i want to move units at a line between to vectors. If i want to set them in more than one row, i dont know which direction i can give them, and how to shift every single point on row to a valid position behind a given vector

Video of bug result now

Video of point that should always be behind the destination points

at the second video you can see that at specific movements the red points are correctly calculated. but i i drag from left down to right up its nearly the same than the green destinations

You need to find a perpendicular vector to use. I take it you have a mouseDown and mouseUp position, then you need to find a vector perpendicular to this, which you can do using Vector3.Cross which will give the cross product of two vectors: