Knowing the points P1 and P2, I need the perpendicular direction vector (P1 and P2 are Vector3)

I try:

var direction = Vector3.Cross(P1, P2).normalized;

But that is not the correct answer.

How to do it correctly?

CodePudding user response：

It will be better if you write what you need more clearly, my reputation is not enough for writing comments so ı will just write here.

As ı understood you need a vector perpendicular to the line [P1, P2], but at 3 dimensions there is infinite number of perpendicular vectors to [P1, P2] (Imagine a perpendicular vector to [P1, P2] and rotate it in your mind. There will be infinite vector perpendicular to [P1, P2])

At 2 dimensions there will be just one perpendicular line for any line. İf the slope (Y/X) of a line is 3, the perpendicular line's slope will be 1/3.

If you want a vector perpendicular to two vectors (not dots) you can use the cross-product of two vectors. Cross product will give you a vector that is perpendicular to both vectors but it may not be what you want.

I don't know is there any built-in method for these. If you write why you need this it will be easy to help.

CodePudding user response：

So to do what you want to do, first you need to calculate the vector. You are passing 2 points as input when in reality you need 2 vectors. So first you should calculate the vector:

var direction = P2 - P1

After doing that, you can calculate the cross product:

var perpendicular = Vector3.Cross(direction, Vector3.Up).normalized;