Resizing dynamically added BoxCollider to encapsulate all child objects' total bounds

Questions & Answers
1

I have a GameObject consisting of several children.
Each child holds another set of children that contain actual meshes, but the general shape of the total object can be summed up to a box (think, chest body and lid with meshes for wood and decor).

I haven’t been able to find a way to scale the boxcollider to represent the full size of the parent gameobject in world space. A lot of the answers I find solve similar issues with a Renderer component which seems deprecated.

What should I do here?
(this must be added and scaled dynamically)

2

Thanks to @RobAnthem who led me onto the right tracks. :slight_smile:
Here is the solution:

The parent sets up the children by calling something like

SetCollidersFrom<BoxCollider>(m_Body, m_Rotater.GetContainer());

which does

    public void SetCollidersFrom<CollType>(params GameObject[] from) where CollType : Collider
    {
        if (!m_UseCollider) { return; }
        if (from == null)   { Debug.LogWarning("<color=" + DebugColor + ">" + DebugName + "SetCollidersFrom -> Invalid parameters.</color>"); return; }

        int added = 0;
        List<MeshRenderer>  meshrend        = new List<MeshRenderer>();
        List<Bounds>        boundsForEach   = new List<Bounds>();
        Bounds              totalBounds     = new Bounds();
        int                 index           = 0;

        foreach (GameObject go in from)
        {
            if (!BlacklistedNames.Any(go.name.Contains))
            {
                var bounds = _GetChildRendererBounds(go);
                boundsForEach.Add(bounds);
                totalBounds.Encapsulate(bounds);
            }
        }

        foreach(GameObject go in from)
        {
            if (typeof(CollType) == typeof(BoxCollider))
            {
                BoxCollider bc = go.AddComponent<BoxCollider>();
                bc.enabled = true;
                bc.size = (boundsForEach[index].size * 2) * m_ColliderPadding;
                bc.center = new Vector3(0f, (bc.size.y / 2), 0f);
                added++;
                index++;
            }
        }

        if (added > 0)
        {
            Debug.Log("<color=" + DebugColor + ">" + DebugName + added.ToString() + " colliders set.</color>");
        }
    }

which uses helper function:

    private Bounds _GetChildRendererBounds(GameObject go)
    {
        var renderers = go.GetComponentsInChildren<Renderer>();

        if (renderers.Length > 0)
        {
            Bounds bounds = renderers[0].bounds;
            foreach (var rend in renderers)
            {
                if (!BlacklistedNames.Any(rend.gameObject.name.Contains))
                {
                    bounds.Encapsulate(rend.bounds);
                }
            }
            return bounds;
        }
        else { return new Bounds(); }
    }

And the result:
134637-colliders.png