| 摘要 |
PROBLEM TO BE SOLVED: To provide a shape material easily and inexpensively twistable without collapse of a hollow portion even when having a ridge or a flat hollow shape.SOLUTION: A shape material, in which a sectional outer circumference is noncircular, has a hollow portion 2. An inner circumference of the hollow portion 2 is almost circular and a center O of the hollow portion 2 agrees with a sectional center of the shape material 1. The shape material is twisted with the center O of the hollow portion 2 as an axis. |
