(No anwers? :( )How to spawn Random Pedestrians in a raduis?

Questions & Answers
1

Hello Everybody,

im working on a Open-World game with a big, big ,big Open World.
I have some Pedestrians with my AI (Nav Mesh, Active Ragdoll based )
and i want that they spawn in an area 100 meters before the player, and 100 meters after the player they de-spawn. Like A circle- but they only should spawn were place is, not inside a tree or a car :D.
Also i could use a pool for the Humans. How would i do the spawning and the pool?

thanks in advance!!!

Regards, T

3

Hi,

This question can be broken up into different steps. All within a modified for loop:

for (int i = 0; i < NumberOfSpawns; i = i) { /* Code Below Goes In Here*/ }

Note that we are not doing i++. Because we want to manually increase the count if we had a successful spawn.

Within the for loop we need a few steps:

Step 1: The first is to find a random spawning position.

This can be done with the Random.Range() function mentioned above. Use the following Code:

// Get position of Circle
    float circleParam = 2 * Mathf.PI * Random.Range (0.0f, 1.0f );
    // Select Start Position
    Vector3 startPos = new Vector3 (
                     radius * Mathf.Sin (circleParam),
                     0.5f, /* Spawn above ground */
                     radius * Mathf.Cos (circleParam )
     );

Step 2: Check for Collision

In this step use SpherecastAll to check for collision. below is a written function that checks for collision within a certain radius.

// Inside for loop:
bool canSpawn = !isCollision (prefabRadius, startPos);


// The function
bool isCollision (radius, position) {
      // Create new ray
      Ray ray = new Ray(position, Vector3.up);

     // Create Raycast hits array
      RaycastHit[] hits;
       
      // Do the raycast
      hits = Physics.SphereCastAll(ray, radius, 0f); //Can change 0f to prefabHeight / 2.1f if you need to check height

return hits.length > 0;
}

Step 3: Spawn or continue to next step

No that we know if it will collide with an object or not we can write the end of the for loop here:

if (canSpawn) { // you can spawn it so do it
    // Instantiate the object
   GameObject obj = Instantiate (prefab, startPosition, Quaternion.identity * Quaternion.Euler (new Vector3(0, Range.Random(0, 359), 0))) as GameObject;

  // IMPORTANT: Increase the loop counter or you will get stuck in the loop
i++;
} else 
    continue; // Step to the next iteration without increasing i

All of this will ensure that you spawn the selected amount of objects and that they do not collide.

FINALLY: If you want them to despawn when out of range then keep track off all the objects in a list and use this function below in the LateUpdate function:

void LateUpdate () {
   for (int i = 0; i < enemyList.Count; i = i) {
  // Get the distance between them
   float distanceFromPlayer = Vector3.Distance (playerPosition, enemyList*.transform.position);*

// Remove if greater than radius
if (distanceFromPlayer > radius) {
// remove from list
enemyList.Remove (enemyList*);*
} else {
// No Object Removed so increase i
i++;
}
}
}

2

Check out Instantiate and Random.Range from documentary