The question arose if a kill boundary could be used as a wall, and if it
could be removed during game play. From my answer I thought this was a
very good question to explore while discussing how Safe Boundaries and
Kill Boundaries are used in forging Reach.
When a forger places a Safe Boundary onto a map, they are defining the
boundaries of the playable area on the canvas. They are restricting the
playable area to the volume that the Safe Boundary occupies. Multiple
Safe Boundaries define the playable area(s), whether they are contiguous
or not.
It does not matter if only one Safe Boundary is placed on the canvas, or
multiple Safe Boundaries are placed on the canvas. If a Safe Boundary
exists on the canvas, then anywhere outside of a Safe Boundary is
outside the playable area.
The default behavior (e.g., when no Safe Boundary is used) for any canvas is to make the entire canvas the playable area.
The Safe Boundary is invisible during play, but its affects are very
real to the player. There are two types of Safe Boundary - the Soft Safe
Boundary and the Safe Boundary (which we will refer to as Hard Safe
Boundary for the rest of this article). They both define the area that
is playable, but they convey that information to the player in different
ways.
When a player leaves a Soft Safe Boundary, they get a warning that they
must return to the battle area (the playable area of the map). This
warning continues for 10 second. At the end of that time, the player
dies. When a player leaves a Hard Safe Boundary, they die immediately.
Since the warning or immediate death occurs when leaving the Safe
Boundary, if a canvas has both a Soft Safe Boundary and a Hard Safe
Boundary, then they are all treated as Hard Safe Boundaries. That is, if
leaving one Safe Boundary causes immediate death, then leaving any Safe
Boundary will do the same. It is not clear if this was by design (to
maintain consistency in leaving the playable area) or a side effect.
Kill Boundary
Kill Boundaries come in two flavors also, again a Soft Kill Boundary and
a Kill Boundary (which we will refer to as Hard Kill Boundary for the
rest of this article). However, their effects are noticed when a player enters
the Kill Boundary. As their names imply, entering a Soft Kill Boundary
provides a 10 second warning that the player has exited the playable
area; entering a Hard Kill Boundary is instant death.
The main purpose of a Kill Boundary is to define areas that are not playable; areas that are out of bounds during game play.
The main purpose of the Soft Kill Boundary is to warn the player that
they have left the playable area and must return immediately. This is
akin to the Guardian on Halo 3 maps, when you step outside the central
area of the map.
The main purpose of a Hard Kill Boundary is to speed up the death of a
player that has ventured out of the playable area so far that they
cannot return and will certainly die. After all, who wants to wait 10
seconds at the bottom of a cliff, alive, but not able to rejoin the game
in progress?
Soft Kill Boundaries do not turn into Hard Kill Boundaries when a Hard
Kill Boundary is also present on a map. Having both types can be useful
on many maps.
Finally, where Safe Boundaries and Kill Boundaries overlap, the Kill
Boundary overrides the Safe Boundary. Without any Safe Boundaries on the
canvas, Kill Boundaries define the areas not in the playable area of
the map, though the entire canvas is otherwise the playable area.
Soft Kill Boundaries are used quite frequently to make specific areas
off limits within a Safe Boundary. For example, a forger may wish to
keep players from camping on roofs or pillars. A Soft Kill Boundary on
top of a roof gently notifies the player that they should get back down
to the playable area.
Spawning Safe And Kill Boundaries
Safe Boundaries and Kill Boundaries cannot be spawned during game play,
but they can be gated out of the map during Invasion game phase changes.
Emulating the Spawning of a Safe Boundary
Since Kill Boundaries overlapping Safe Boundaries override the Safe
Boundaries, one can emulate the spawning of a Safe Boundary by
overlapping it with a Kill Boundary, then gating the Kill Boundary
during a phase change. When the Kill Boundary disappears, the Safe
Boundary will appear to have spawned. Really, its effects will begin to
appear for the players to experience.
In an Invasion game, emulating the spawning of a Safe Boundary
essentially grows the playable area as the round progresses. Likewise,
gating Safe Boundaries shrinks the playable area as the round
progresses. Using both in a single phase change can effectively shift or
move the playable area across the canvas. But care must be taken, as
players may still be in a playable area when it becomes out of bounds.
This will almost certainly be unintuitive to the player and a point of
frustration (a very bad thing for any forge work).
Emulating the Spawning of a Kill Boundary
Remember, anywhere outside a Safe Boundary is the same as being in a
Kill Boundary, if and only if a Safe Boundary exists else where on the
canvas? Well, by gating one Safe Boundary off the canvas while a second
Safe Boundary remains else where, the space occupied by the first Safe
Boundary is now out of bounds. It will appear to those players in the
Safe Boundary that a Kill Boundary suddenly appeared over them.
The type of Kill Boundary experience will be dependent upon the type of
Safe Boundaries used. If one of them is a Hard Safe Boundary, then the
experience will be that players will suddenly die. If they are all Soft
Safe Boundaries, then the experience will be that the players will
linger for 10 seconds to their death if they cannot get to another Safe
Boundary quickly.
Kill Boundaries As Walls
A Kill Boundary could be used as an invisible wall. But it should never be used in this capacity for several reasons.
First, it is not a wall, but an engine influence zone. Trying to make a
wall out of a non wall is often plagued with problems for the game
experience.
Additionally, it is invisible. Can you imagine the frustration a person
would have if they did not see a wall, but instantly died from walking
into it? One of the key rules to any good forged work is that the map
must never be frustrating or confusing.
Also, if you use a Soft Kill Boundary as a wall, your players won't
experience a wall, but will experience an out of bounds message on their
screen. Again, the experience that your players receive is not the
experience of a wall.
Spawning Out Of Bounds
Setting up respawn points (or zones for Invasion) within a Soft Kill
Boundary can have the effect of motivating the players to move quickly
to the playable area. But the problem with this approach is simply that
it is generally unintuitive that someone would even spawn outside the
playable area. It is my observation that this type of spawning technique
is not well received by most players.
Some players have a natural desire to explore. This technique eliminates
any opportunity for a player to explore the area they spawn in, for
weapons, vehicles, or other features built into the map.