unity draw 3d arc between two objects

When I outset started game development with Unity3D, I used to stay away from some of the functions that I didn't understand. Unity Raycast is one such function. When I learnt most Raycasting, then I understood the importance and how Raycast tin make a lot of things easier. So, in this post nosotros will exist going through some basics of Raycast and and then likewise run across some lawmaking samples that y'all tin can use in your game.

Our objective is to brand sure you sympathize the line of code below by the terminate of the post.

          Physics.Raycast(transform.position, transform.TransformDirection(Vector3.forward), out hit, Mathf.Infinity, layerMask)        

What is Raycast in Unity?

Raycast every bit the name suggests is to cast a ray from 1 position to another. It's simply like a laser beam in the gaming globe. In Unity, Raycast uses mathematical variables like position, range etc. to make this possible. You can specify from where to where yous desire the ray to exist bandage or y'all tin can also cast a ray for an infinite distance in a detail direction. You tin can also ignore layers during ray casting. Raycast requires colliders in order to interact with the gameobjects. Any gameobject without colliders volition not trigger a hit. The object hit will be available in Raycasthit.

When is Raycast used?

Raycast can exist used for many purposes in gaming. Mostly information technology is used to find objects in a particular direction or for shooting. But, one thing to exist kept in heed while using Raycast is the outcome on operation. If y'all cast multiple rays of space length and so your game performance is going to endure. The general practice is to Raycast when some action happens. For example, in a shooting script Raycast is done simply when the mouse button is pressed.

An important matter to note is Raycasts will not detect colliders for which the Raycast origin is inside the collider.

Raycasting in Unity

You lot need to know about a few components before making a proper Raycast.

1. RaycastHit – this variable type is used to store the information received from the Raycast.
2. Layermask- this is used to mask one item layer you want the ray to interact or ignore.
3. Range – this specifies the range upwardly to which the casted ray volition travel. Information technology is always a better option to specify range as it helps in operation.

Raycasts from Photographic camera

Let's cast a basic ray from our camera in the forward direction. All yous need to exercise is to attach a script to the camera and add the below code to the script

          using UnityEngine public form ExampleClass : MonoBehaviour {          void FixedUpdate()     {          RaycastHit striking;         if (Physics.Raycast(transform.position, transform.TransformDirection(Vector3.forrard), out hit, 10))         {                          Debug.Log(hit.gameobject);         }         else         {                          Debug.Log("Did not Hit");         }     } }        

In the higher up script we are Raycasting to a range of x Units in the forrad direction. "Physics.Raycast" returns true if the ray hits a collider or else it volition render faux.

In the Raycast syntax the beginning input is the origin identify, second is the direction, tertiary is the output and fourth is the range. We can too add some other variable layermask to it. We will hash out it in the adjacent section.

Should you Raycast in Update or Fixed Update?

The reason I used fixed update is because Raycast is a physics holding and also it will help you to cease Raycasting when y'all pause your game in Unity3D with timescale.

Raycasting betwixt two points

You lot need to tweak the above lawmaking a little to cast a ray between two points. I am assuming you lot are attaching this script to point1.

          if (Physics.Raycast(transform.position, point2.transform.position-transform.position , out hitting, 10))         {                          Debug.Log("object is at ten units range");         }        

Alternatively, you can utilize the linecast part to bandage a line between two points. Linecast will render true if in that location are any objects with colliders between the ii points. You can apply the layermask to ignore some objects.

          if (Physics.Linecast(transform.position, point2.transform.position))         {             Debug.Log("colliders found between the two position");         }        

Raycasting from mouse bespeak

Mouse bespeak is a little fleck trickier than other things in Unity. The device screen is 2nd and the game earth is 3D. So, y'all need to catechumen the mouse point to game world position. You need to use the camera for this purpose. Go ahead and tag your camera as main camera before proceeding.

Converting mouse position to ray

          Ray ray = Camera.Main.ScreenPointToRay(Input.mousePosition);        

Cast a ray with the range and hit attribute

          if (Physics.Raycast(ray, out hit, 10)) {     Debug.Log(hit.gameobject); }                  

How to ignore a layer in Raycast?

It often comes to a situation where we don't want the ray to striking everything. For example, implementing friendly burn down in an FPS game. Y'all don't want your fire to hitting friends so, you can but add the friendly players to a layer and ignore them from Raycast. To ignore a layer from the Ray casted, you but need to add together the bit mask of the layer index to your Raycast expression. You need to add the variable shown beneath and modify the if statement from the higher up code. You can too get more than information on layermask from Unity3D transmission.

The layerMask variable needs to exist inverted inside the Update function.

          int layerMask = one << v;//scrap mask for layer number 5 layerMask=~layerMask //add the 2nd line if y'all desire to ignore layer five if not added information technology will Raycast merely to layer v            if (Physics.Raycast(transform.position, transform.TransformDirection(Vector3.frontwards), out hit, 10, layerMask))                  

Raycasthit

Raycasthit contains all details about the object hit by the Raycast. If the Raycast does non hitting whatsoever object then Raycasthit returns "Null". Yous can become the following details about the striking object.

1. Gameobject.
2. Collider attached to the object.
3. Distance of the object from the origin.
4. Transform
5. Rigidbody details

Is Raycasting performance expensive?

In Unity3D, Raycast is a very helpful part but needs to be used carefully. Many developers avoid Raycast in order to boost performance. Simply you demand not worry unless y'all are making a very performance hungry game. Just keep in mind a few things and you should be skillful.

1. Never forget to provide the range of Raycasts.
2. Try to avert multiple Raycasts simultaneously.
3. Utilize Raycast with a status similar push press inside Update.
4. Avert Raycasting against a mesh collider.
5. Utilise layer mask effectively.

Raycastall in Unity3D

If yous are looking for a list or assortment of objects hitting by a Raycast, and then Raycastall is your best choice.

                      RaycastHit[] hits;  hits = Physics.RaycastAll(transform.position, transform.forward, 50.0F);     foreach(Raycasthit i in hits)     {        Debug.Log(i.gameobject);     }        

Unity Raycast demo

Now that y'all sympathize how Raycast works in Unity3D. Let'due south try information technology out in a demo scene. Nosotros will create two cubes and ready them into two different layers. Nosotros volition try to hit the cube on the back. Here is the video of what nosotros are going to do.

We will skip the basics similar how to create a projection in Unity3D. I am assuming y'all already have a project to cast the ray.

Step1: Creating game objects

1. Go to bureaucracy window.
2. Select Create (+)>3D object>cube. Add two cubes.
3. We will be casting the ray from the photographic camera so, let's align the cube one behind the other from the cameras preceptive. You should be able to run into only one cube in the game window.

Step2: Calculation layers

1. Let's create two layers called enemy and friend.
2. Click layers dropdown on whatever gameobject's inspector view.
3. Select Add layer and enter the required details.
4. Assign the cube in front of camera as friend and the cube on the back every bit enemy.

Step3: Calculation the camera script

1. Create a new script component for the camera.
2. Add the script below. Remember the script name and the class name should be the same.
3. Relieve and play. We are Raycasting to a altitude of ten Units. So, the enemy must be destroyed only at 10 Unit distance.

          using UnityEngine; public form for_raycasting : MonoBehaviour {          void FixedUpdate()     {         int layerMask = 1 << 6;         layerMask = ~layerMask;          RaycastHit hit;         if (Physics.Raycast(transform.position, transform.TransformDirection(Vector3.forward), out striking, x,layerMask))         {                          Destroy(hit.collider.gameObject);         }         else         {                          Debug.Log("Did non Hitting");         }     } }        

Brand Raycast visible in the editor

Y'all tin utilise Debug.DrawRay(origin,management,color) to depict a ray in the Unity editor. But to make it similar to the ray nosotros have cast you lot demand to use the same ray.

Normally to cast a ray, y'all don't need to create a ray variable. You can put the raycast expression in an if statement and it will render true if it hits something. To draw the ray, we will create a ray variable that takes the origin and management as input. Then we draw a ray with these properties.

          using UnityEngine; public class Raycasting : MonoBehaviour {          RaycastHit hit;     void FixedUpdate()     {         Ray ray=new Ray(transform.position, transform.TransformDirection(Vector3.forrard));                  if (Physics.Raycast(ray, out hit, x))         {                          Debug.Log(hit.collider);         }         else         {             Debug.DrawRay(ray.origin, ray.direction*10f,Color.red);                          Debug.Log("Did non Hit");         }     } }        

Length of Debug.DrawRay

Unity3D docs is a trivial silent in this area. It doesn't conspicuously land how to command the length of the ray in Debug.DrawRay. Length of the ray depends on the magnitude of the management vector. In the above example, nosotros have used a unit vector and multiplied it with the required length. You cannot multiply it with Mathf.Infinity to get in infinite in length. it doesn't work. You tin can only raycast with infinite length merely cannot depict a ray. You tin can use a big number like 100000f to solve the problem.

          Debug.DrawRay(ray.origin, ray.direction*10000f,Color.red);        

Make Ray visible in game

The above section was near making the ray visible in Unity editor but if you build the game the ray won't be visible in the game. If you want the ray to be visible in your game then you need to use the line renderer. You tin can set the start and end point every bit shown in the script beneath.

          using UnityEngine; public form Raycasting : MonoBehaviour {     LineRenderer lin;          RaycastHit hit;     void Kickoff()     {         lin=GetComponent<LineRenderer>();     }     void FixedUpdate()     {         Ray ray=new  Ray(transform.position,transform.TransformDirection(Vector3.forward));                  if (Physics.Raycast(ray, out hit, 10))         {                          Debug.Log(hit.collider);         }         else         {             lin.SetPosition(0,ray.origin);             lin.SetPosition(ane,ray.management*10f);                          Debug.Log("Did not Hit");         }     }        

Raycast2D in Unity3D

Raycasts can be used in second games too only a normal Raycast will not collide with second colliders. You need to use Raycast2D for this purpose.

You just need to supervene upon all the 3D components in the code with second.

                      using UnityEngine public class ExampleClass : MonoBehaviour {          void FixedUpdate()     {          RaycastHit2D hit;         if (Physics2D.Raycast2D(transform.position, transform.TransformDirection(Vector2.forrad), out hit, 10))         {                          Debug.Log(hit.gameobject);         }         else         {                          Debug.Log("Did not Hit");         }     } }                  

Promise the post covered all the required aspects of Raycast. If you take any questions, you lot can leave them in the annotate section below.

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Source: https://vionixstudio.com/2020/12/28/unity-raycast/

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