ProximitySensor Example

Many people have asked how to have a shape, or group of shapes, keeping its relative position to the user when the user is moving. This example shows you how to do that.

ProximitySensor nodes can be used to keep track of the users position and orientation. Two eventOuts are provided for this effect:

position_changed

orientation_changed

Therefore a ProximitySensor node generates events whenever the user changes its position or orientation. These events can then be routed to a Transform node where the shapes are placed.

The only problem with this method is that a ProximitySensor requires the definition of the size of a virtual box. If the user is outside the virtual box then the ProximitySensor will NOT generate events. To avoid this problem one can always define the size of the ProximitySensor to be larger than the world itself.

The following code should do the trick:

Example:

#VRML V2.0 utf8

Group {

}

ROUTE ps.position_changed TO tr.set_translation

ROUTE ps.orientation_changed TO tr.set_rotation

Note that the sphere which is 'locked' to the user position is inside a Transform node which contains a translation. This translation defines the relative position to the user, in this case the center of the sphere will be 5 units away from the user.

Press the button below to see the VRML. Note that there is also a box in the world. The box should remain in its position while you move, only the sphere will follow your movement.