Bridge path coordinate systems (BCS) provide a unique way to simplify the modeling of curved bridges. A BCS is a warped rectangular coordinate system whose axes are station, elevation, and transverse offset. The station axis follows the curved geometry of the bridge centerline, and automatic transformations convert BCS geometry to Cartesian coordinates
The horizontal geometry of the BCS is defined with stations and headings which can often be read off of design documents. BCSs allow the user to work in very simple coordinates despite any curvature of the structure by warping the usual x-axis into a curve that follows the curved center line of the bridge.
The warped "station (x) axis" is defined in two planes. Elevation and super elevation can be specified in addition to headings. Multiple bridge paths in the same project can be used to define girders, spiral on-and-off-ramps, and ground-level footings. These coordinate systems can also be used to specify joint coordinates and directions of supports, including for bearings and springs, and for the reporting of forces and other results.