1 Information
Despite being a full 3D RTS-FPS hybrid game with full physics for all game objects, Urban Assault engine is quite robust and permits the players to create a huge number of units without imposing much restrictions or a significant loss of performance during the gameplay. This is especially true for single-player mode, where the unit limit for the players in a standard sense virtually does not exist at all, and players can create as much units as they wish.
Thanks to this generous design, the players are practically allowed to create as much units until the game becomes unstable. Additionally, this design also allows inexperienced players to complete missions through outnumbering the AI enemies via sheer brute-forcing of unit counts even when their strategy did not work. However, there are unit limits in multiplayer mode, where the general performance and balance of the online match are the main priority.
2 Single-player
2.1 User
There is no unit limit placed on the player in single-player mode. Therefore, the player's host station can virtually create any numbers of units until the game engine becomes unstable. Also in single-player mode, the individual unit costs for the player are also static and do not increase as well, regardless of how many units are currently under the control of the player.
2.2 AI
On the contrary, the AI players in single-player mode are subject to a unique AI energy upkeep/maintenance mechanics, whose design is deliberately intended to gradually hamper the capacity of the AI host stations at creating additional units once they have numerous units and flaks under their control, by dynamically increasing the creation costs for any extra units.
Unlike the player host station, the energy costs of units for AI host stations are fully dynamic and directly based on total counts of units that are currently under the command of the AI host station. The more units that an AI host station already controls, the more expensive it will be to create any extra units. This system is somewhat similar to the Multiplayer unit limit.
This AI-exclusive mechanics serves two main purposes: It helps inexperienced players by limiting the practical number of units that a hostile AI host station can control at a given time, while also keeping the numbers of units that AI create in check for the game's performance. Since this is not a hard limit, the practical limit depends on level parameters of AI enemies.
The detailed upkeep/maintenance mechanics for AI players will be covered in a separate Energy Math article.
3 Multiplayer
In multiplayer mode, there are different types of unit limit system intended for levels and connection methods. The type and size of the unit limit is defined per each level data script file.
The detailed unit limits mechanics is fully explained in the official Multiplayer Notes game document file.
3.1 Official Multiplayer Notes
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4. UNIT LIMITS
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There are two types of unit limits that you will encounter in multiplayer
games. One is the "hard" limit type, for low-bandwidth games (these levels
are indicated by telephone icons on the Level Selection screen), and the
other is the "soft" limit type, for high-bandwidth games.
Hard Limit
The hard limit is pretty basic. Once you reach the hard limit, you will no
longer be able to create any additional units until those that have already
been created are destroyed. The hard limit is used for low-bandwidth levels.
Soft Limit
The soft limit works on the idea that the more units you create the less
efficient your energy absorption rate becomes (see your printed documentation
and online Help for information on the Energy Manager and resource management).
Once you reach the soft limit, every unit you create over the limit causes
your energy efficiency to drop by 5% (you may not notice this if you have
already had the good fortune to conquer numerous sectors). The way to return
your energy efficiency back to 100% is to either conquer more sectors or
destroy your other units.
3.2 Effects
The unit limits in the multiplayer mode serve similar functions as the other RTS games: Straightforward balance reasons to prevent excessive snowballing or spamming, as well as keeping the game's performance in check by limiting the total numbers of available units at a time, which is especially important in online multiplayer matches.
4 Notes
The default Unit Limit in multiplayer mode is Soft Limit of 80 units for the majority of normal multiplayer levels, and Hard Limit of 12 units for the 'slow_connection' (Modem) levels.