Game Development Reference
In-Depth Information
Interaction Model
For strategy games, the interaction model tends to be on a large scale. Rarely do you
find a strategy game with a single avatar, although the PC version of
Battlezone
(not
to be confused with the original coin-op) is a notable exception. Generally, the
player indirectly controls the units under his command while enjoying a godlike
view of the game world. The true interaction model, in this instance, is related to
the scale of the world. How many units does the player control? Is it a small squad,
or is it a large army?
The feel of a small squad is much more personal and intimate than a large army.
The player can explore the personalities of the units more and tends to care more
about the individual fates of his units. Also, with smaller groups, individual charac-
ters may improve their skills and abilities as the game goes along. The
X-COM
series
of games is particularly strong in this area—the player controls several small squads
of about 20 soldiers each, small enough so that the player can keep a handle on
each individual member. Incidentally, in these games, the player can also build up
a team of noncombat units by recruiting one at a time the scientists that research
the alien technology.
For larger-scale games, it is too hard for the player to keep track of every single unit
in the army, although some games do attempt this.
Civilization III
, for example,
allows units to upgrade from Recruit to Veteran to Elite status, a simple progression
that players can easily understand. Others, such as
Warcraf t III
, designate a small
number of units as Heroes. A Hero has special abilities and requires personal atten-
tion from the player. The player can easily focus his attention on the small number
of Heroes while treating the fighters in the other squads in the army as undifferen-
tiated groups.
Camera Model
For many years, computer strategy games displayed their game worlds in two
dimensions as seen from above, effectively treating the video screen like a map or a
tabletop game board. Later games adopted an isometric perspective in which build-
ings and units appeared to stand up above the surface of the landscape, although
the underlying model of the world was still 2D. With the arrival of 3D display
engines, strategy games began to include fully three-dimensional worlds with 3D
modeled hills, valleys, and other landscape features, as well as 3D modeled units.
Regardless of the display technology, players of strategy games need to see the big
picture, the overall view of the game world. The player cannot plan an effective
strategy if she is forced to view the world from one avatar point of view. Unless
you're trying to model what warfare was like for a general of ancient times—back
when generals fought alongside their troops—you should choose some form of aer-
ial perspective. The player will also find it valuable if you allow her some control
over the camera so that she can zoom out to see the whole battlefield or zoom in
