Understanding RUL Flags

RUL files control the placement of network items in the game. An example of a network item is the road you drag out. RUL flags refer to a specific combination of hexadecimal values that tell each network tile what to do.

Understanding Flags #

Basic Flags #

Network flags are the game’s encoding of transit network connections for a given tile. Each tile has four flags, one for each edge. A flag defines whether a connection exists across an edge and its relative direction.

Five primitive flags are used in the various RUL files:

• 0 - no connection
• 1 - left diagonal
• 2 - orthogonal
• 3 - right diagonal
• 4 - median (for double-width networks, e.g. avenue)

Individual Network RULs make use of additional flags:

• 11 - left diagonal to orthogonal blend
• 13 - right diagonal to orthogonal blend

Rail networks use additional complex flags:

• 21 - left diagonal switch
• 23 - right diagonal switch
• 22 - left secondary blend
• 42 - right secondary blend
• 32 - left orthogonal to diagonal crossover/switch
• 52 - right orthogonal to diagonal crossover/switch
• 62 - wye flag (also used for crossover/switch)
• 72 - ‘W’ flag (used for ‘W’ switches)

Individual Network RUL (INRUL) #

Individual network RULs define the standalone behavior of the game’s twelve networks. Each network has a basic and advanced INRUL file. Basic INRUL defines typical placement, while advanced INRUL handles more complex situations.

INRULs are composed in a 5x5 grid of tiles in which flags and network piece IDs are defined. Conventionally, basic INRUL uses only tile to define a rule, while advanced INRUL defines multiple tiles.

Intersection Solutions RUL (RUL1) #

RUL1 defines tiles for the intersections between two different network types.

Override RUL (RUL2) #

RUL2 is used to override the results of INRUL and RUL1 definitions. It works by reassigning a pair of adjacent pieces to another pair, replacing one or both pieces. RUL2 is the mechanism used to create override networks such as SAM or RHW.

Intersection Ordering RUL (RUL0) #

RUL0 defines interchanges, puzzle pieces and FLEX-style pieces which can be placed using menu buttons.