Ok so I know this is probably a dumb question but I cant figure the best way to do this. Right now i basically layout this grid of tiles (Square) when I move along the tiles I can tell my exact tile location. From this I can get all the Vectors I need to define the specific tiles plane. So my first theory was since I know my positions X and Z value and I know that my tiles are all the same width and length then I only have to get my height value to determine where I should be to be ON the surface. With that in mind I did the old cross Product routine to get the Normal of the plane then I got the dot product using the normal and anypoint already on the plain. But this is where I am stuck. with this information how do I know where the point directly above me that lies ON the plane is. ? Is this a good way to do Surface collision ? I figure by knowing where the surface is below or above me is all I need for this type of detection. If someone could give me some info I would appreciate it. Or if ya have a better way of doing surface collision detection let me know. I dont really want to use a sphere type detection with the ground. Seems to be alot of fus for this type of detection.