Generates a 3D bridge with railing by extruding a floor plan polygon. Requires as input the bridge floor plan as a 2D feature polygon and an associated DTM and DOM as raster. The height of the bridge is determined from the DOM. If no thickness of the bridge is specified, it is derived from the bridge surface. The railing height is 1.0 m by default, the railing width is 0.35 m. No railing will be created if the railing height is set to 0, regardless of the specified railing width.