detect if object is near

General Discussion
3

I guess one lightweight way to do that is to compare the squared distance.

radius = 2.0
radiusSq = radius * radius
isNear = (obj.getPos() - target.getPos()).lengthSquared() <= radiusSq

Or even, if you do not want to take the Z into account:

radius = 2.0
radiusSq = radius * radius
isNear = (obj.getXy() - target.getXy()).lengthSquared() <= radiusSq