What we will do is just, at every point along the curve, the dot product between the vector field and the normal vector.

我们要做的是，沿着曲线的每一点上，取向量场和法向量的点积。

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And, in some cases, for example, if you know that the vector field is tangent to the curve or if a dot product is constant or things like that then that might actually give you a very easy answer.

例如，在某些情况下，如果已知向量场与曲线相切，或者内积是一个常数等等，那么结果将会很简单。

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A quadratic bezier curve has a start and an end point (blue dots) and just one control point (red dot) while a cubic bezier curve USES two control points.

它们都有一个起点一个终点图中的蓝点，但二次方贝塞尔曲线只有一个红色控制点点而三次方贝塞尔曲线有两个。

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