不过，多重视点对沿特定轴线精确对齐对象还是有帮助的。
Nonetheless, multiple viewpoints are helpful for precisely aligning objects along a particular axis .
当被测要素为轴线、中心线或对称平面时，指引线的箭头和基准符号应与该要素的尺寸线对齐。
If the element being tested with tolerance requirements is an axis, centre line or symmetrical plane, the arrow and datum symbol should be aligned to the dimension line of that element.
应用推荐