'Get closest point between GameObject (inside the cube collider) and 3D cube collider

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How do I calculate the distance of a game object (inside a cube collider) from the cube collider surface? The existing calculations were made from the cube surface outwards so I got 0 when I used the collider.closestpoint or collider.closestpointonbounds.

unity3dcollider


Solution 1:[1]

The simplest (but computationally not the cheapest) would be to not rely on your current collider for the distance, but to add a set of small colliders around the edge of the object (so 6 colliders, one per face of the cube). Using Collider.ClosestPoint() on all 6 faces and calculating the distance like that would give you the results you need.

Solution 2:[2]

First convert a point to local space.

var localPoint = transform.InverseTransformPoint(worldPoint);
var extents = collider.size * 0.5f;
var closestPoint = localPoint;

Compute the distance to each face.

var disx = extents.x - Mathf.Abs(localPoint.x);
var disy = extents.y - Mathf.Abs(localPoint.y);
var disz = extents.z - Mathf.Abs(localPoint.z);

Find the closest face (smallest distance) and move the closest point along this axis.

if(disx < disy)
{
    if (disx < disz)
        closestPoint.x = extents.x * Mathf.Sign(localPoint.x); //disx
    else
        closestPoint.z = extents.z * Mathf.Sign(localPoint.z); //disz
}
else
{
    //......
}

Plus the offset of the collider, convert to world space.

closestPoint += collider.center;
transform.TransformPoint(closestPoint);

Solution 3:[3]

You can Calculate by Vector3.Distance

some example

 float minDistance =2;
 float Distance = Vector3.Distance(other.position, transform.position);
 if(Distance < minDistance)
 {
     //some code stuffs
 }
 else if(Distance > minDistance){
     //some code stuffs
 }

Useful information about Vector3.Distance and getting Distance from object source: https://docs.unity3d.com/ScriptReference/30_search.html?q=Distance

Sources

This article follows the attribution requirements of Stack Overflow and is licensed under CC BY-SA 3.0.

Source: Stack Overflow

Solution Source
Solution 1 Alex Leest
Solution 2
Solution 3 BayEggex

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