Code to determine the distance between NPC and human's avatar

One of the code snippets I need to do is determine the distance between the NPC and the human avatar in order to determine if I should be running the animation code or not. There's already existing code by Christy Lock to do that for her AStar pathfinding class. This is a rebased version of it which should do the trick hopefully:

Vector3 diffAbsPos = FollowedSP.AbsolutePosition - m_botscenePresence.AbsolutePosition;
if (Math.Abs (diffAbsPos.X) < m_closeToPoint || Math.Abs (diffAbsPos.Y) < m_closeToPoint)
{
// run the attack code here which includes animation and reducing the health points of
// the attacked human, possibly pushing et cetera depending on the force applied
}

So what this does is get a vector between the scenepresence of the followed avatar (i.e. the human) and the scenepresence of the bot. Then it does some math which amounts to checking if either of the X or Y coordinates of the vector are less than the closetopoint (which is 1 i.e. one unit). Depending on the animation to be run, this could vary but 1 unit is good for now.