When partitioning the space with grids, there are some situations that obstacle would occupy half a cell. When using BSP, i wonder is it good to just partition the tiles that are partially occupied, and ignore the regular ones instead of partitioning right from the scene as a whole?
I do this because this way the pathfinder may generate "ugly" paths, also I am using cooperative pathfinding, if each tile varies in size, cooperative pathfinding is hard to accomplish.
Thanks
Jack

Using the 'grid' you can add that obstacle to both (or possibly upto 4) tiles that object is in,
either that or you should also check not just whats in the tile but also whats in the 8 adjacent tiles (to that tile)....