Can't get trees to spawn above sea level using Terrain and Prefabs

Unity Engine
1

I really don’t know what’s wrong, the logic checks out, maybe I’m just missing something simple. seaLevel returns 99 and Terrain height is 100.

This code below is responsible for spawning the trees, if I have the conditional coding read “if(hit.point.y >= seaLevel)” then all the trees will spawn except for trees on hills and mountains, if I switch the operand to <= it doesn’t spawn any trees at all.

Thanks for any help!

 void Start()
    {
        seaLevel = terr.transform.position.y - amountInGround;
        Debug.Log("Sea Level: " + seaLevel);
        Debug.Log("Terrain Height: " + terr.transform.position.y);

        if (treePrefabs.Length != 0)
        {
            for (int i = 0; i < startingTrees; i++)
            {
                Vector3 Loc = GenerateRandomLocation();
                int z = Random.Range(0, treePrefabs.Length);
                RaycastHit hit;
                Ray ray = new Ray(Loc + Vector3.up * 100, Vector3.down);
                if (Physics.Raycast(ray, out hit, Mathf.Infinity, mask))
                {
                    if(hit.point.y >= seaLevel) //checks to see if object is above sea level, seaLevel is 99
                    {
                        // this is where the gameobject is actually put on the ground
                        Vector3 Loc1 = new Vector3(Loc.x, hit.point.y - amountInGround, Loc.z);
                        Instantiate(treePrefabs[z], Loc1, transform.rotation);
                    }
                }
            }

        }
   }

   Vector3 GenerateRandomLocation()
    {
        float xPos = Random.Range(-spawnBounds + 10, spawnBounds - 10);
        float zPos = Random.Range(-spawnBounds + 10, spawnBounds - 10);
        return new Vector3(xPos, 1f, zPos);
    }
2

You must find a way to get the information you need in order to reason about what the problem is.

What is often happening in these cases is one of the following:

  • the code you think is executing is not actually executing at all
  • the code is executing far EARLIER or LATER than you think
  • the code is executing far LESS OFTEN than you think
  • the code is executing far MORE OFTEN than you think
  • the code is executing on another GameObject than you think it is

To help gain more insight into your problem, I recommend liberally sprinkling Debug.Log() statements through your code to display information in realtime.

Doing this should help you answer these types of questions:

  • is this code even running? which parts are running? how often does it run? what order does it run in?
  • what are the values of the variables involved? Are they initialized? Are the values reasonable?
  • are you meeting ALL the requirements to receive callbacks such as triggers / colliders (review the documentation)

Knowing this information will help you reason about the behavior you are seeing.

You can also put in Debug.Break() to pause the Editor when certain interesting pieces of code run, and then study the scene

You could also just display various important quantities in UI Text elements to watch them change as you play the game.

If you are running a mobile device you can also view the console output. Google for how on your particular mobile target.

Another useful approach is to temporarily strip out everything besides what is necessary to prove your issue. This can simplify and isolate compounding effects of other items in your scene or prefab.

Here’s an example of putting in a laser-focused Debug.Log() and how that can save you a TON of time wallowing around speculating what might be going wrong:

3

Thanks for the time and the late reply! I wasn’t aware about debug.break, recently got into unity and still learning a lot of things, I figured it out shortly after I posted here but couldnt find a way to delete the post. Glad I didn’t though, you provided me with good advice!

4

This is by design. Ideally instead of telling us you “figured it out” it would be AWESOME if you added something useful to this thread for the next guy, like maybe … the solution in your case. You weren’t the first guy to have this issue and you’re never gonna be the last guy. Pay it forward.