The program begins to draw a polyline when it finds a point with its code ending in S (space followed by the letter S), which indicates the beginning (Start). It will continue drawing vertices as it finds points with the associated code (consecutive or not, but respecting their order), and it will end the line when it finds a point with its code ending in E, which indicates the end, or another starting code. If the suffix is C, the polyline is closed with its first point. This process is repeated until the end of the file is reached. The lines are drawn depending on the order of the codes in the Code Database.

Example:

1 ROAD S

2 ROAD

3 ROAD

4 ROAD E

On the other hand, polylines can contain arc segments. To do this, the suffixes CS for the start point, CC for the intermediate points and CE for the end point must be used. See Surface Settings, Break Lines Coding button.