For a designer symmetry can make life a lot easier, only having to design one side of a map and than being able to mirror it saves a lot of time. The designer would than have to create a specific art style for both sides to make it clear whose side you were on, to go for an easy example a red or blue team. Whereas one side would perhaps use a lot warmer colours on the higher end of the colour spectrum, and colder lower colours for the blue team. To differentiate the sides more different props and models can be added to the level, as long as these do not give any other tactical advantages like a higher view point or a better hiding place, generally in a symmetrical level if you can hide behind something one one side, you can probably hide in a similar spot on the other.
Team Fortress 2 uses a cold industrialised colour scheme to represent one team, and a warm rustic feel for the other.
Team Fortress 2 (2007) Valve Corporation
Of course this doesn't correlate to a real environment and could perhaps take some of the immersion out of the game, it is very rare that any natural environment is symmetrical. Asymmetrical maps usually have asymmetric game modes to go with them, usually with one team defending with another attacking, and in some cases one team usually have a very slight advantage, for example higher ground, or more cover. Symmetric maps generally have symmetric games modes, where both teams have the same objective, capture the opponents flag, capture the neutral point, etc. Even modern games that try to aim to have more natural environments use symmetry to make their levels fair, this is something that I hope to break, or if I can't at least solidify the fact that for a map to be competitive and fair it has to be symmetrical.
After the proposal has been handed in and marked I will upload it onto here to give a more grounded idea of the project in the near future.
