Question by Caruzo · May 05, 2019 at 08:16 PM · rigidbody velocity addforce

Inconsistent AddForce results

Hey there,

I am trying to implement a pushback effect as seen here: https://youtu.be/v2uOGQegj2c?t=270

When a projectile hits a player, the player is pushed back in a direction relative to the hit collision position.

I have tried this snippet of code:

 private void OnCollisionEnter(Collision other)
         {
             if (other.gameObject.name.Contains("Fireball"))
             {
                 Debug.Log("Fireball collided with player");
     
                 directionRaw = transform.position - other.transform.position;
                 directionRaw.Normalize();
     //rb is the rigidbody of the player
                 rb.AddForce(directionRaw * force * Time.fixedDeltaTime, ForceMode.Impulse);
     
             }
         }

Also, I have tried this example:

 private void OnCollisionEnter(Collision other)
     {
         if (other.gameObject.name.Contains("Fireball"))
         {
             Debug.Log("Fireball collided with player");
 
             directionRaw = transform.position - other.transform.position;
             direction.Normalize();
             rb.velocity = Vector3.Lerp(rb.velocity, directionRaw, force);
 
         }

However, none of them seem to work as intended - either not pushing back the player at all or just by a small distance, barely noticeable. I tried to set the force to a great number but the results are the same - not working.

Another thing I tried is to set the AddForce or Velocity change in a FixedUpdate like so:

 private void FixedUpdate()
     {
         if (hit && pushbackTime > 0)
         {
 //The example with velocity change
             rb.velocity = Vector3.Lerp(rb.velocity, directionRaw, force * Time.fixedDeltaTime);
 
 //The example with AddForce
             rb.AddForce(directionRaw * force * Time.fixedDeltaTime, ForceMode.Impulse);
         }
         else if (pushbackTime == 0)
         {
             hit = false;
         }
     }
 
 private void OnCollisionEnter(Collision other)
     {
         if (other.gameObject.name.Contains("Fireball"))
         {
             Debug.Log("Fireball collided with player");
             directionRaw = transform.position - other.transform.position;
             directionRaw.Normalize();
             pushbackTime = 0.5f;
             hit = true;
         }
     }

Please keep in mind that the incrementing of pushbackTime is set in another function, which is working perfectly fine - thus not necessary to include it in here.

The last option I listed gives me very inconsistent pushbacks. As the game is 3D, I always set the Y axis of the directionRaw to be around 30-45 as I want the player to be pushed back and sort of imitate a jump back.

All in all, none of the techniques are working or working adequately.

Any help with the pushback effect will be much appreciated.

Add comment