A normal line.

一个普通行。

Normal line map is taken instead of the 2D map in order to reduce the capacity of model.

采用法线贴图代替平面贴图的方法，减小模型容量；

The error can be avoided by increasing the gear grinding allowance in length of common normal line to grind gear.

此误差可通过在公法线长度方向上加大留磨量，进行磨齿予以消除。

The algebraic sum of the product of any point on a closed curve and the distance from this point's normal line to a fix point is zero.

任意闭合曲线上的点与该点法线到某定点距离的乘积，其代数和为零。

And with head tracking available, placement options are increased: the UI can be placed to the user's side, or above the normal line of sight, for instance.

由于具有头部跟踪可用，需要增加放置选项：比如，UI可以放置到用户的一侧，或在正常视线之上。