拱形截面沿纵向连续成面

提示词

把已选拱形截面沿给定纵轴和长度连续延伸成筒拱，拱顶线、两侧拱脚线和端部截面相互对应；保留连续曲面，不换成一排独立拱门或平折屋面。

Extend the selected arch section continuously along the supplied longitudinal axis and length to form a barrel vault. Keep the crown line, both springing lines and end sections corresponding, retaining a continuous curved surface rather than separate arches or a folded roof.