If every hinge point of a fold in profile are connected, we can get an imaginary plane which divides the fold symmetrically. This imaginary plane is known as axial plane. The geometrical characteristics are used to classify folds.是什么意思_If every hinge point of a fold in profile are connected, we can get an imaginary plane which divides the fold symmetrically. This imaginary plane is known as axial plane. The geometrical characteristics are used to classify folds.在線翻譯_英語_讀音_用法_例句