大家给看看FLUX2D的英文帮助，这一段没看懂，不知它说什么

freeshierly

我在学FLUX2D的induction heating例子，在第4.9.9节讲到了Orient the lines，似乎是给线定位，然后给出了下面一段解释，line的方位和node还有关系，如果不合适的话呢，还需要把显得方向反过来？没看明白，大家给个解释吧！

谢谢！

When a mesh line characterized by a geometric distribution of nodes is assigned to a line,Preflux 2D arbitrarily orients the line in order to concentrate the nodes towards an end. If the chosen end is not appropriate, the orientation of the line must be reversed.