JWstudios, ome6a1717 is right. The case is, I have a topview game using 8 directions behavior and 2 players. I want to make sure that both of players will be on the screen. They can't pass through the screen border. I was thinking about to have a collision on the edge of the top fixed layer that would avoid the players to go out. But it would also avoid other actors, like enemies, to go into the player. Because of this I was thinking about to have a collision that would work only with a kind of object. Is there another idea about how to make it work?