The viewpoint's line of sight is along the line drawn from the camera position to the target point. In other words, the top edge of the VRML browser will be perpendicular to the upVector . The default value of the upVector is the Y-axis. Thus the default behavior of a Tracking Viewpoint updated only with toVector inputs will be as a TV camera mounted on a fixed tripod having only azimuth and elevation pivots. A magnification of 2 will place the effective viewpoint halfway between the specified camera position and the target.
Magnification is only in effect if the standoffDistance is less than or equal to zero.
When an object tends to travel a good distance toward and away from the camera position, having a constant magnification factor can cause the object to sometimes appear too large and sometimes too small. So the standoffDistance field was created to allow tracking an object from what appears to be a fixed distance. This allows the author to fill the browser window with mostly the object regardless of how close or far it gets. Like magnification above, standoffDistance is implemented by sliding the effective viewpoint along the line of sight backward from the target by a fixed distance. When standoff distance is set to a value less than or equal to zero, the last computed value for magnification is used.