I assume Pix wrote his editor to be able to create the graph data for the pathfinding to work on, the A* is the easy bit. My solution in Bmax took a week, 2 days to write the A* as I had no idea what it was and the rest of the time to find a way to generate data from a test level on which it could chew. My Lua A* took a day to write from scratch, with most of that time spent learning Lua, I am now still finding ways to generate the data for a level on which it can chew. This time had to be spent, as LE has no inherent pathfinding. I'd prefer to just use a library built into the engine also, but until there is a version of LE that has that functionality there is not a lot of options.