Physics.Raycast 射线投射

public static bool Raycast(Vector3 origin, Vector3 direction, float maxDistance = Mathf.Infinity, int layerMask = DefaultRaycastLayers, QueryTriggerInteraction queryTriggerInteraction = QueryTriggerInteraction.UseGlobal);

    using System.Collections;
    public class ExampleClass : MonoBehaviour {
        void Update() {
            RaycastHit hit;
            if (Physics.Raycast(transform.position, -Vector3.up, out hit))
                float distanceToGround = hit.distance;
        }

    using UnityEngine;
    public class ExampleClass : MonoBehaviour {
        void Update() {
            Ray ray = Camera.main.ScreenPointToRay(Input.mousePosition);
            if (Physics.Raycast(ray, 100))
                print("Hit something");
        }
    }

Physics.CapsuleCast 胶囊投射

public static bool CapsuleCast(Vector3 point1, Vector3 point2, float radius, Vector3 direction, out RaycastHit hitInfo, float maxDistance = Mathf.Infinity, int layerMask = DefaultRaycastLayers, QueryTriggerInteraction queryTriggerInteraction = QueryTriggerInteraction.UseGlobal);

胶囊是由radius半径与point1和point2位置的两个球形成胶囊的两端定义。返回胶囊沿direction方向碰到的第一个碰撞器。这通常用于投射不需足够的精度，因为你要找出一个特定大小的物体，如人物，能移动到某处而不在途中碰撞到任何东西。

    using UnityEngine;
    using System.Collections;
    public class ExampleClass : MonoBehaviour {
        void Update() {
            RaycastHit hit;
            CharacterController charContr = GetComponent<CharacterController>();
            Vector3 p1 = transform.position + charContr.center + Vector3.up * -charContr.height * 0.5F;
            Vector3 p2 = p1 + Vector3.up * charContr.height;
            float distanceToObstacle = 0;
            // Cast character controller shape 10 meters forward to see if it is about to hit anything.
            if (Physics.CapsuleCast(p1, p2, charContr.radius, transform.forward, out hit, 10))
                distanceToObstacle = hit.distance;
    }