1·Well, you know the normal vector.
那么当然知道它的法向量。
2·What is the normal vector?
那么法向量又是什么呢？
3·Why would we ever know a normal vector?
为什么我们会知道法向量？
4·Why else would you know a normal vector?
还有什么原因你会知道法向量？
5·That means your normal vector points down.
那意味着法向量指向下。
6·The normal vector will just be the gradient.
法向量就是梯度向量。
7·That corresponds to normal vector pointing up.
那相当于法向量指向上。
8·But you can also just stay with a normal vector.
但是你也可以继续只用法向量的。
9·And that is, in general, not a unit normal vector.
这通常不是一个单位法向量。
10·Now, let's multiply that by the unit normal vector.
现在用单位法向量乘以那个。