There are two different types of coordinate systems used in Substructure: global and local coordinates. Global coordinates refer to the coordinate system for the entire structure, where positive X-direction is along the length of the pier cap (i.e., centerline) from the left end to the right end when looking the pier downstation, positive Z-direction is in the direction of stationing, and positive Y-direction is in the upward vertical direction. Global coordinates are the same for each of the three components of the structure, namely the pier cap, column, and footing. For a skewed bridge, the positive X-direction is along the centerline of the pier cap from left to right and the other two axes are oriented accordingly.