Vector3 midPoint = new Vector3();
midPoint.x = (point1.x + point2.x) / 2;
midPoint.y = (point1.y + point2.y) / 2;
midPoint.z = (point1.z + point2.z) / 2;
midPoint = midPoint.floor();
// Center the two coords to origin.
point1.subtract(midPoint);
point2.subtract(midPoint);