<html><head><meta http-equiv="Content-Type" content="text/html; charset=utf-8"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;" class="">Alice does not provide explicit access to the virtual world’s underlying coordinate system anywhere but in Scene Setup. That being said, by setting an object as a reference point somewhere in your scene and using the distanceTo function of an object you will be able to make sure the object stays within your predetermined boundaries (radius from threference.<div class=""><br class=""></div><div class="">I have attached a world, <i class="">ReferencePoint</i><span style="font-style: normal;" class=""> as </span>demonstration. The program uses a Disc shape as the reference point. It moves and orients the disc to the ground (0,0,0) in the underlying coordinate system, and then sets its opacity to 0.0. (I would normally set this in the Scene Setup). The alien checks its distance from the disc and reports what it has found out. Then the alien moves to the disc, then moves away from the disc until it is more than 5>0 meters away, turns around and comes back. </div><div class=""><br class=""></div><div class="">Also demonstrated in this world is the exitViewListener event (click on the initializeEvents tab) which will trigger a response whenever an object or objects exits the camera view. Of course this will not work if the object is moving away from the camera and stays within frame, but it is handy for keeping objects from moving off the left and right edges of the screen.</div><div class=""><br class=""></div><div class="">Please let us know if you have any other questions.</div><div class=""><br class=""></div><div class="">All the best,</div><div class="">Don Slater</div><div class=""><br class=""></div><div class="">Alice Project</div><div class=""><br class=""></div><div class=""></div></body></html>