The local major and minor directions for a Section Cut are determined differently based on whether the Section Cut is oriented horizontally or vertically. For horizontal Section Cuts, the major direction is chosen in the direction of the longest contiguous horizontal segment of wall. More specifically, the Section Cut is rotated clockwise about the global Z-axis from its global orientation until the longest segment is parallel to the global X-axis (see Figure below).

For vertical Section Cuts, the local major axis coincides with the global Z-axis. The local minor axis is 90 degrees CCW from the local major axis.