How to find the direction to translate an object, to move towards a point, regardless of rotation?

Questions & Answers
1

I have two objects. A and B.
A moves around freely (A player.)
B is an object which simply moves around based on a 'movement vector" , that is, a “horizontal” and “vertical” vector (NOT one fed in by the keyboard).

So, naturally, that “movement vector” is relative to B’s rotation (i.e, “(0 , 1)” will move it forward)

I need to calculate that “movement vector” based on a “destination node” (which is calculated by a timer).
I could just say “look at the node, and move forward”
But, I need B to move towards the node even if its transform.forward changes.

I thought I just needed to multiply a direction vector by transform.forward of B. But I’m dumb! Thanks in advance for any help.

2

If you know the destination and where you’re starting from, you can do this with basic vector math.

// Where you're starting
Vector3 source = new Vector3(0, -10, 20);

// Where you're going
Vector3 destination = new Vector3(10, 20, -5);

// Difference vector
Vector3 delta = (destination - source);

// Direction and distance
Vector3 sourceToDestination = delta.normalized;
float distance = delta.magnitude;
3

The following function will give you the direction vector in the local space of the given transform.

Vector3 GetLocalDirection( Transform transform, Vector3 destination )
{
    return transform.InverseTransformDirection( (destination - transform.position).normalized );
}

You can use it as follow:

gameObjectB.transform.Translate( GetLocalDirection( gameObjectB.transform, destinationNode.transform.position ) ) ;