Camera.ScreenToWorldPoint

Description

Transforms position from screen space into world space.

Screenspace is defined in pixels. The bottom-left of the screen is (0,0); the right-top is (pixelWidth,pixelHeight). The z position is in world units from the camera.

#pragma strict
// Draw a yellow sphere in the scene view at the position
// on the near plane of the selected camera that is
// 100 pixels from lower-left.
function OnDrawGizmosSelected() {
	var camera: Camera = GetComponent.<Camera>();
	var p: Vector3 = camera.ScreenToWorldPoint(new Vector3(100, 100, camera.nearClipPlane));
	Gizmos.color = Color.yellow;
	Gizmos.DrawSphere(p, 0.1F);
}

	// Draw a yellow sphere in the scene view at the position
	// on the near plane of the selected camera that is
	// 100 pixels from lower-left.
	using UnityEngine;
using System.Collections;

public class ExampleClass : MonoBehaviour {    
    void OnDrawGizmosSelected() {
		Camera camera = GetComponent<Camera>();
        Vector3 p = camera.ScreenToWorldPoint(new Vector3(100, 100, camera.nearClipPlane));
        Gizmos.color = Color.yellow;
        Gizmos.DrawSphere(p, 0.1F);
    }
}