/// @brief Orientation of OBB. axis[i] is the ith column of the orientation matrix for the box; it is also the i-th principle direction of the box.
/// We assume that axis[0] corresponds to the axis with the longest box edge, axis[1] corresponds to the shorter one and axis[2] corresponds to the shortest one.
/// @brief Orientation of RSS. axis[i] is the ith column of the orientation matrix for the RSS; it is also the i-th principle direction of the RSS.
/// We assume that axis[0] corresponds to the axis with the longest length, axis[1] corresponds to the shorter one and axis[2] corresponds to the shortest one.