1

I’m trying to get NPCs to consistently spawn in front of the PC, and to this end I’m trying to randomly select a point in an arc in front of the PC. To that end, I’ve been doing this:

Vector3 RandomPointInCircle(Vector3 center, float radius, float angle){	//Draws circle of radius, with center center, and locates a point on that circle within angle angle 	
		Vector3 position;
		position.x = center.x + radius * Mathf.Sin (angle * Mathf.Deg2Rad);
		position.y = center.y + radius * Mathf.Cos (angle * Mathf.Deg2Rad);
		position .z = center.z;
		return position; 
	}

I thought that passing it the player’s position, a radius of 5, and an angle of Random.range(45, -45) would result in enemies spawning at random points within a 90 degree arc in front of the player, but every enemy spawns at the same point, to the player’s right- is my math slightly borked?

2

Your code should work just fine, however keep in mind that when in 3D the y-axis is up. So since your arc is on the x-y plane, the point will be displaced on the x axis and the y-axis. If you want a point on the x-z-plane you should use z and not y in your code.

Also keep in mind that you work in worldspace and not relative to a certain object. (just saying since you said “in front of the player”)

edit

To specify a point in localspave you either have to write your method a bit more general and then use the Transform’s TransformPoint method, or directly use the transforms local axis in the calculation:

Vector3 RandomPointInCircle(float radius, float angle){
    float rad = angle * Mathf.Deg2Rad;
    Vector3 position = new Vector3(Mathf.Sin( rad ), 0, Mathf.Cos( rad ));
    return position * radius;
}

// Now use like this:
var localPoint = RandomPointInCircle(5,angle);
var worldPoint = transform.TransformPoint(localPoint);

The other way would be to pass a Transform reference to the method and use it like this:

Vector3 RandomPointInCircle(Transform trans, float radius, float angle){
    float rad = angle * Mathf.Deg2Rad;
    Vector3 position = trans.right * Mathf.Sin( rad ) + trans.forward * Mathf.Cos( rad );
    return trans.position + position * radius;
}