How can I destroy trees when placing a building in an RTS?

Question

I am developing RTS game. When I build buildings on the Terrain, any trees that were in that location end up intersecting with the building.

I want to remove all trees from the building's footprint when placing.

Can I use the building's OnTriggerStay to detect tree colliders with a particular tag and destroy the trees? Or is there a better way to clear out these trees?

Answer 1

Here is my solution:

void Update()
{

    TerrainData terrain = Terrain.activeTerrain.terrainData;
    ArrayList instances = new ArrayList();

    foreach (TreeInstance tree in terrain.treeInstances)
    {
        distanceG = Vector3.Distance(gameObject.transform.position, tree.position);

        distance = Vector3.Distance(Vector3.Scale(tree.position, terrain.size) + Terrain.activeTerrain.transform.position, transform.position);

        if (distance < closeRange)
        {
            // the tree is in range - destroy it
            print("1");
        }
        else
        {
            // tree is out of range - keep it
            instances.Add(tree);

        }
    }
    terrain.treeInstances = (TreeInstance[])instances.ToArray(typeof(TreeInstance));

}

Answer 2

When you place the building you could search for any tree object in a certain radius around it and if it's less than a certain distance delete them. That way you wouldn't need collision.

You would need a reference to the trees in the scene to access their position information.

Answer 3

Assuming your buildings have a rectangular base, you can use Physics.OverlapBox / Physics2D.OverlapBox to get all the colliders which overlap the area where you want to put down the building and decide what to do with them depending on object type.