[Solved] Detecting objects with OverlapSphere within the frame they are created?

Question

Hey,

I’ve been trying to procedurally generate several "road segments“ with obstacles at random positions on top of the segments. This has to be done when the scene loads. So my approach was, to solve this with a while-loop inside the Start() method and check for overlaps with Physics.OverlapSphere. I ran into the problem, that Physics.OverlapSphere returns either no object at all or every object on a specific segment when setting the radius very high. After several different attempts in solving this issue, I thought that maybe this has to do with the fact, that everything happens within one singular frame. I already found this post to a similar problem: https://answers.unity.com/questions/587465/collision-detection-within-1-frame.html

Does this also apply to Physics.OverlapSphere? If so, are there ways to solve this differently?

I hope, someone can help me with this!

Thanks

My Code: (Simplified, because the functionality is split across several scripts)

    void Start()
    {
     while (attempts < maxObjects) 
      {
       PlaceObstacleOnRoad(obstacle, segment);
       attempts++;
       }
    }
    void PlaceObstacleOnRoad(GameObject obstacle, GameObject segment)
         {
             Collider segmentcol = segment.GetComponent<Collider>();
             Collider obstaclecol = obstacle.GetComponent<Collider>();
         
             //Get Range of Possible Positions on Segment
         
             float placementZMax =  0.5f - (obstaclecol.bounds.extents.z / segment.transform.localScale.z); 
            //Local Position Max

            float placementZMin = -0.5f + (obstaclecol.bounds.extents.z / segment.transform.localScale.z); 
            //Local Position Min
         
             float placementZPosition = Random.Range(placementZMin, placementZMax);
             Vector3 placementPosition = new Vector3(obstaclecol.bounds.size.x, 0f, placementZPosition);
         
             Collider[] overlaps;
         
       overlaps = Physics.OverlapSphere(segment.transform.TransformPoint(placementPosition), radius);
                     
             if (overlaps.Length < 1)
                 { 
                    //Spawn Code Here
                 }
 }

[1]: https://answers.unity.com/questions/587465/collision-detection-within-1-frame.html

Answer 1

Best Answer

Answer by mfvlk · Mar 22, 2020 at 04:54 PM

I solved it by turning the function wrapping the while-loop into a coroutine and using WaitForFixedUpdate().

Add comment · Show 4 · Share

Don_Raphael · Apr 30, 2020 at 11:38 AM 0

Share

I think I may be having a similar problem is there any chance you can expand on your own answer? Not sure how you would structure the coroutine (where you call the WaitForFixedUpdate() or where you call the coroutine generally?)w

Thanks!

mfvlk Don_Raphael · Apr 30, 2020 at 12:14 PM 0

Share

Yes, sure! Basicly you'd just have to call WaitForFixedUpdate() inside the while-loop, you use to spawn the "obstacles" with. I have put it at the end, right after I spawned the new instance, so that I could be sure, if the while-loop is executed again, all the colliders are already updated by unity, if that makes sense. Would look like this:

  do
             {
                
                //Check if obstacle can be spawned
     
                  //Spawn it
     
                 //Wait for FixedUpdate to update Colliders
                 yield return new WaitForFixedUpdate();
     
             } while (rounds < maxRounds);

$$anonymous$$y coroutine only consists of that (do-)while-loop. So you can call it anywhere you would want that loop to happen. Hope that helps :)

Don_Raphael mfvlk · Apr 30, 2020 at 01:00 PM 1

Share

Literally just came back to say that I worked it out! Thanks so much this had sent me into a rage yesterday feel like an absolute muppet now hah!

Show more comments

[Solved] Detecting objects with OverlapSphere within the frame they are created?

1 Reply

Your answer

Follow this Question

Related Questions