# How to detect stuffs are out of edge?

 Topics: Developer Forum, Project Management Forum, User Forum Wiki Link: [discussion:413386]
 Jundai Dec 21, 2012 at 4:00 AM I want to design something like this http://www.gamedesign.jp/flash/block/block.html when the small ball runs out of edge, game is over i don't know how to detect this   I am fresh man in game design...simple explanation pls thank you very much Genbox Coordinator Dec 21, 2012 at 4:16 AM The simplest way of doing it, is to do a simple plane check: if (ball.Y < -30) {    //Ball is below the line } else {    //Ball is above the line } The -30 (meters) determine where in the world the threshold should be on the Y-Axis. Imagine a screen with (0,0) as the center of the screen:             ----------------------------- Y= 20  |                                         | Y= 10  |                                         | Y= 0    |                                         | Y= -10 |                                         | Y= -20 |                                         |              ----------------------------- Then Y = 30 is below the screen, and you simply check if the ball has a Y coordinate below the screen. Jundai Dec 21, 2012 at 4:30 AM Thank you   Do I need to define the "Y"? Is it already defined in Farseer? Genbox Coordinator Dec 22, 2012 at 2:19 AM Y is referring to the Y component in a coordinate. I just did not want to write (x,y=20).