Well, I think we are talking about two different things here. 1/ If you want to find the coordinates of a vertex, well, they are far apart no matter what method one applies to find them. 2/ Finding a point of a trace hit I suppose will be the point interpolated inbetween vertices of the polygonized terrain if that is chosen for the trace. I have a hard time to see how a trace hit on the bounding box of the terrain would be more accurate. Maybe i misunderstand. Could you elaborate a bit ...