now click on the targetname key

In the bottom of the entity editor where it says Value enter this information...
flag1_axis
overwriting what is existing...so that your key / value pair will be as follows

targetname / flag1_axis
script_gameobjectname / dom

Allies Flag

Now, without deselecting anything, press the spacebar and position the replicated flag over the first one

Press "N" to bring down the entity editor and click on the model key

In the bottom of the entity editor where it says Value enter this information...
xmodel/mp_ctf_flag_usa60
overwriting what is existing...so that your key / value pair will be as follows

model / xmodel/mp_ctf_flag_usa60

Now click on the targetname key

In the bottom of the entity editor where it says Value enter this information...
flag1_allies
overwriting what is existing...so that your key / value pair will be as follows

targetname / flag1_allies
script_gameobjectname / dom

Flag Capture

Load the Clip Texture by clicking Textures --> Common --> Clip

Set your Grid on Grid8 (which is 4 units per grid)

Drag out a clip brush that is 16 x 16 x 128

Position this clip brush over the staff of the flag pole so that the tops are even (the top of the clip is even with the top of the flag pole), and the flag pole is centered in the clip brush

With the clip brush still selected, right click in 2d script --> brushmodel

Press "N" to bring down the entity editor and enter the key / value pair as follows

script_gameobjectname / dom

Creating the Capture Area

Load the Trigger Texture by clicking Textures --> Common --> Trigger

Drag out a trigger brush that will be the area in which the player must be within to capture the flag (the size can be as large as you want, but try and think of gameplay and realism)

Make sure that your flag is completely within the trigger area and is relatively centered in the top (z) view

With the trigger brush still selected right click in the 2d view and click trigger --> multiple

Press "N" to bring down the entity editor and enter the key / value pair as follows

script_gameobjectname / dom
targetname / flag1
target / flag1_spawn_group

* The reason that we give them targets is to open up new (associated) spawn points once certain flags are captured, and remove those spawn points availability when the flag is lost

Creating Flag Areas 2 through 5

If I were to go through this process completely, step-by-step, the information would be both repetative and make this tutorial way longer than neccessary, so...

Follow the above information, changing all instances of flag1 to the flag area number you are creating

Here is a quick rundown on the flag 2 area changes in values

Neutral Flag
targetname / flag2_neutral

Axis Flag
targetname / flag2_axis

Allies Flag
targetname / flag2_allies

Capture Area
targetname / flag2
target / flag2_spawn_group

The rest of the values stay the same

Creating Advanced Spawn Points

These will be the spawnpoints associated with the capture or loss of each (Allies / Axis) advanced flag (the one closest to their respective bases)

We are going to assume that the flag you just created is the one that is closest to the Allies Base (#1 in the map layout) - so we will create advance Allies spawnpoints off of this one

In the area that you want a spawn to be created that will be relative to the capturing or loss of flag1 right click in the 2d window --> mp --> uo_spawn_allies

Press "N" to bring down the entity editor and enter the key / value pair as follows

script_gameobjectname / dom
targetname / flag1_spawn_group
 
Press the spacebar to replicate this spawn point and move to another position you want associated with this flag capture...repeat as many times as you want

It is important to note that only Allied Players will be able to spawn from this location, as it would be rather unfair to have Axis Players spawning behind captured areas, and likewise with any Axis advanced spawns that you create

Repeat this for capture area (flag) #5, but use uo_spawn_axis for the spawns and change the targetname to flag5_spawn_group

Creating Secondary Advanced Spawn Points

These will be the spawnpoints associated with the capture or loss of each (Allies / Axis) secondary advanced flag (the one second closest to their respective bases)

We are going to assume that the flag you just created is the one that is closest to the Allies Base (#2 in the map layout) - so we will create secondary advance Allies spawnpoints off of this one

In the area that you want a spawn to be created that will be relative to the capturing or loss of flag2 right click in the 2d window --> mp --> uo_spawn_allies_secondary

Press "N" to bring down the entity editor and enter the key / value pair as follows

script_gameobjectname / dom
targetname / flag2_spawn_group

Press the spacebar to replicate this spawn point and move to another position you want associated with this flag capture...repeat as many times as you want

It is important to note that only Allied Players will be able to spawn from this location, as it would be rather unfair to have Axis Players spawning behind captured areas, and likewise with any Axis advanced spawns that you create

Repeat this for capture area (flag) #4, but use uo_spawn_axis_secondary for the spawns and change the targetname to flag4_spawn_group

Creating The Shared (Center) Secondary Advanced Spawn Points

This would be the TSN Turning Point of the game...

These will be the spawnpoints associated with the capture or loss of the center flag

Unlike the previous 2 flag capture points - this one will have spawnpoints for both teams

In the area that you want a spawn to be created that will be relative to the capturing or loss of flag#3 right click in the 2d window --> mp --> uo_spawn_allies_secondary

Press "N" to bring down the entity editor and enter the key / value pair as follows

script_gameobjectname / dom
targetname / flag3_spawn_group

Press the spacebar to replicate this spawn point and move to another position you want associated with this flag capture...repeat as many times as you want

Now, right click in the 2d window --> mp --> uo_spawn_axis_secondary

Press "N" to bring down the entity editor and enter the key / value pair as follows

script_gameobjectname / dom
targetname / flag3_spawn_group

Move this spawn so that it is occupying the same space as an Allied spawn associated with flag#3

Press the spacebar to replicate this spawn point and position the duplicate over the next Allied spawn....repeat until you have and allied and axis spawn in each location you wish to spawn players from when the middle flag is in their possession

Inserting the Intermission

As with all gametypes, there is a requirement that at least one DOM intermission be placed somewhere in your map

.gsc Requirements

The .gsc level requirements for DOM are really quite simple, and are probably covered in your .gsc by another gametype...but just in case - here they are:

Team Definitions:
game["allies"] = "american";
game["axis"] = "german";
This sets the nationalities of the teams. Allies can be american, british, or russian. Axis can be german.

If using minefields or exploders:
mapsmp\_load::main();

I hope this helps you with your DOM
StrYdeR

Sample .map

ShosMeister has put together a sample .map using the above tutorial, and you can get it here