How to cast ray from a object in direction local to that object?

Questions & Answers
1

Hi, I m totally new to unity.
I m trying to build AI in car game,
I am firing a ray from enemy car and checking whether there is a object or not.

Ray ray = new Ray(transform.position,transform.forward);
        RaycastHit hit;
		Debug.DrawRay(transform.position,transform.forward);
        if (Physics.Raycast(ray,out hit,rayDistance)) {
			if(hit.collider.tag == "rail") {
				Debug.Log("AI working");
				transform.Rotate(Vector3.up, 100*speed * Time.deltaTime);
			}
		}
		transform.Translate(0,0,speed);

This thing is working. but

Now i am not able to understand how to cast a ray at an angle of 45 degrees to car not world space so that when car take turn the ray still be at 45 degrees to the car.

2

Check out the Transform docs.

Specifically look at the functions:

TransformDirection,
TransformPoint,
InverseTransformDirection,
InverseTransformPoint.

Use these functions to convert from Local/World spaces to the other.

Something to consider : If Z is your forward axis, Vector3(1,0,1) would represent a 45 degree angle, forward/right.

Perhaps your could have a child object on the car perform a ray. As the child transform is relative to the parent it will have fixed position to the car.

I don’t want to post a load of code as, from personal experience, it is better to work thee functions out yourself to get to grips with how they work. Have a go, come back if you want further help :slight_smile:

Edit: You can probably use Vector3.Project to achieve your effect.