Hello, EDIT: The title says Perpendicular but it is parrallel. I've a problem to keep game objects parallels to other gameobjects depending the orientation on a surface. To explain you, the user touch the screen to place two points (A and B) on a horizontal surface. Once the two point A and B are placed on the surface, I place programmatically a point (C) who must stay parrallel, same distance, to the line of point A- B. I would like to achieve to get this, stay parallel in all rotation of A-B : http://zupimages.net/viewer.php?id=19/30/e5nj.png I Arrive to get it parrallel if A-B is vertical, but if A-B is diagonal and more horizontal , C come over A-B. http://zupimages.net/viewer.php?id=19/30/s4k1.png I Think it's a question of angle or distance, i'am stuck since 1 weeks, your helps will be really appreciate. Thanks you.