Cities in MM2 are created using several different files in different formats. This section gives a brief overview of these formats. For more detailed information, refer to the appropriate sub sections.

• Terrain (PSDL)

  Each city has one PSDL-file. This file defines roads, ground surface and buildings. In addition, the PSDL-file also provides an easy way to automatically place props along roads etc. This is particularuily good for placing street lights, parking meters and similar objects.

  The geometry of a city is divided into blocks. A block is a small section of the city, similar to the regular definition of a city block. One difference, though, is that roads and intersections are also placed in their own blocks.

  The block structure is used for all kinds of things in the game. Most obvious are visible surface identification, collision detection, ambient "intelligence", etc. All of these are calculated with respect of the block structure.

• Monuments (INST)

  Each city can have one INST-file. Stationary objects with detailed surfaces can be placed with an INST-file, in SF and London, this includes monuments, bridges, detailed buildings and parts of buildings such as facades with modeled balconies, subway entrances and more. The INST-file references a PKG-file for each object.

• Ambients (BAI)

  Each city can have one BAI-file. This file defines junction points and hermite curves for ambient traffic and pedestrians to follow. The BAI-file is also responsible for controlling the initial starting point of the cruise game mode.

• Props (PATHSET)

  In addition to the props placed automatically by the PSDL, each city can have one or more PATHSET-files. A PATHSET-file can place additional props in a city. A PATHSET-file provides several ways to efficiently place props that are not bound to a specific block.