The RM Bridge model in Modeler is created with the assumption of one of the three possibles Cross-section planes for the elements in Elevation:

• Normal to element axis in Elevation: perpendicular to the defined local element axis, i.e., in the Local Y-Z plane
• Vertical in Elevation: in the Global X-Y plane
• Horizontal in Elevation: in the Global X-Z plane

The first option is the Default selection and it's commonly used, for example, as shown below for the arch rib. 

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Like in the figure below, for the arch spandrel at the bearings area, it can also be the case that the engineers want the model to have a Vertical CS and ignore the slope for the Cross-section plane positioning. Or to have a Horizontal CS, and ignore any possible angle in vertical elements. These other possibilities are useful for modeling specific situations, for example, inclined piers, pre-camber, etc.

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