Hello Everyone, I have an issue here, its related to math but some hints are appretiated. The player has to position 3d models on a sphere which is the globe. For example a building.. and after plotting I have to display the distance between his poltted position and the accurate position. I am getting the player chosen point by a raycast, so on mouse down the model will be plotted and I save have the hit point and the other point is defined by me. I have positioned small sphere's at the accurate position, so the position of these sphere's have to be compared to the hit point(position) to get the distance(arc distance) I think to get the arc distance I need a third point which is the center of the sphere(globe) and hence I can get the radus, since the hit point and the original position is the on surface of the globe. I really appretiate any help!