Cone Shaped Bullet Spread.

So I am working on a weapon system. And I saw some threads about Cone Bullet Spread. But It's not working for me.
Code:

Code (CSharp):

1.  
2.             var bullet = (GameObject)Instantiate(
3.                 bulletPrefab,
4.                 bulletSpawn.position,
5.                 bulletSpawn.rotation);
6.  
7.  
8.  
9.             bullet.GetComponent<Rigidbody>().AddForce(bullet.transform.forward * shootForce);
10.  
11.             NetworkServer.Spawn(bullet);
12.  
13.  

How can I add bullet spread in the shape of a cone that I can modify the amount depending on such like If the player is running or not.

Thanks in advance

 

If it doesn't have to be a circular cone, you can use the following to make a frustum instead, and adjust the coneSize variable according to your speed to get the decided effect.

Code (CSharp):

1.  
2.     public float coneSize;
3.  
4. ...
5.           var bullet = Instantiate(bulletPrefab);
6.  
7.             float width = Random.Range(-1f,1f) * coneSize;
8.             float height = Random.Range(-1f,1f) * coneSize;
9.  
10.             bullet.GetComponent<Rigidbody>().AddForce(transform.forward * shootForce + transform.right * width + transform.up * height);
11.      
12.  

Test project : https://drive.google.com/file/d/0B4yTMINoNEheRlZiQ1Y2ZjFsaGM/view?usp=sharing

Hope this was helpful

 

A much more efficient approach would be to apply spread to the rotation when you instantiate the bullet and then apply forward force.

I believe this should work..

Code (CSharp):

1. public float ConeSize;
2.  
3. float xSpread = Random.Range(-1, 1);
4. float ySpread = Random.Range(-1, 1);
5. //normalize the spread vector to keep it conical
6. Vector3 spread = new Vector3(xSpread, ySpread, 0.0f).normalized * ConeSize;
7. Quaternion rotation = Quaternion.Euler(spread) * bulletSpawn.rotation;
8. var bullet = (GameObject)Instantiate(bulletPrefab, bulletSpawn.position, rotation);

 

I would prefer a circular cone.

Will give it a shot

 

Neither of those worked. Is there a way to do this with raycasts?

 

there are 2 classic approaches to bullets and they will determine how you do "spread". the two ways are raycast with animations and sprites and the other is to physically spawn a bullet into the world.

If you are using raycast bullets the best way is to use a ray object in the script. http://docs.unity3d.com/ScriptReference/Ray.html you can alter the direction of the ray with Random.Range on the vertical and horizontal axis. This will simulate a random spread that is not predictable.

If you are instantiating the bullet into the world and using the bullet's collision to determine hits all you need to do is spawn the bullet at the point matching the rotation. Then alter the rotation the same way.

Many big game companies are going over to the spawned bullets because it gives the ability for bullet drop, wind deviation, and flight time where as raycasts are like shooting lasers. They are unaffected by physics other than line of sight.

 

Is it possible / fairly easy to simulate the physics for a physical bullet?

 

yes. all you do is make an actual bullet. the rigidbody will make the bullet effected by gravity for "bullet drop". If you want wind you need to script the wind physics by adding the winds directional force ever fixed update. then when you fire you place a bullet at the muzzle of the gun and give it an impulse force. BLAM the built in physics will take care of the rest. Another trick if you are going to use physical bullets is to make a bullet pool to use from so you are not instantiating and destroying during runtime.

 

I ment for a raycast sorry. I know how to add physics to a physical bullet. But is it easy to simulate on a raycast? things like traveltime etc.

 

there is always https://docs.unity3d.com/ScriptReference/Random-insideUnitSphere.html ; spread being controlled by the size of the sphere and the "distance" that sphere is reckoned to be from the muzzle (i.e. 1m spread at 100m)

doesn't matter what approach you take with simulating the projectile you still need to work out the rotation, raycast or force, both need to know what direction they're going in.

 

How would I do that? This is what I currently use:

Code (CSharp):

1.   if (Physics.Raycast(camTransform.TransformPoint(0,0,0.1f), camTransform.forward, out hit, range))
2. {
3. //my code
4. }
5.  
6.  

Thats pretty much everything I use atm.

 

I'd recommend using an empty for the muzzlepoint rather than the offset, makes things simpler


second arguement in the raycast would be something like:

Code (csharp):

1.  
2. (muzzle.transform.position - ((d * tranform.forward) + Random.insideUnitSphere(r))).normalize
3.  

(i.e. the red line as a unit direction)

use "insideUnitSphere if you want to have a higher density of shots in the middle, onUnitSphere for a more even spread

 

How would I apply your code to my code? To me this seems very confusing.

 

What do you mean neither worked? They work perfectly fine when I test them. Please elaborate.

 

Sorry. My bad. I was a bit quick at typing then. I ment that I need one that will work for Raycasts as I have figured out that's the route I want to take.

Sorry for the confusion.

 

Is there a reason you're using raycasts for this instead of just a projectile? An actual physics based projectile would be much more efficient and you could encapsulate the collision handling inside a Bullet script.

 

I have experimented and I just decided that a raycast is the route I want to take. No real

 

Well, you can still use the method I posted above to calculate a rotation. I believe if you normalize the euler angles of the resulting rotation it should give you a functioning conical direction vector. I don't have time to test it though. If you test it please let me know if it works

Example:

Code (CSharp):

1. public void ConicalBulletRaycast(Transform bulletSpawn, float coneSize, float range)
2. {
3.      float xSpread = Random.Range(-1, 1);
4.      float ySpread = Random.Range(-1, 1);
5.      //normalize the spread vector to keep it conical
6.      Vector3 spread = new Vector3(xSpread, ySpread, 0.0f).normalized * coneSize;
7.      Vector3 direction = ((Quaternion.Euler(spread) * bulletSpawn.rotation).eulerAngles).normalized;
8.      RaycastHit hit;
9.      if (Physics.Raycast(bulletSpawn.position, direction, out hit, range))
10.      {
11.        //handle collision
12.      }
13. }

 

as a general answer, very high velocity objects can cause the physics engine issues (missed collisions, passing through objects etc.) raycasts can be a lot more reliable in those instances.

... instead of the "camTransform.forward". r and d would be variables

r=1 d=100

 

They added continuous and continuous dynamic collision detection modes to prevent that.

 

Oh?

How does that work. Cause what LeftyRighty said is currently why I don't use Prefabs.

 

I'm not sure exactly how it's handled internally but I assume it uses raycasts to determine if a collision occurs between physics updates. It should work exactly like implementing your own raycast methods for collisions. You can read more about the Detection Modes here.