A method and system for measuring and reacting to human interaction with elements in a space, such as public places (retail stores, showrooms, etc.) is disclosed which may determine information about an interaction of a three dimensional object of interest within a three dimensional zone of interest with a point cloud 3D scanner having an image frame generator generating a point cloud 3D scanner frame comprising an array of depth coordinates for respective two dimensional coordinates of at least part of a surface of the object of interest, within the three dimensional zone of interest, comprising a three dimensional coverage zone encompassing a three dimensional engagement zone and a computing comparing respective frames to determine the time and location of a collision between the object of interest and a surface of at least one of the three dimensional coverage zone or the three dimensional engagement zone encompassed by the dimensional coverage zone.