OnTrigger Events Work With Delay - unity3d

Question

I've got a bullet script with a particle system and a decal.
I think that it has something to do with these events not being able to fire in time or with fps in update. Not sure yet.
So, it's being late.
The ellow points are where the particles start to play. They should be right on these wooden walls. There should be three particles working and three bullet holes, kinda bullet penetrating one wall and getting destroyed on the second one.
THE QUESTION IS HOW TO MAKE IT WORK NORMAL, SO THAT THE TRIGGERS WORK WHEN NEEDED AS WELL AS THE PARTICLES AND THE DECALS? Maybe there's a way to excellerate the code to work on time? Or maybe there's another problem with that?
The screenshot:
The Code:
public class BulletScript : MonoBehaviour {
public bool isThrough = true;
public float BulletSpeed = 100;
public float CurrentDamage;
public float EnterLuft = -0.005f;
public float ExitLuft = 0.05f;
public GameObject woodParticle;
private ContactPoint CollisionPoint;
public GameObject BulletMarkPref;
Rigidbody bullet;
private void Start()
{
bullet = this.GetComponent<Rigidbody>();
}
void FixedUpdate () {
bullet.velocity = Vector3.forward * BulletSpeed;
//this.transform.Translate(Vector3.forward * BulletSpeed * Time.deltaTime);
}
private void OnTriggerEnter(Collider other)
{
Transform hitPoint = this.transform;
LevelObject.LvlObjectType objectType = other.gameObject.GetComponent<LevelObject>().objType;
if(objectType == LevelObject.LvlObjectType.obstacle)
{
if (isThrough)
{
Instantiate(woodParticle, hitPoint.localPosition, Quaternion.LookRotation(-hitPoint.forward)).GetComponent<ParticleSystem>().Play();
LeaveBulletMark(this.transform, true);
}
else
{
Instantiate(woodParticle, hitPoint.localPosition, Quaternion.LookRotation(-hitPoint.forward)).GetComponent<ParticleSystem>().Play();
LeaveBulletMark(hitPoint, true);
Destroy(this.gameObject);
}
}
else if(objectType == LevelObject.LvlObjectType.obstacle)
{
Destroy(this.gameObject);
}
else if(objectType == LevelObject.LvlObjectType.wall)
{
LeaveBulletMark(hitPoint, true);
Destroy(this.gameObject);
}
}
private void OnTriggerExit(Collider other)
{
Transform hitPoint = this.transform;
Instantiate(woodParticle, hitPoint.localPosition, hitPoint.rotation).GetComponent<ParticleSystem>().Play();
LeaveBulletMark(hitPoint, false);
}
void LeaveBulletMark(Transform hitPoint, bool ifEnter)
{
GameObject TemporaryBulletMarkHandler;
TemporaryBulletMarkHandler = Instantiate(BulletMarkPref, hitPoint.localPosition, Quaternion.LookRotation(ifEnter ? hitPoint.forward : CollisionPoint.normal)) as GameObject;
isThrough = false;
TemporaryBulletMarkHandler.transform.Translate(hitPoint.forward * (ifEnter ? 0.005f : -0.005f));
}
}

Answer 1

I don't think your problem is something simple with the code. There is an inherent issue with calculating fast moving objects like bullets with true physics calculations especially if they are small. Often between physics updates, they pass through wall colliders completely without registering.
You have to think of it like this to see the problem. The bullet isn't tracked continuously along its trajectory. It has a starting location, a formula for its movement and it calculates a new location at each physics update. You could fire a bullet straight at a wall, and in one update the bullet would be several meters in front of the wall, and in the next, it would be several meters behind the wall without ever triggering a collision. This is why so many game use ray tracing to calculate bullet trajectories. The bullet movement isn't perfectly accurate, especially for long shots, but obstructions to the bullet path are registered.
By default unity's Physics Engine runs at 50 frames per second. A modern bullet travels between 1200 and 1700 m/s. That gives you a distance between 24 and 34 meters traveled between frames. Even a small object falling at terminal velocity (54 m/s) might pass through a collider unnoticed. If you made a 1-meter thick box collider, you would likely register a falling object but not a bullet.
I think you could do some clever combination of ray tracing and bullet physics to get the best of both worlds. Maybe you could ray trace from the bullet at each fixed update or there may be some better technique already invented for this exact situation that I don't know about.