Hey, guys! First of all sorry for my bad English, I hope you can understand everything I am working on a Top-down game similar to Alundra: . The player and other instances are able to jump on other objects and platforms. Everything works with collision masks and with the function "place_meeting". I invested so much time to implement this features but it still doesn't work very well. Every instance has following variables: jump (the truth value decides whether the object jumps or not) z (the z-axis) z_ground (the height of the object under this instance) height (the height of the object) z_speed (speed for the jump) So, I have the problem that I don't know exactly how to define the depth of the objects. First I thought "depth=-y-z_ground" was a good solution but when the player is in front of stacked objects and he starts jumping this happens: https://dl.dropboxusercontent.com/s/xhb2oirccv9mvb3/Help.png?dl=0 Do you have any ideas how I can define the depth properly? Regards, Kerberos.