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Invasion Spawning

A look at setting up a spawn system to provide a unique experience with Invasion, to support the story line, to promote team work, and cover the basics of Invasion, Invasion Slayer, and Bro Slayer. (Updated with the Invasion Mini Lessons.)


I have written articles on the classic spawn system used in most game types already. This article compliments the previous ones by discussing the spawn engine used for Invasion, Invasion Slayer (and Invasion Skirmish), and now Bro Slayer. For these game types, the player chooses where to respawn; the spawn engine merely assists the player in the process, nothing more.

This article shall discuss the basics of this spawn engine, then particulars for Invasion Slayer and Bro Slayer. Then it will discuss how to use the spawn engine for Invasion. This last point is of greatest interest for Invasion forgers, because unlike any other game type, a good Invasion game experience is based upon a strong story line. For a better understanding of what is to be accomplished by Invasion spawning, I recommend the reader look through the Forging Invasion lessons, especially
Fire Teams and From The Spawn.

While discussing the spawning aspects of the Invasion game type, other aspects of setting up an Invasion game type will be discussed, but only to clarify or help with examples dealing with player spawning. The full scope of setting up an Invasion game type to support a story line is well beyond the scope of this article.


All three of these game types have the following features in common.

Initial Spawn Points
are used to identify where a player will spawn the first time they spawn during a round. This is true even if they enter a game in mid round.

The forger can include enough Initial Spawn Points for each side so that initial spawning can never fail.

Respawn Zones
are used to define where a player will respawn. This is not the classic Respawn Zone object from the forge palette (weak, anti, or strong), but a zone that is created by setting an object’s Game Type Label property to a specific value. This is a completely different role for the Respawn Zone than in the classic spawn system, where Respawn Points define where a player can respawn and the Respawn Zones gave weight to those Respawn Points. The concept of weights becomes irrelevant, because the spawn engine is not responsible for selecting where the player respawns.

Covering a Respawn Zone with any type of classic Respawn Zone, Weak Respawn Zone, Anti Respawn Zone, Kill Zone, or Safe Zone has no affect on allowing the spawning player to select the Respawn Zone when respawning.

The typical and recommended method of defining a Respawn Zone, particularly for Invasion maps, is to use Hill Marker objects and assign them with an appropriate Game Type Label property. Hill Markers are invisible during game play; are particularly useful in Invasion games where numerous Respawn Zones may be necessary; but most importantly, their orientation is obvious in forge, so you know which way the person will face initially when spawning in the zone. For the remainder of this article, the term Respawn Zone shall not refer to the actual Respawn Zone object types in the palette, but rather those objects used to form Respawn Zones (e.g., Hill Markers).

Other forge objects can be used as the Respawn Zone object. On the other hand, Respawn Points cannot be used to act as Respawn Zone objects. Additionally, if a moveable object, such as a crate, is used as a Respawn Zone object, then the Respawn Zone will move with the object itself. For Invasion, this would generally be unacceptable.

The spawning system is based upon a team centric model. None of these game types support FFA. You cannot start a game with any team assignment other than blue or red. Team assignment of Initial Spawn Points and Respawn Zones is necessary. Anything other than Red and Blue Initial Spawn Points and Respawn Zones are considered invalid, and the resulting behavior is undefined.

Fire Teams is a new concept introduced by Invasion and Invasion Slayer, but is not present in Bro Slayer. The spawn engine will assign each player to a Fire Team in what appears to be a sort of round robin fashion[1], in an attempt to even out the fire teams.

In some game types, Fire Team assignments are honored by the Initial Spawn Point and also the Respawn Zone. Fire Team assignment is accomplished by adjusting the Spawn Sequence property of the Initial Spawn Point or Respawn Zone to the Fire Team’s identifier. The value of 0 is the first Fire Team; 1 is the second Fire Team; and 2 is the third Fire Team. Any other value matches to all Fire Teams. 

If a Fire Team has no assigned Initial Spawn Point, they will use any available Initial Spawn Point assigned to their team. If a working respawn zone for a fire team does not exist and the player spawning has no Fire Teammate, then they could possibly spawn anywhere on the canvas, even outside the play area. 

Invasion Slayer

The concept of Invasion Slayer is based upon the slayer goal of body count, with the dynamic introduction of weapons and vehicles during game play. To make an Invasion Slayer game, you need to have Initial Spawn Points for each team member, and at least one Respawn Zone for each team. The Respawn Zones’ Game Type Label property must be set to INV_SLAYER_RES_ZONE. Initial Spawn Points honor Fire Team assignments, but Respawn Zones do not. [2] The spawn engine will allow a player to also spawn at the location of his Fire Team members.

A map spawn layout for Invasion Slayer can benefit from multiple Respawn Zones for a spawning player to choose from – the more Respawn Zones, the more opportunities to find a safe place to respawn. Remember, a player has only his Fire Team members to spawn with during game play, and that if the Fire Team members are still alive. By adding additional Respawn Zones to the map, the forger can reduce or possibly even eliminate spawn camping.

From a spawning perspective, Invasion Skirmish is the same as Invasion Slayer, but for maps that do not include vehicles.


Bro Slayer

The concept of Bro Slayer is more of a dumbed down version of Invasion Slayer. It does not include weapon drop zones, and it does not include Fire Teams. A player can respawn at any of his teammates’ locations and in any of his team’s assigned Respawn Zone. The Respawn Zones’ Game Type Label property must be set to BRO_SPAWN_LOC.

A map spawn layout for Bro Slayer can benefit from multiple Respawn Zones for a spawning player to choose from, much as Invasion Slayer can benefit. However, compared to other game types, Bro Slayer has the more built in opportunity to respawn, since a player can respawn with any of his teammates.


The Invasion game type spawn setup rules are a straight forward superset of the preceding rules. What is unique about Invasion games is that a single round consists of three phases. Each phase is like a mini game that each side tries to win. For a successful Invasion game, the three phases must flow fluently together. This is where a story line comes in – to provide the cohesion between the phases. Without a story line of some kind, the forger risks creating nothing more than three disconnected mini rounds that do nothing more than run back to back to each other.

A simplistic spawn design by the forger can dilute the game play experience and even cloud the story line. It is extremely necessary to support each Fire Team as an individual team (see Fire Teams for more information).

Each Species has three Teams called Fire Teams. Each Fire Team consist of two players paired up by the spawn engine. Game play does not require that each pair of Fire Team partners function as a Fire Team, but the benefits provided by the spawn engine tend to give value to such a strategy. Fire Team assignments are honored by both Respawn Zones and Initial Spawn Points.

An Invasion map requires at least six Initial Spawn Points for each Species. Fire Teams' Initial Spawn Points are grouped in locations distant from and out of line of sight from each other in most cases and should have four Initial Respawn Points per Fire Team (see Forging Forge Objects for details).

For respawning players, there are two types of Respawn Zones that can be used in Invasion game play –
Backfield and Phase.

Backfield Respawn Zones

The Backfield Respawn Zone provides an entire team with a specific place to respawn during the round regardless of the phase. This is typically used where a player may wish to respawn at a vehicle spawn location. The Game Type Label to assign to the Backfield Respawn Zone is INV_RES_ZONE.

Typically, the Backfield Respawn Zone is used for the second and third phases of the round. To introduce a Backfield Respawn Zone onto the map at the start of the second phase, set the spawn sequence to 2; the start of the third phase, set the spawn sequence to 3. Once the Backfield Respawn Zone is spawned onto the map, it remains for the rest of the Round.

Phase Respawn Zones

The Phase Respawn Zone provides a Fire Team or the whole team with a location to respawn during a specific phase of the game. The location itself is generally key to promoting both the Fire Team’s role within the team as well as the story line.

To assign a Respawn Zone to phase 1, 2, or 3, change its Game Type Label property to INV_RES_P1, INV_RES_P2, or INV_RES_P3, respectively. To assign a Phase Respawn Zone to a specific Fire Team, change its Spawn Sequence property to the Fire Team’s identifier 0, 1, or 2; or to 3 for all Fire Teams.

A Phase Respawn Zone can be assigned to the whole team and used as a team’s common respawn area in an optimal location for the given phase. A general staging area where weapons or vehicles are available for the given phase is a good example. But typically, each Fire Team is given their own Respawn Zone, even when they are within a few steps of each other.

Having more than one Fire Team compatible Phase Respawn Zone (those assigned to the Fire Team or to the entire team) provides a player with more spawn locations to choose from. This configuration can yield a safer respawn experience overall, but typically a player trying to spawn onto the map does not have more than two or possibly three locations to choose from.

Delayed Respawn Zones

Delaying the spawning of a Respawn Zone onto the map by using its Spawn Timer property is an undefined behavior. While tests have shown that it can work, it has severe limitations that prevent consistent behavior, and thus should not be utilized.

Promoting Team Work and Story Line

It is possible to promote unique Fire Team roles in an Invasion game by having each Fire Team spawn in a unique and isolated location where power weapons spawn. But as a rule, an Invasion map should allow all three Fire Teams to spawn where vehicles spawn.
For example, by providing a single Fire Team the exclusive opportunity to respawn at a sniper that oversees the battle field, the forger grants that Fire Team the opportunity to play out the exclusive role necessary to provide cover support for their team’s infantry. This forces the Fire Team’s members to choose between the conventional battle field infantry role and the uniquely powerful support role that is for their Fire Team alone. This approach helps define which Fire Teams are primarily infantry and which are cover support roles. And it requires the Fire Team members to accept and play out the team work and story line as the forger intended, lest they risk losing the game.

By definition of the rules, the defender is favored. If the defender wins only one of the three phases, the defender wins the round. Therefore, the attacker should be favored with a slight edge in all the fighting. The forger can utilize the Respawn Zones to give this slight edge at any time during the first three minutes of any phase. In the example of one Fire Team having exclusive access to a sniper, that sniper can be setup to spawn 2 minutes into the phase. This way, the forger is giving that extra edge to the attacking team only if they need it – that is, if they have not won the phase already and time is running out. The maximum spawn time for any weapon is 2 minutes. Given a 4 minute phase, the forger could make the sniper available to one of the attacking Fire Teams during the last half of the phase.

Having said all that, one should note that power weapons typically spawn within the first minute of a phase.


The use of the Fire Team Phase Respawn Zones should never interfere with nor break the cohesion of the Invasion story line, but rather support and enhance it. The forger should have his Invasion map respect the Fire Teams as individual teams, a total of six teams among two Species. Careful application of Respawn Zones can yield unique and interesting game play.


[1] It was initially believed that players were assigned to Fire Teams in a round robin schedule, beginning with Fire Team 1 (Spawn Sequence property value 0). Recent tests have conclusively demonstrated that any Fire Team can be chosen for odd players. Rather than Fire Team populations of 2, 1, and 1, you could just as well see 1, 1, and 2. (But you should never see 1, 1, and 3.)

[2] According to Bungie, Respawn Zones honor Fire Team assignments in Invasion Slayer. However, in every test, a player could select between each Respawn Zone regardless of their Fire Team assignments. This may be due to an incorrect test case, but it is unlikely. I am currently awaiting word from Bungie on this issue.